Blockchain-based building information model three-dimensional trust evaluation system

Abstract

The application relates to the technical field of building information model, in particular to a three-dimension trust evaluation system for building information model based on a blockchain. An off-chain BIM data bearing module is used for storing full-amount building information model files and supporting business data, and extracting two types of basic verification data, namely model hash and metadata; a cross-system API interaction bridge module is used for connecting the BIM design software, the off-chain data bearing module and the alliance chain node; an alliance chain storage module is used for constructing a distributed trusted account book and storing lightweight core verification data; a three-dimension trust evaluation engine internally has a data integrity evaluation unit, a process compliance evaluation unit and a subject identity trust evaluation unit, and the three-dimension trust evaluation engine is used for performing quantitative trust degree calculation on a target building information model from three dimensions of a data layer, a process layer and a subject layer, and generating a comprehensive trust rating result; and an evaluation certificate generation module is used for generating a digital trust certificate by combining the comprehensive trust rating result and the evaluation basis.

Description

Technical Field

[0001] This invention relates to the field of building information modeling technology, and more specifically, to a blockchain-based three-dimensional trustworthy assessment system for building information models. Background Technology

[0002] With the advancement of digital transformation in the construction industry, BIM technology has become a core data carrier throughout the entire building lifecycle, playing a crucial role in design, construction, and operation and maintenance. However, there are significant shortcomings in ensuring the reliability of current BIM models: First, the trust assessment has a single dimension. Existing solutions mostly rely on simple hash storage to verify data integrity, which does not cover core dimensions such as compliance of business processes and credibility of participating entities. This makes it impossible to systematically guarantee the overall credibility of the BIM model and meet the legal acceptance requirements for project delivery. Secondly, it is difficult to balance on-chain storage efficiency and trustworthiness. If all BIM data is put on the chain, the storage cost is high and the operating efficiency is low, which cannot meet the high-frequency iteration needs of large-scale models. If only a small amount of data is stored, there is a lack of complete evaluation basis, which cannot support refined trust assessment. Third, there is a lack of dynamic trust throughout the entire lifecycle. Existing solutions mostly provide one-time evidence storage for static design models, without considering the dynamic correction of models brought about by human-machine collaborative construction during the construction phase. This makes it impossible to achieve dynamic trust iteration from virtual design to physical construction, and it is difficult to support the credibility guarantee of digital twin models. Fourth, cross-disciplinary data exchange relies on centralized platforms, and model transmission needs to be relayed through third-party platforms, which poses both the risk of data leakage and the single point of trust dependence, making it impossible to achieve end-to-end trusted data exchange.

[0003] Therefore, there is an urgent need in this field to develop a systematic BIM credibility assessment system that takes into account multi-dimensional assessment, efficient storage, dynamic updates throughout the entire lifecycle, and end-to-end credible exchange, so as to meet the credible data needs of the construction industry's digital transformation. Summary of the Invention

[0004] In view of this, the present invention provides a three-dimensional trust assessment system for building information models based on blockchain, aiming to solve the technical problems of existing BIM trust assessments which have only one dimension and cannot systematically cover the trustworthiness of data, processes, and subjects; the difficulty in balancing blockchain storage costs and assessment completeness, resulting in low efficiency in uploading large volumes of BIM data to the blockchain; the lack of a dynamic trust assessment mechanism during the construction phase, which cannot support the trustworthiness of digital twins throughout their entire lifecycle; and the reliance on centralized relays for cross-professional model exchanges, leading to insufficient end-to-end trustworthiness.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A blockchain-based three-dimensional trust assessment system for building information models includes: an off-chain BIM data carrying module, a cross-system API interaction bridge module, a consortium blockchain notarization module, a three-dimensional trust assessment engine, and an assessment certificate generation module. The off-chain BIM data carrier module is used to store the full amount of building information model files and supporting business data, and extract two types of basic verification data: model hash and metadata. The cross-system API interaction bridge module is used to connect BIM design software, off-chain data carrier module and consortium chain node to realize automatic data extraction, verification triggering, evidence storage on the chain and evaluation result feedback. The consortium blockchain evidence storage module is used to build a distributed trusted ledger, storing five types of lightweight core verification data: hash value, metadata, transaction records, smart contract code, and permission and identity information, providing tamper-proof underlying data support for trust assessment. The three-dimensional trust assessment engine has built-in data integrity assessment unit, process compliance assessment unit, and subject identity credibility assessment unit. It performs quantitative trust calculation on the target building information model from three dimensions: data layer, process layer, and subject layer, respectively, and generates a comprehensive trust rating result. The assessment certificate generation module is used to generate digital trust certificates by combining the comprehensive trust rating results with the assessment basis, synchronously upload them to the blockchain for storage, and output them to the business terminal.

