BIM modeling method and system of building model

Abstract

The invention relates to the technical field of data processing, in particular to a BIM modeling method and system for a building model.The method comprises the steps that all models in a BIM construction simulation animation are obtained, and an observation lens exists in the BIM construction simulation animation; obtaining an evaluation result of the importance degree of the model by analyzing the distance between the observation lens and the model and the observation area of the model in combination with the volume, the vertex number and the deformation state of the model; according to the contact area between the adjacent models of each model in the BIM construction simulation animation, the importance degree of the model at each moment is corrected, and the optimal LOD hierarchy is given to each model at each moment. According to the method, the importance degree of the model at each moment in the BIM construction simulation animation and the supporting degree between the models are analyzed, and the optimal LOD hierarchy is given to the model, so that the smoothness of the BIM construction simulation animation is improved while the quality of the BIM construction simulation animation is not lost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data processing, in particular to a BIM modeling method and system for a building model. BACKGROUND

[0002] BIM modeling is a method of visualizing a building model by integrating three-dimensional model, construction progress, resources, technical points and other information. BIM model plays an important role in improving the design efficiency of the building model and optimizing the construction process by modeling the building structure, construction progress and other life cycle information.

[0003] When simulating construction by using a BIM model, all models involved in the BIM construction simulation animation need to be rendered. However, when rendering the models, LOD levels need to be assigned to the models for rendering. The traditional static LOD level rendering method mainly relies on pre-defined geometric simplification levels to balance performance and accuracy, which leads to the fact that the model only focuses on its own information and ignores its dynamic performance in the observation lens, resulting in insufficient accuracy of collision detection and construction scheme verification. The dynamic adaptation capability to real-time view requirements or key areas is lacking, and the models in the BIM construction simulation animation cannot be well rendered. SUMMARY

[0004] The present application provides a BIM modeling method and system for a building model to solve the existing problem that the traditional static LOD level rendering method cannot well render the models in the BIM construction simulation animation.

[0005] The BIM modeling method and system for a building model provided by the present application adopt the following technical solutions:

[0006] In a first aspect, an embodiment of the present application provides a BIM modeling method for a building model, which comprises the following steps:

[0007] All models in a BIM construction simulation animation are obtained, and the observation area of the models observed by an observation lens and the distance between the observation lens and the models at each time are obtained. There is one observation lens in the BIM construction simulation animation;

[0008] The basic importance of the models at each time is obtained according to the observation area of the models, the distance between the observation lens and the models, the volume of the models and the number of vertices of the models. The deformation period importance of the models at each time in the deformation period is obtained according to the difference between the volume change degree of the models and the observation area change degree of the models in the deformation period, combined with the basic importance, and the evaluation result of the importance of the models at each time is determined;

[0009] The downstream model association network of each model is obtained from the adjacent models of each model in the BIM construction simulation animation; the support degree of each model to the models in the downstream model association network is determined based on the contact area between the models in the downstream model association network of each model; the evaluation results of the importance of the model at each time step are corrected based on the support degree, and the corrected importance degree of each model at each time step is determined.

[0010] Based on the importance of each model's correction at each time step, the initial LOD level and the optimal LOD level for each model at each time step are determined.

[0011] Preferably, the specific method for obtaining the basic importance of the model at each time step includes:

[0012] The sum of the observed area of ​​the model at each time step and the preset hyperparameters is used as the denominator to calculate the ratio of the model volume to the denominator.

[0013] The product of the ratio and the distance between the observation lens and the model at each time step is negatively mapped using an exponential function. The normalized result of the negative mapping and the product of the number of model vertices is used as the basic importance of the model at each time step.

[0014] Preferably, the specific method for obtaining the importance of the model at each moment in the deformation time period and determining the evaluation result of the importance of the model at each moment includes:

[0015] The time period during which the model undergoes deformation is recorded as the deformation time period of the model;

[0016] The difference between the volume of the model at each time step during the deformation period and the volume at the previous time step is used as the numerator;

[0017] The difference between the observed area of ​​the model in the observation lens at each moment during the deformation period and the previous moment is used as the denominator;

[0018] Calculate the ratio of the numerator to the denominator, and multiply the ratio by the basic importance of the model at each moment in the deformation time period as the deformation period importance of the model at each moment in the deformation time period;

[0019] The time period during which the model does not deform is recorded as the normal time period of the model. For each moment within the normal time period of the model, the basic importance at each moment is used as the evaluation result of the importance of the model at that moment.

[0020] The time period during which the model undergoes deformation is recorded as the deformation time period of the model. For each moment within the deformation time period of the model, the importance of the deformation period at each moment is used as the evaluation result of the importance of the model at that moment.

[0021] Preferably, the specific method for obtaining the downstream model association network of each model is as follows:

[0022] For any given model, models that come into contact with the model in the BIM construction simulation animation and that appear after the model in the BIM construction animation are classified into a first-level downstream model set, and models in the first-level downstream model set are recorded as first-level downstream models.

[0023] For any first-level downstream model, models that come into contact with the first-level downstream model and appear after the first-level downstream model in the BIM construction animation are classified into the second-level downstream model set; and models in the second-level downstream model set are recorded as second-level downstream models.

[0024] This process continues until all downstream model sets for any model are obtained, and a downstream model association network for each model is constructed in order from the highest level to the lowest level of the downstream model sets; wherein, the highest level is the first-level downstream model set, the second-level downstream model set is the next highest level, and the lowest-level downstream model set is the last downstream model set obtained by the model.

[0025] Preferably, the specific method for obtaining the degree of support of the model for other models includes:

[0026] Let any model be designated as the target model, and any model in any set of downstream models of the target model be designated as the benchmark model; based on the downstream model association network of the target model, obtain several association chains pointing from the target model to the benchmark model.

[0027] Any model in any association chain pointing from the target model to the reference model is denoted as a feature model. The model that is in contact with the feature model in the BIM construction simulation animation and appears after the feature model in the BIM construction animation is denoted as a sub-model of the feature. The sum of the contact areas between the feature model and all the sub-models of the feature model is taken as the total support area of ​​the feature model.

[0028] Based on the total support area of ​​all models in all associated chains pointing from the target model to the benchmark model, and combined with the contact area between downstream models at adjacent levels in all associated chains pointing from the target model to the benchmark model, the degree of support of the target model for the benchmark model is obtained.

[0029] Preferably, the specific method for obtaining the degree of support of the target model for the benchmark model includes:

[0030] For any target model, obtain all feature models of the target model in each association chain;

[0031] The sum of the total support areas of all feature models on each associated chain is taken as the single-chain support area of ​​the target model on each associated chain; the sum of the single-chain support areas of the target model on all associated chains is taken as the cumulative support area of ​​the target model.

[0032] The cumulative support area of ​​all target models is obtained separately, and the cumulative support area of ​​all target models is normalized. The normalized result of the cumulative support area of ​​each target model is used as the degree of support of the target model to the benchmark model.

[0033] Preferably, the specific method for determining the importance of the correction for each model at each time step includes:

[0034] Obtain the downstream model set at all levels of any model. For any downstream model set, the product of the support of each model in each downstream model set to the benchmark model and the evaluation result of the importance of each model at each time step is the result of the quadratic summation of all models in the downstream model sets at all levels as the importance correction degree of any model at each time step.

[0035] Obtain the evaluation result of the importance of any model at each time step, and use the normalized result of the sum of the evaluation result and the importance correction result as the corrected importance of any model at each time step.

[0036] Preferably, the method for obtaining the initial LOD level of each model at each time step based on the correction importance of each model at each time step includes:

[0037] The initial LOD level of the model at each time step is the floor result of the product of the model's correction importance and the preset highest LOD level.

[0038] Preferably, the specific method for assigning the optimal LOD level to each model at each time step includes:

[0039] For any model at each time step, calculate the absolute value of the difference between the initial LOD level of each model and LOD100, LOD200, LOD300, LOD350, LOD400, and LOD500 at each time step, and take the LOD level with the smallest absolute value as the optimal LOD level of each model at each time step.

[0040] Secondly, another embodiment of this application provides a BIM modeling system for a building model, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of any of the above-described BIM modeling methods for a building model.