[0006] Furthermore, the data integrity assessment unit adopts a three-level hash anchoring mechanism for integrity verification. The three-level hash includes global file hash, key component-level feature hash, and version incremental hash. During the assessment, the three-level hash value of the off-chain model to be verified is compared one by one with the hash value of the corresponding version in the consortium blockchain notarization module, and the data integrity trust score is calculated based on the hash matching degree.

[0007] Furthermore, the process compliance assessment unit sets up a two-stage verification rule: in the design stage, the model's standard compliance is verified by automatically verifying the modeling depth, attribute completeness, and professional collaboration rules against BIM delivery standards and drafting specifications; in the completion stage, the compliance of the entire process is verified by traversing on-chain transaction records to verify the process completeness of design approval, change orders, and acceptance of sub-items, and the process compliance trust score is calculated based on the proportion of compliant items.

[0008] Furthermore, the subject identity trust assessment unit implements identity verification based on a dual-trust root architecture, wherein the dual trust roots include a root identity certificate issued by an industry-authoritative CA and an on-chain distributed digital identity (DID). During the assessment, the validity of the certificate signature of the operating subject, the consistency of the on-chain DID anchoring, and the matching degree of the operating permissions are verified, and the subject identity trust score is calculated based on the verification results.

[0009] Furthermore, the consortium blockchain evidence storage module implements a hot-cold tiered storage mechanism for five types of lightweight core verification data: the current effective version hash, active business metadata, recent transaction records, running smart contract code, and valid permission and identity information are stored as hot data in the on-chain state database; historical version hashes, archived metadata, overdue transaction records, deactivated contract code, and expired identity and permissions are packaged as cold data and archived to off-chain distributed storage, with only the cold data archive hash index remaining on the chain, and the integrity of the archived data can be verified through the index hash.

[0010] Furthermore, the cross-system API interaction bridge module includes an upload and evidence storage subframe and a distribution and verification subframe. The upload and evidence storage subframe is embedded in the BIM design end and automatically triggers pre-compliance verification before the model is uploaded to the blockchain. After the verification is passed, metadata extraction, hash calculation and evidence storage on the blockchain are completed. The distribution and verification subframe provides a standardized query interface to the receiving end, supporting the model recipient to call the trust assessment capability. The model file itself does not go through the API platform.

[0011] Furthermore, it also includes an end-to-end trusted transmission verification module to support direct point-to-point transmission of models. The end-to-end trusted transmission verification module constructs a five-level mapping link: BIM physical file, three-level hash fingerprint, version authentication certificate, on-chain evidence storage record, and root identity certificate. The receiver performs three-level verification through local verification of certificate signature, on-chain comparison of certificate hash, and local calculation of file hash, thereby completing the verification of model integrity and legality without a centralized relay.

[0012] Furthermore, the system also includes a human-machine collaborative construction dynamic evaluation module for dynamic trust updates of the model during the construction phase. The dynamic evaluation module collects actual measurement data from on-site construction robots, 3D scanning equipment, and IoT sensors. After hashing the data and storing it on the blockchain, it compares the design model to calculate construction deviations and automatically updates the model's trust rating based on the compliance of the deviations and the correction approval records, thereby realizing dynamic trust iteration from virtual design to physical construction.

[0013] Furthermore, the human-machine collaborative construction dynamic evaluation module adopts a four-level phased incremental evaluation mechanism, namely component level, sub-item project level, sub-section project level, and unit project level. Each completion of a construction node triggers an incremental trust evaluation, recalculating the trust score only for the changed parts, and aggregating them level by level to form a comprehensive trust rating for the entire model.

[0014] Furthermore, the digital trust certificate generated by the evaluation certificate generation module includes a unique model identifier, a comprehensive trust rating, three-dimensional sub-item scores, evaluation basis hash, and evaluation time. After being digitally signed by the evaluation subject, the certificate is permanently stored on the blockchain and serves as a trustworthy basis for BIM model delivery, as-built digital twin certification, cross-professional data exchange, and data acceptance during the operation and maintenance phases.

[0015] Compared to existing technologies, this invention breaks through the limitations of existing single hash-based evidence storage. It quantifies and rates BIM models from three levels: data integrity, process compliance, and subject identity credibility, comprehensively covering the credibility requirements in engineering scenarios and providing a systematic basis for model delivery and acceptance. For human-machine collaborative construction scenarios, it combines on-site measurement data to achieve phased incremental updates of model trust, establishing a credible link from virtual design to physical construction and providing continuous credible support for digital twin models. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the overall architecture of a system according to the present invention. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] This embodiment provides a blockchain-based three-dimensional trustworthy assessment system for Building Information Modeling (BIM), applied to the full lifecycle trustworthy management of BIM in a commercial complex project. The overall system architecture is as follows: Figure 1 As shown, it includes an off-chain BIM data carrier module, a cross-system API interaction bridge module, a consortium blockchain evidence storage module, a three-dimensional trust assessment engine, an assessment credential generation module, an end-to-end trusted transmission verification module, and a human-machine collaborative construction dynamic assessment module.

[0020] In this embodiment, the underlying consortium blockchain adopts an independently controllable consortium blockchain platform that supports national cryptographic algorithms (such as ChainMaker 2.3 or FISCO BCOS 3.0). A total of 7 consensus nodes are deployed, one each held by the construction unit, architectural design unit, structural design unit, construction drawing review agency, engineering supervision unit, general contracting unit, and housing and construction industry regulatory department. The improved credit PBFT consensus algorithm is adopted, with a single-chain transaction throughput of ≥5000TPS and a transaction confirmation latency of ≤500ms. Synchronization nodes are connected on demand, including electromechanical subcontractors, decoration subcontractors, operation and maintenance units, etc., which only synchronize ledger data and do not participate in consensus.

[0021] The off-chain BIM data carrier module deploys a distributed object storage cluster (using a MinIO distributed architecture with 3 redundant backup nodes) and IPFS content addressing nodes to store the full amount of BIM source files, specification libraries, and business data; the cross-system API interaction bridge module is deployed using a Spring Cloud microservice architecture, providing standardized RESTful interfaces, and the entire link uses the national cryptographic standard SM4 for encrypted transmission.

[0022] The BIM-side adapter plugin supports mainstream BIM software such as Autodesk Revit 2020-2024, Bentley MicroStationCONNECT, and Tekla Structures 2022. It achieves embedded integration through the software's native secondary development interface, allowing designers to complete evidence storage, verification, and evaluation operations without leaving the design environment.

[0023] The off-chain BIM data carrier module stores BIM files in a three-level directory structure of unique project ID, professional category, and version number. It supports storage of multiple file formats such as RVT, IFC, DWG, and PDF. Each version corresponds to an independent file directory and is accompanied by a metadata description file.

[0024] The module incorporates an IFC parsing engine (developed based on xBIM Toolkit) and a national cryptographic hash calculation unit, performing three types of hash calculations: Global file hash: Read the complete binary file stream of the BIM model, perform full calculation using the national cryptographic SM3 hash algorithm, and output a fixed-length digest of 256 bits as the digital fingerprint of the model as a whole; any byte modification in the same file will cause an irreversible change in the global hash.

[0025] Key component-level feature hashing: The IFC parsing engine extracts the attribute set of important objects such as core load-bearing components, key electromechanical pipelines, and prefabricated components in the model, including five core fields: component globally unique identifier (GUID), geometric contour parameters, material number, specification model, and design parameters. The field values ​​of a single component are concatenated into a feature string in a fixed order, and SM3 hashes are calculated one by one to form a component hash list. In this embodiment, feature hashing is only calculated for key components that account for 10%-20% of the total number of components. Non-core components are not included in the on-chain scope to ensure lightweight design.

[0026] Version Incremental Hash: The IFC differential comparison algorithm is used to compare the models of two adjacent versions at the component level and filter out the set of changed components that have been added, modified, or deleted. The SM3 hash is calculated only on the feature set of the changed components to generate the incremental hash digest of the current version. There is no need to recalculate the entire file, which is suitable for high-frequency iteration scenarios.

[0027] The metadata extraction unit is based on the IFC standard and the "Classification and Coding Standard for Building Information Modeling". It extracts 12 mandatory governance fields: unique model ID, version number, professional type, file format, creation timestamp, project ID, responsible person DID, design, review and approval status, approval node identifier, delivery stage code, change number, and associated certificate ID. The compressed metadata of a single version is ≤800 bytes and does not contain any geometric parameters or business-sensitive data.

[0028] The cross-system API interaction bridge module is divided into an upload and evidence storage subframework and a distribution and verification subframework. Both types of subframeworks provide services to the outside world in a unified manner through the API gateway. Interface requests must carry an authentication token with an on-chain identity signature. Requests without a legitimate identity are directly intercepted.