[0041] The beneficial effects of the technical solution of this application are as follows: This application analyzes the distance between each model and the observation camera at each moment in the BIM construction simulation animation, the model information captured by the observation camera, and combines the geometric complexity and deformation state of the model itself to obtain the evaluation result of the importance of each model at each moment; then, it further obtains the degree of support of each model for subsequent models through the indirect contact area between models, and corrects the importance of each model at each moment by combining the degree of support of each model for subsequent models with the importance of subsequent models; finally, it determines the optimal LOD level of each model at each moment by the corrected importance of each model at each moment, and renders each model at each moment by the optimal LOD level of each model at each moment, thereby improving the smoothness of the BIM construction simulation animation without losing the quality of the BIM construction simulation animation. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application 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 some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 A flowchart illustrating the steps of a BIM modeling method for a building model provided in this application embodiment;

[0044] Figure 2 This is a schematic diagram of a downstream model of the model provided in the embodiments of this application. Detailed Implementation

[0045] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a BIM modeling method and system for building models proposed in this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0046] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0047] The following, in conjunction with the accompanying drawings, provides a detailed explanation of the specific scheme of the BIM modeling method and system for building models provided in this application.

[0048] Please see Figure 1 The diagram illustrates a flowchart of a BIM modeling method for a building model according to an embodiment of this application. The method includes the following steps:

[0049] Step S001: Obtain all models in the BIM construction simulation animation, the observation area of ​​the model observed by the observation lens at each moment, and the distance between the observation lens and the model.

[0050] It should be noted that BIM construction simulation animation combines 3D models with construction progress and resource information to achieve full-process visual management. Before construction, BIM construction simulation animation can be used to identify process conflicts and safety hazards, reducing the risk of rework and accidents. At the same time, it can accurately grasp the construction progress and resource allocation, thereby improving the work efficiency on the construction site. However, when creating BIM construction simulation animation, all models need to be rendered. If the LOD level of the model is too high, it will cause the model rendering to lag in long shots or panoramic shots, causing some components in the animation to suddenly simplify or disappear, affecting the visual expression of the construction logic. Especially for high LOD models such as building construction models, the rendering time may be too long. Therefore, this implementation proposes a BIM modeling method for building models. By analyzing the importance of each model in each construction stage, the LOD level of each model in different time periods is dynamically adjusted to improve the smoothness of BIM construction simulation animation.

[0051] Specifically, all construction drawings are obtained, all models are constructed based on the construction drawings, and BIM construction simulation animations are further created based on all construction models. Since the process of creating models based on construction drawings and creating BIM construction simulation animations based on models is a well-known existing technology, it will not be described in detail in this embodiment.

[0052] It should be further explained that there is an observation camera in the BIM construction simulation animation, which allows viewers to observe the entire process of the BIM construction simulation animation.

[0053] Furthermore, the observation area of ​​each model observed by the observation lens at each time step, as well as the distance between the observation lens and each model, are obtained.

[0054] Step S002: Obtain the basic importance of the model at each time step based on the observed area of ​​the model, the distance between the observation lens and the model, the volume of the model, and the number of vertices at each time step; based on the difference between the degree of volume change of the model and the degree of change of the observed area of ​​the model during deformation, and in conjunction with the basic importance, obtain the deformation period importance of the model at each time step during the deformation period, and determine the evaluation result of the importance of the model at each time step.

[0055] Based on the observed area of ​​the model observed by the observation lens and the distance between the observation lens and the model at each moment, combined with the model's volume and number of vertices, the basic importance of the model at each moment in the normal time period is obtained; based on the trend of the model's volume change when the model undergoes deformation, the trend of the observed area of ​​the model observed by the observation lens, and the aforementioned basic importance, the importance of the deformation period of the model at each moment in the deformation time period is obtained.