[0029] The upload and evidence storage subframework is deployed as an embedded plugin in the BIM design terminal. Its core interface is ` / api / model / deposit`, and request parameters include: model file path, project ID, version number, and operator identification credentials. The internal execution flow of the interface is as follows: it calls the off-chain data carrier module to complete file storage; it triggers metadata extraction and three-level hash calculation; it calls the pre-design compliance verification engine; after successful verification, it encapsulates five types of verification data into a blockchain transaction and submits it to the consortium blockchain via the node SDK; it receives the on-chain transaction receipt and returns the evidence storage success status and transaction hash to the design terminal.

[0030] In this embodiment, designers can trigger the entire process by clicking the "Save and Record" button in the BIM software. If the verification fails, the plugin interface accurately marks the location of non-compliant components and the basis for rectification, without the need to switch systems.

[0031] Distribution Verification Sub-Framework: Deployed by model recipients and business systems, its core interfaces include / api / verify / hash (hash verification interface), / api / verify / certificate (certificate verification interface), and / api / assess / query (trust rating query interface). All interfaces only return verification results, rating information, and credential hashes, not the original model data, ensuring data security. The model files themselves are transmitted via peer-to-peer channels, without passing through the API gateway.

[0032] The distributed ledger of the consortium blockchain's evidence storage module stores only five types of lightweight core verification data, all of which are stored on-chain in the form of contract structures: Hash value structure: contains global file hash, component hash array, incremental hash, hash algorithm identifier, calculation timestamp, and the total length of a single data entry is ≤1KB.

[0033] Metadata structure: contains 12 mandatory governance fields, uses RLP encoding for compressed storage, and each data entry is ≤800 bytes.

[0034] Transaction record structure: includes transaction ID, operation subject DID, operation type enumeration (proof / modification / approval / authentication / permission change), operation timestamp, associated version hash, and operation remarks hash. Each record is ≤256 bytes. All operation records are linked together in chronological order to form a complete audit chain.

[0035] Smart Contract Code: A modular contract architecture is adopted, deploying four core smart contracts: the Identity Management Contract, responsible for DID registration, identity certificate anchoring, and state updates; the Evidence Storage Contract, responsible for on-chain storage and retrieval of hashes, metadata, and transaction records; the Evaluation Contract, with built-in three-dimensional evaluation rules and scoring logic, automatically executes trust rating calculations; and the Permission Contract, responsible for role permission matrix management and operation permission verification. Among these, the Identity Management Contract and Evidence Storage Contract are globally universal contracts, with only one set deployed across the entire platform; the Evaluation Contract and Permission Contract are deployed as lightweight configuration instances at the project level, storing only project-specific parameters, while reusing the global contract for general logic, minimizing on-chain code redundancy.

[0036] Permissions and Identity Structure: Includes subject DID, root certificate public key hash, role identifier, project permission list, and authorization validity period. Single subject data ≤ 512 bytes.

[0037] This module has a built-in hot / cold tier management contract that automatically executes data flow: Hot data retention rules: The hash and metadata of the current effective version are permanently retained on the blockchain; the transaction records of projects under construction for the past 6 months are retained on the blockchain; the permission configuration and contract code of running projects are retained on the blockchain; and the final authentication hash of completed projects is permanently retained on the blockchain.

[0038] Cold data archiving rules: On the 1st of each month, an archiving task is automatically triggered, which packages historical version hashes that have exceeded the retention period, expired transaction records, invalid permission data, and deactivated contract code into archive data packages by project dimension. After calculating the global archive hash, the archive hash, data range, storage address, and archive time are written to the chain as indexes. The original cold data on the chain is synchronously cleaned up to release on-chain storage space.

[0039] The three-dimensional trust assessment engine is achieved through the collaboration of smart contracts and off-chain edge computing. The rules and logic are stored on the chain and cannot be tampered with. The computationally intensive model parsing work is performed on off-chain edge nodes, and only the calculation results are uploaded to the chain, balancing trustworthiness and execution efficiency.

[0040] During the data integrity assessment, the unit obtains the on-chain standard hash set and compares it one by one with the calculated hash of the model to be verified, and automatically calculates the integrity score.

[0041] The scoring formula is as follows: , in, =0.6 is the global hash weight. This represents the global hash matching rate (1 for a match, 0 for a non-match). =0.3 is the component hash weight. The critical component hash matching rate (number of matching components / total number of critical components). =0.1 is the incremental hash weight. This represents the incremental hash match rate.

[0042] The process compliance assessment unit is used to set up a two-stage verification rule base: Design phase standard compliance verification: a total of 18 verification points, covering 5 major categories including modeling depth requirements, component naming specifications, attribute information integrity, professional collaboration collision rules, and drawing standard matching degree. A rule base is constructed by comparing with the "Building Information Modeling Design Delivery Standard" GB / T 51301 and the "Building Engineering Design Information Modeling Drawing Standard" JGJ / T 448. Compliance verification of the completion phase process: There are 12 verification points in total, covering 6 major categories, including design approval records, design review process, design change visa, acceptance of concealed works, acceptance of sub-items and components, and integrity of multi-party signatures and approvals. A rule base is constructed in accordance with the "Construction Electronic Documents and Electronic Archives Management Standard" CJJ / T 117.