[0056] It should be noted that this embodiment, as a BIM modeling method for building models, specifically assigns an optimal Level of Detail (LOD) to each model in the BIM construction simulation animation at each time point. This is used to render each model in the BIM construction simulation animation at each time point, improving the smoothness of the BIM construction simulation animation without sacrificing its quality. BIM construction simulation animations contain a large number of models with varying geometric complexities. To represent the relevant characteristics of models with high geometric complexity in the BIM construction simulation animation, a high LOD level needs to be assigned to these models. Furthermore, the position of the observation camera in the BIM construction simulation animation is not fixed, and changes in the camera's position will affect the representation of each model. Therefore, it is necessary to adjust the LOD level of each model in the BIM construction simulation animation based on the relative position changes between the model and the observation camera.

[0057] Preferably, in a specific embodiment of this application, for any given moment, taking the y-th moment in the normal time period of the model as an example, where the normal time period is the time period during which the model does not deform; based on the distance between the observation lens and the model at the y-th moment in the normal time period, the observation area of ​​the model observed by the observation lens at the y-th moment in the normal time period, the volume of the model, and the number of vertices of the model, the basic importance of the model at the i-th moment in the normal time period is obtained, and the specific calculation formula is as follows:

[0058]

[0059] In the formula, L y V represents the basic importance of the model at time y in a normal time period; S represents the volume of the model. y h represents the observation area of ​​the model observed by the observation lens at the y-th time point; yrepresents the distance between the observation lens and the model at the y-th time point; D represents the number of vertices of the model; α is a preset hyperparameter, and the value of α is a positive number not greater than 0.5. This application does not impose any special restrictions. In this embodiment, α = 0.01 is used as an example to avoid the case where the denominator is 0 during fractional operations; exp() represents an exponential function with the natural constant as the base; norm[] represents the Min-Max linear normalization function.

[0060] It should be noted that the basic importance level refers to the importance of the model when it has not undergone deformation. The higher the importance level, the higher the LOD level should be assigned to the model. This represents the ratio between the volume of the model and the observed area of ​​the model observed by the observation lens at the y-th time moment. The value of h y The smaller the value, the more detailed features of the model are observed at time y in the normal time period, and the stronger the user's sensitivity to the geometric details of the model. At the same time, the more vertices the model has, the higher its structural complexity, and the higher the LOD level should be assigned to ensure the visual quality of the BIM construction simulation animation for the user. This is amplified through an exponential function. h y The reason for this calculation, compared to the impact of the number of vertices D on the importance of the foundation, is that when the model is not deformed, the detailed features have a more intuitive impact on the visual quality of the BIM construction simulation animation than the number of vertices.

[0061] It should be further explained that as the BIM construction simulation animation progresses, some models in the animation will deform during the simulation (such as the gradual spread of floor slabs and the segmented erection of columns). The deformation process of the model reflects the core activities of the construction phase, and its technological details directly affect the feasibility and safety of subsequent procedures. Moreover, the completion of model deformation is often a prerequisite for subsequent construction procedures. Therefore, when the model deforms, it needs to be assigned a higher LOD level to accurately display the relevant detailed features of the model. In addition, the deformation of the model in the BIM construction simulation animation has a deformation direction. When the deformation direction of the deformed model is perpendicular to the observation direction of the observation camera, the observation camera can more clearly present the detailed features of the model deformation process. Therefore, it is necessary to assign a higher LOD level to the deformed model, and further combine the importance of the model's foundation to obtain the importance of the deformation period at each moment in the model deformation process.

[0062] Preferably, in a specific embodiment of this application, the time period during which the model deforms is denoted as the model's deformation time period. For the i-th moment in any model's deformation time period, the importance of the deformation period at the i-th moment in the model's deformation time period is obtained. Combining the observed area of ​​the model observed by the lens at the i-th and (i-1)-th moments in the model's deformation time period, and the volume of the model at the i-th and (i-1)-th moments in the model's deformation time period, the importance of the deformation period at the i-th moment in the model's deformation time period is obtained. The specific calculation formula is as follows:

[0063]

[0064] In the formula, A i L′ represents the importance of the deformation period at the i-th time point in the deformation time period of the model; i ΔV′ represents the fundamental importance at the i-th time point during the deformation time period of the model; i,i-1 ΔS′ represents the difference between the model volume at time i and time i-1 within the deformation time period. i,i-1 This represents the difference between the observed area of ​​the model observed by the lens at the i-th moment and the (i-1)-th moment within the deformation time period.