[0043] The scoring formula is as follows: , in For the number of compliant items, This represents the total number of verification items. For stage weights; design stage =1, with a standard compliance weight of 0.4 and a process compliance weight of 0.6 for the completion stage.

[0044] The entity identity trust assessment unit performs a three-step verification method: 1. Certificate Validity Verification: Verify whether the digital signature of the root identity certificate was issued by an industry-authoritative CA, whether the certificate is valid, and whether it is on the revocation list; 2. On-chain anchoring verification: Verify whether the binding relationship between the certificate public key hash and the on-chain DID account is consistent, and whether the certificate status is valid; 3. Permission matching verification: Verify whether the role permissions of the operating subject cover the current operation and whether it is within the authorization validity period.

[0045] Scoring rules: A perfect score of 100 points is awarded for passing all three steps; 40 points are deducted for an expired certificate, 60 points are deducted for not being anchored on the blockchain, and 30 points are deducted for insufficient permissions; 0 points are awarded for cases of forged certificates or impersonation, and the person is deemed untrustworthy.

[0046] The formula for calculating the overall trust rating is: , in The rating is based on the credibility of the subject's identity. The rating criteria are as follows: a total score of ≥90 points is [credible], a total score of 70 points ≤ total score <90 points is [basically credible], and a total score <70 points is [unreliable].

[0047] The end-to-end trusted transmission verification module is based on the X.509 v3 digital certificate standard and extends to build a three-level certificate system. It supports the national cryptographic SM2 signature algorithm and realizes point-to-point trusted transmission without a centralized relay.

[0048] Specific implementation of Level 3 certificate: Root identity certificate: issued by a third-party electronic authentication service agency recognized in the housing and construction sector, containing the enterprise's unified social credit code, individual professional qualification registration number, public key, validity period, and issuing agency signature, and bound one-to-one with the on-chain DID; the certificate body is stored on local hardware encryption medium (UKey / encryption machine), and the public key hash is stored on the chain for evidence.

[0049] Model version authentication certificate: issued by the model publisher using the root identity certificate private key, and each version model corresponds to a unique certificate; the certificate extended fields include: project ID, model ID, version number, global file hash, key component hash list, compliance verification result hash, and publisher signature.

[0050] Session transmission credentials: Temporarily generated before each transmission, containing the receiver's DID, transmission version ID, timestamp, random number, and sender's signature. Valid for 15 minutes and automatically expires upon completion of transmission.

[0051] Five-level mapping verification logic: Physical file to hash mapping: Changes in file content inevitably lead to changes in hash value, which is a strong cryptographic binding; Hash-to-Version Certificate Mapping: The hash field is included in the certificate signature scope; a change in the hash invalidates the certificate signature. Version certificate to on-chain evidence mapping: Certificate hash is stored on the chain, and certificate tampering can be identified by comparing on-chain hashes; On-chain evidence storage to root identity mapping: The issuer's DID is bound on-chain to the root certificate's public key hash, making the identity unforgeable; Root identity to compliance qualification mapping: Root certificates are issued by authoritative CAs, and the identity has legal validity.

[0052] The human-machine collaborative construction dynamic evaluation module connects to multi-source acquisition equipment at the construction site to achieve dynamic incremental updates of model trust during the construction process.

[0053] The data acquisition layer interfaces with three types of devices: Geometric acquisition equipment: 3D laser scanner, total station, construction robot positioning system, to acquire the actual spatial coordinates and geometric dimensions of components; IoT sensing devices: RFID tags, temperature and humidity sensors, stress sensors, to collect component identification information and material performance parameters; Business system data: Acceptance records, change orders, and rectification instructions from the construction management system.

[0054] All collected data is preprocessed by the edge gateway (denoising, coordinate alignment, and format standardization), and a data snapshot is generated and an SM3 hash is calculated. The data is first stored on the blockchain for evidence and then used for model correction to ensure the trustworthiness of the data source.

[0055] Deviation grading correction rules: Class 1 deviation (≤ permissible value in the specification): such as precast component size deviation ≤ 5mm, installation positioning deviation ≤ 10mm, the system will automatically trigger model parameter correction, update the corresponding component hash and metadata, and adjust the trust rating synchronously. Type 2 deviation (permissible value in the specification to twice the permissible value): The system will issue an automatic warning, submit it to the supervising engineer for review, and after the review is approved and the engineer signs to confirm, the model will be corrected and the review record will be stored on the blockchain for evidence. Type 3 deviations (>2 times the allowable value): trigger the design change process. The design unit must issue a formal change document and the construction unit must sign and approve it before the model correction can be implemented. The change document hash and the approval record are synchronously uploaded to the blockchain.