[0065] It should be noted that ΔV′ i,i-1 ΔV′ represents the change in volume of the model between two adjacent time points, reflecting the actual degree of deformation of the model at the i-th time point. i,i-1 The larger the value, the greater the degree of deformation of the model at time i; ΔS ′ i,i-1 This represents the change in the observed area of ​​the model as seen through the observation lens, reflecting the degree of deformation exhibited by the model at time i in the observation lens, and the ratio between the two values. This represents the difference between the degree of deformation observed in the observation lens and the actual degree of deformation of the model. The larger the ratio, the less likely the deformation rate observed in the observation lens is to reflect the actual deformation rate of the model. In other words, the more parallel the observation direction of the lens is to the deformation direction of the model and the observation direction of the lens, the less necessary it is to give the model a high LOD level.

[0066] It should be further noted that if the model is in a stable state without deformation, the basic importance of the model at each moment within the normal time period will be used as the evaluation result of the model's importance at that moment; while for the model during deformation, the importance of the deformation period at each moment will be determined by combining the actual deformation and the observed deformation, based on the basic importance, as the evaluation result of the model's importance at each moment during the deformation period.

[0067] Thus, we obtain the evaluation results of the importance of the model at each time step.

[0068] Step S003: Obtain the downstream model association network of each model based on the adjacent models of each model in the BIM construction simulation animation; determine the degree of support of each model to the models in the downstream model association network based on the contact area between models in the downstream model association network of each model; and correct the evaluation results of the importance of the model at each time point based on the degree of support to determine the corrected importance of each model at each time point.

[0069] It should be noted that in the BIM construction simulation animation, the models in the subsequent processes are built on the basis of the previous process models. That is, each model provides support for the models that follow it. The more important the model that it supports, the more important the supporting model is. Therefore, after obtaining the importance of the model at each time point through step S002, it is necessary to further combine the importance of the models that follow each model in the BIM construction animation to correct the importance of the model at each time point and obtain the corrected importance of the model at each time point.

[0070] Preferably, in a specific embodiment of this application, for any model, models that are in contact with the model in the BIM construction simulation animation and appear after the model in the BIM construction animation are classified into a first-level downstream model set, and models in the first-level downstream model set are recorded as first-level downstream models.

[0071] For any first-level downstream model, models that come into contact with the first-level downstream model and appear after the first-level downstream model in the BIM construction animation are classified into the second-level downstream model set; and models in the second-level downstream model set are recorded as second-level downstream models.

[0072] This process continues until all downstream model sets for any model are obtained. A downstream model network is then constructed for each model, arranged from highest to lowest level. The highest level is the first-level downstream model set, the second-level downstream model set is the next highest level, and the lowest-level downstream model set is the last downstream model set obtained for the model. For example... Figure 2 The diagram shows a downstream model association network of a model with an n-level downstream model set.

[0073] It should be noted that, generally speaking, the larger the contact area between a model and its downstream models, the greater the support that the model provides to its downstream models. Therefore, this can be used as a basis to obtain the degree of support that the model provides to its downstream models, and then, based on the degree of support provided by the model to its downstream models and the importance of its downstream models, the importance of the model can be adjusted.

[0074] Preferably, in a specific embodiment of this application, any model is designated as the target model, and any model in any downstream model set of the target model is designated as the base model; based on the downstream model association network of the target model, several association chains pointing from the target model to the base model are obtained;

[0075] Any model in any association chain pointing from the target model to the reference model is denoted as a feature model. The model that is in contact with the feature model in the BIM construction simulation animation and appears after the feature model in the BIM construction animation is denoted as a sub-model of the feature. The sum of the contact areas between the feature model and all the sub-models of the feature model is taken as the total support area of ​​the feature model.

[0076] The degree of support of the target model for the benchmark model is obtained by combining the total support area of ​​all models in all association chains pointing from the target model to the benchmark model, and the contact area between downstream models at adjacent levels in all association chains pointing from the target model to the benchmark model. The specific calculation process is as follows:

[0077] For any target model, first obtain all feature models of the target model on each associated chain; second, sum the total support area of ​​all feature models on each associated chain as the single-chain support area of ​​the target model on each associated chain; then, sum the single-chain support areas of the target model on all associated chains as the cumulative support area of ​​the target model.