[0056] Phased incremental evaluation mechanism: It is progressively divided into four levels: component level, sub-item level, sub-section level, and unit level. After each level is completed, only the trust score of the changed components within the scope of that level is recalculated, and the overall rating is updated by aggregating upwards. There is no need to re-evaluate the entire model, which greatly improves the efficiency of dynamic evaluation.

[0057] Example 1: BIM Model Preservation and Three-Dimensional Trust Assessment in the Design Phase This example applies to the delivery of architectural design models for a commercial complex project. The complete process is as follows: 1. Designers complete the V1.0 architectural model drawing in Revit software, click the [Save and Record] button in the plugin bar, and trigger the on-chain application; 2. The uploaded evidence storage subframe automatically calls the IFC parsing engine to extract 12 metadata fields and calculate the global file hash and the feature hashes of 236 core components; 3. The design phase compliance verification engine was invoked to automatically review against 18 standard verification points, and two missing component attributes were detected. The locations were marked on the plugin interface and rectification was prompted. After the designer completed the rectification, the design was resubmitted. 4. Once all compliance checks are passed, the system generates a notarized transaction, including hash, metadata, operation records, and permission verification information, which is then submitted to the consortium blockchain through the design unit node. 5. The consortium blockchain consensus nodes complete transaction verification and consensus, write five types of data into the distributed ledger, and return a transaction success receipt and block height; 6. The three-dimensional trust assessment engine automatically triggers the assessment: data integrity score 100 points, process compliance score 100 points, subject identity trust score 100 points, overall score 100 points, and the rating is [Trustworthy]; 7. The evaluation certificate generation module generates a digital trusted certificate, which includes model identifier, version number, sub-item score, comprehensive rating, evaluation basis hash, and evaluation time. After being digitally signed by the design unit, the certificate hash is stored on the blockchain. 8. Design a terminal to receive successful evidence storage receipts and trusted credentials, and complete the trusted evidence storage and evaluation of the design model.

[0058] Example 2: Dynamic Trust Assessment for Precast Component Installation During Construction This embodiment applies to the installation of precast columns during the main structure phase of a project. The complete process is as follows: 1. After the prefabricated components are processed in the factory, the actual dimensions of the components are obtained through 3D scanning, the processing deviation is calculated to be 3mm (belonging to Class 1 deviation), and the measured data is hashed and stored on the blockchain for evidence. 2. The system automatically triggers component-level model correction, updates the geometric parameters of the precast columns, generates the current incremental hash, and corrects the data based on the hash of the associated measured data; 3. The component-level evaluation unit recalculates the trust score of the component, the overall rating remains [trustworthy], and the component-level authentication certificate is simultaneously uploaded to the blockchain; 4. After the precast column is hoisted on site, the robot positioning system collects the installation coordinates. The actual measured positioning deviation is 8mm (belonging to Class 1 deviation). The installation data is hashed and stored on the blockchain for evidence. 5. The system automatically corrects the spatial position parameters of the components in the model and updates the incremental hash; the sub-project evaluation unit aggregates the evaluation results of the 12 precast columns in this batch and generates the sub-project trust rating. 6. After the main structure is capped, the system aggregates the evaluation data of all components and sub-items, combines the hidden works acceptance records and sub-item acceptance records, performs dynamic evaluation at the sub-project level, generates a digital twin trust rating for the main structure sub-project, and uploads the rating results and acceptance certificates to the blockchain simultaneously.

[0059] Example 3: End-to-End Trusted Authentication of Digital Twin Models in the Completion Phase This embodiment is applied to the final certification of digital twin models during the project completion and acceptance phase. The complete process is as follows: 1. The general contractor submits the as-built BIM model and full-cycle acceptance data, triggering the application for completion certification; 2. The system traverses the entire lifecycle of on-chain transaction records, performs full-process compliance verification, checks 12 completion process verification points, and confirms that all design changes, acceptance records, and approval procedures are complete and traceable; 3. The data integrity assessment unit verifies the consistency between the global hash of the as-built model and the incremental hash chain throughout the entire lifecycle, confirming that the model data is continuous, complete, and has not been tampered with; 4. The entity identity assessment unit verifies the identity validity and operational authority compliance of all participants; 5. The three-dimensional evaluation engine calculates the final score as follows: Data integrity 98 points, process compliance 95 points, entity identity trustworthiness 100 points, overall score 97.25 points, rating as [Trustworthy]; 6. The five parties involved in construction, design, review, supervision, and construction confirm the authentication results and reach a consensus through on-chain multi-signature functionality; 7. Generate a digital twin certificate of completion and a trusted authentication certificate. The certificate hash is permanently stored on the blockchain as a legally credible basis for the completion and delivery of the project. 8. All data of the completed model is transferred to the cold archiving process, and only the final authentication hash and metadata index are retained as hot data. All historical data is packaged and archived to off-chain storage to ensure long-term reliability while reducing storage costs.