[0078] Furthermore, the cumulative support area of ​​all target models is obtained separately, and the cumulative support area of ​​all target models is normalized. The normalized result of the cumulative support area of ​​each target model is used as the degree of support of the target model to the benchmark model.

[0079] Normalization is a well-known technique in the field of data processing, and the specific process will not be elaborated here. Normalization methods include, but are not limited to, max-min normalization and exponential normalization. This application does not impose any special restrictions on the normalization method. Preferably, in this embodiment, the exponential normalization function softmax is used to normalize the cumulative support area of ​​all target models.

[0080] It should be noted that the model directly supports its first-level downstream models, but indirectly supports all its second-level and lower-level downstream models. For example, the model supports its second-level downstream models through its first-level downstream models. The larger the contact area between the model and its downstream models, the greater the degree of support the model provides to its downstream models. Therefore, by obtaining the degree of support of the model for downstream models through the contact area between the downstream model sets of adjacent levels, the evaluation results of the importance of the model can be further corrected by using the degree of support of the model for downstream models as a weight.

[0081] Preferably, in a specific embodiment of this application, for any model at time j, the modified importance of the model at time j is obtained based on the evaluation results of the importance of the model at time j and all models in the downstream model association network of the model, combined with the support degree of the model at time j for all models in the downstream model association network of the model. The specific calculation process is as follows:

[0082] First, obtain the downstream model set at all levels of any model. For any downstream model set, the product of the support degree of each model in each downstream model set to the benchmark model and the evaluation result of the importance of each model at time j is the result of the quadratic summation of all models in the downstream model sets at all levels as the importance correction degree of any model at time j.

[0083] Secondly, obtain the evaluation result of the importance of any model at time j, and use the normalized result of the sum of the evaluation result and the importance correction degree as the corrected importance degree of any model at time j.

[0084] Normalization is a well-known technique in the field of data processing, and the specific process will not be elaborated here. Normalization methods include, but are not limited to, max-min normalization and exponential normalization. This application does not impose any special restrictions on the normalization method. Preferably, in this embodiment, the importance of the model correction is calculated using the max-min normalization method.

[0085] It should be noted that the model is a prerequisite for the construction of downstream models in subsequent processes. Therefore, the more important the downstream model is and the higher the degree of support it provides to its downstream models, the more important the model is. Thus, in this embodiment, the degree of support of each model in each downstream model set is used as the weight, and the importance of the model is adjusted in combination with the importance of all downstream models to accurately assess the importance of the model.

[0086] Thus, the importance of the corrections for all models at each time step is obtained.

[0087] Step S004: Based on the importance of the correction for each model at each time step, determine the initial LOD level and the optimal LOD level for each model at each time step.

[0088] It should be noted that after obtaining the correction importance of all models at each time point through step S003, the LOD level can be assigned to the models at each time point according to the correction importance of all models at each time point. This allows for the rendering of each model in the BIM construction simulation animation at each time point, thereby improving the smoothness of the BIM construction simulation animation without sacrificing its quality.

[0089] Preferably, in a specific embodiment of this application, a maximum LOD level γ is preset. The specific value of γ can be set according to the actual situation. This embodiment does not make a hard requirement. In this embodiment, γ = 500 is used as an example. For any model at time j, the importance of the correction of the model at time j is combined with the preset maximum LOD level γ to obtain the initial LOD level of the model at time j. The specific calculation formula is as follows:

[0090] R j =round(γ×W) j )

[0091] In the formula, R j γ represents the initial LOD level of the model at time j; γ represents the preset highest LOD level; W j This indicates the importance of the model correction at time j, and round() is the round-up function.

[0092] Furthermore, the absolute values ​​of the differences between the initial LOD level of the model at time j and LOD100, LOD200, LOD300, LOD350, LOD400, and LOD500 are calculated respectively, and the LOD level corresponding to the smallest absolute value is taken as the optimal LOD level of the model at time j.