[0060] The implementation methods for cold data retrieval and exception handling are as follows: 1. Cold data retrieval process When you need to retrieve historical archived data, perform the following steps: The applicant submits a retrieval request and identity credentials. After the system verifies the permissions, it retrieves the corresponding archive index information from the blockchain. Based on the storage address in the index, it retrieves the archive data package from off-chain cold storage. The system calculates the global hash of the data package locally and compares it with the archive hash on the blockchain to verify the data integrity and originality. If the hash comparison is successful, the archive data is parsed, and the retrieval record is synchronously uploaded to the blockchain for record-keeping. If the comparison fails, the retrieval is blocked and a data anomaly alarm is triggered.

[0061] 2. Handling Abnormal Scenarios Hash verification fails: The system automatically blocks the use of the model, records the abnormal details, triggers a tampering alarm, notifies the project administrator and the monitoring node, and permanently records the abnormality on the blockchain. Certificate expired / revoked: The system automatically blocks the operation application of the corresponding subject, prompts for certificate renewal, and marks the previously issued historical certificates as invalid, requiring re-authentication; Insufficient permissions: The system rejects the corresponding operation request, records the unauthorized attempts, and triggers temporary account freezing after 3 consecutive unauthorized attempts.

[0062] Compared with the prior art, the present invention has the following beneficial effects: Breaking through the limitations of existing single hash-based evidence storage, this paper quantifies and rates BIM models from three aspects: data integrity, process compliance, and subject identity credibility. This comprehensively covers the credibility requirements in engineering scenarios and provides a systematic basis for model delivery and acceptance.

[0063] Highly efficient and lightweight evidence storage architecture: It adopts a five-category on-chain data storage and cold and hot layered storage mechanism. While ensuring the completeness of the evaluation basis, it compresses the amount of on-chain data to one millionth of the original model. This not only solves the problems of high cost and low efficiency of full on-chain storage, but also avoids evaluation distortion caused by insufficient data.

[0064] For human-machine collaborative construction scenarios, the model trust is updated in stages by combining on-site measurement data, thus establishing a trustworthy link from virtual design to physical construction and providing continuous trustworthy support for digital twin models.

[0065] By using a five-level mapping link and a three-level verification mechanism, the integrity and legality verification of the model under point-to-point direct transmission is realized, eliminating the single-point trust dependence and data leakage risk of centralized platforms, and improving the efficiency of cross-professional collaboration.

[0066] The architecture conforms to the construction industry's BIM standards and electronic document management specifications, is compatible with mainstream BIM software and blockchain platforms, and the credible credentials it issues can support the legal acceptance requirements of project archives.

[0067] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0068] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A three-dimensional trustworthy assessment system for building information models based on blockchain, characterized in that, include: The module includes an off-chain BIM data carrier module, a cross-system API interaction bridge module, a consortium blockchain notarization module, a three-dimensional trust assessment engine, and an assessment certificate generation module. The off-chain BIM data carrier module is used to store the full amount of building information model files and supporting business data, and extract two types of basic verification data: model hash and metadata. The cross-system API interaction bridge module is used to connect BIM design software, off-chain data carrier module and consortium chain node to realize automatic data extraction, verification triggering, evidence storage on the chain and evaluation result feedback. The consortium blockchain evidence storage module is used to build a distributed trusted ledger, storing five types of lightweight core verification data: hash value, metadata, transaction records, smart contract code, and permission and identity information, providing tamper-proof underlying data support for trust assessment. The three-dimensional trust assessment engine has built-in data integrity assessment unit, process compliance assessment unit, and subject identity credibility assessment unit. It performs quantitative trust calculation on the target building information model from three dimensions: data layer, process layer, and subject layer, respectively, and generates a comprehensive trust rating result. The assessment certificate generation module is used to generate digital trust certificates by combining the comprehensive trust rating results with the assessment basis, synchronously upload them to the blockchain for storage, and output them to the business terminal.

2. The three-dimensional trustworthy assessment system for building information model based on blockchain according to claim 1, characterized in that, The data integrity assessment unit uses a three-level hash anchoring mechanism for integrity verification. The three-level hash includes global file hash, key component-level feature hash, and version incremental hash. During the assessment, the three-level hash value of the off-chain model to be verified is compared one by one with the hash value of the corresponding version in the consortium blockchain notarization module, and the data integrity trust score is calculated based on the hash matching degree.

3. The three-dimensional trustworthy assessment system for building information model based on blockchain according to claim 1, characterized in that, The process compliance assessment unit is set up with two-stage verification rules: the design stage verifies the standard compliance of the model, and automatically verifies the modeling depth, attribute completeness and professional collaboration rules by comparing with BIM delivery standards and drafting specifications; During the completion phase, the entire process is verified for compliance. The on-chain transaction records are traversed to verify the completeness of the process, including design approval, change orders, and acceptance of individual components. The process compliance trust score is calculated based on the proportion of compliant items.

4. The three-dimensional trustworthy assessment system for building information model based on blockchain according to claim 1, characterized in that, The subject identity trust assessment unit implements identity verification based on a dual-trust root architecture. The dual trust roots include a root identity certificate issued by an industry-authoritative CA and an on-chain distributed digital identity (DID). During the assessment, the validity of the certificate signature of the operating subject, the consistency of the on-chain DID anchoring, and the matching degree of the operating permissions are verified, and the subject identity trust score is calculated based on the verification results.

5. The three-dimensional trustworthy assessment system for building information model based on blockchain according to claim 1, characterized in that, The consortium blockchain's evidence storage module implements a hot-cold tiered storage mechanism for five types of lightweight core verification data: the current effective version hash, active business metadata, recent transaction records, running smart contract code, and valid permission and identity information are stored as hot data in the on-chain state database; historical version hashes, archived metadata, overdue transaction records, deactivated contract code, and expired identity and permissions are packaged as cold data and archived to off-chain distributed storage, with only the cold data archive hash index remaining on the chain, and the integrity of the archived data can be verified through the index hash.

6. The three-dimensional trustworthy assessment system for building information model based on blockchain according to claim 1, characterized in that, The cross-system API interaction bridge module includes an upload and evidence storage subframe and a distribution and verification subframe. The upload and evidence storage subframe is embedded in the BIM design end and automatically triggers pre-compliance verification before the model is uploaded to the blockchain. After the verification is passed, metadata extraction, hash calculation and evidence storage on the blockchain are completed. The distribution verification subframework provides a standardized query interface to the receiving end, supporting the model recipient to call the trust assessment capability, and the model file itself does not go through the API platform.

7. A three-dimensional trustworthy assessment system for building information models based on blockchain according to claim 1, characterized in that, It also includes an end-to-end trusted transmission verification module to support direct point-to-point transmission of models. The end-to-end trusted transmission verification module constructs a five-level mapping link: BIM physical file, three-level hash fingerprint, version authentication certificate, on-chain evidence storage record, and root identity certificate. The receiver performs three-level verification through local verification of certificate signature, on-chain comparison of certificate hash, and local calculation of file hash, thereby completing the verification of model integrity and legality without a centralized relay.

8. A three-dimensional trustworthy assessment system for building information models based on blockchain according to claim 1, characterized in that, The system also includes a human-machine collaborative construction dynamic evaluation module for dynamic trust updates of the model during the construction phase. The dynamic evaluation module collects actual measurement data from on-site construction robots, 3D scanning equipment, and IoT sensors. After hashing and storing the data on the blockchain, it compares the design model to calculate construction deviations and automatically updates the model's trust rating based on the compliance of the deviations and the correction approval records, thus realizing dynamic trust iteration from virtual design to physical construction.

9. A three-dimensional trustworthy assessment system for building information models based on blockchain according to claim 1, characterized in that, The human-machine collaborative construction dynamic evaluation module adopts a four-level phased incremental evaluation mechanism, namely component level, sub-item project level, sub-section project level, and unit project level. Each completion of a construction node triggers an incremental trust evaluation, recalculating the trust score only for the changed parts, and aggregating them level by level to form a comprehensive trust rating for the entire model.

10. A three-dimensional trustworthy assessment system for building information models based on blockchain according to claim 1, characterized in that, The digital trusted certificate generated by the evaluation certificate generation module includes a unique model identifier, a comprehensive trust rating, three-dimensional sub-item scores, evaluation basis hash, and evaluation time. After being digitally signed by the evaluation subject, the certificate is permanently stored on the blockchain and serves as a trusted basis for BIM model delivery, as-built digital twin certification, cross-professional data exchange, and data acceptance during the operation and maintenance phase.

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