[0093] Similarly, the optimal LOD level of each model at each time point is obtained, and each model at each time point is rendered based on the optimal LOD level of each model at each time point. This improves the smoothness of the BIM construction simulation animation without sacrificing its quality.

[0094] Another embodiment of this application provides a BIM modeling system for a building model, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a BIM modeling method for a building model in steps S001 to S004.

[0095] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

[0096] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A BIM modeling method for building models, characterized in that, The method includes the following steps: Obtain all models in the BIM construction simulation animation, the observation area of ​​the model observed by the observation camera at each moment, and the distance between the observation camera and the model. There is one observation camera in the BIM construction simulation animation. The basic importance of the model at each time point is obtained based on the observed area of ​​the model, the distance between the observation lens and the model, the volume of the model, and the number of vertices. Based on the difference between the change in the volume of the model and the change in the observed area of ​​the model during deformation, and combined with the basic importance, the deformation period importance of the model at each time point in the deformation time period is obtained, and the evaluation result of the importance of the model at each time point is determined. The downstream model association network of each model is obtained from the adjacent models of each model in the BIM construction simulation animation; the support degree of each model to the models in the downstream model association network is determined based on the contact area between the models in the downstream model association network of each model; the evaluation results of the importance of the model at each time step are corrected based on the support degree, and the corrected importance degree of each model at each time step is determined. Based on the importance of each model's correction at each time step, the initial LOD level and the optimal LOD level for each model at each time step are determined.

2. The BIM modeling method for a building model according to claim 1, characterized in that, The specific methods for obtaining the basic importance of the model at each time step are as follows: The sum of the observed area of ​​the model at each time step and the preset hyperparameters is used as the denominator to calculate the ratio of the model volume to the denominator. The product of the ratio and the distance between the observation lens and the model at each time step is negatively mapped using an exponential function. The normalized result of the negative mapping and the product of the number of model vertices is used as the basic importance of the model at each time step.

3. The BIM modeling method for a building model according to claim 2, characterized in that, The method for obtaining the importance of the model at each moment in the deformation time period and determining the evaluation result of the importance of the model at each moment includes the following specific methods: The time period during which the model undergoes deformation is recorded as the deformation time period of the model; The difference between the volume of the model at each time step during the deformation period and the volume at the previous time step is used as the numerator; The difference between the observed area of ​​the model in the observation lens at each moment during the deformation period and the previous moment is used as the denominator; Calculate the ratio of the numerator to the denominator, and multiply the ratio by the basic importance of the model at each moment in the deformation time period as the deformation period importance of the model at each moment in the deformation time period; The time period during which the model does not deform is recorded as the normal time period of the model. For each moment within the normal time period of the model, the basic importance at each moment is used as the evaluation result of the importance of the model at that moment. The time period during which the model undergoes deformation is recorded as the deformation time period of the model. For each moment within the deformation time period of the model, the importance of the deformation period at each moment is used as the evaluation result of the importance of the model at that moment.

4. The BIM modeling method for a building model according to claim 1, characterized in that, The specific method for obtaining the downstream model association network of each model is as follows: For any given model, models that come into contact with the model in the BIM construction simulation animation and that appear after the model in the BIM construction animation are classified into a first-level downstream model set, and models in the first-level downstream model set are recorded as first-level downstream models. For any first-level downstream model, models that come into contact with the first-level downstream model and appear after the first-level downstream model in the BIM construction animation are classified into the second-level downstream model set; and models in the second-level downstream model set are recorded as second-level downstream models. This process continues until all downstream model sets for any model are obtained, and a downstream model association network for each model is constructed in order from the highest level to the lowest level of the downstream model sets; wherein, the highest level is the first-level downstream model set, the second-level downstream model set is the next highest level, and the lowest-level downstream model set is the last downstream model set obtained by the model.

5. The BIM modeling method for a building model according to claim 1, characterized in that, The specific methods for obtaining the degree of support of the model for other models are as follows: Let any model be designated as the target model, and any model in any set of downstream models of the target model be designated as the benchmark model; based on the downstream model association network of the target model, obtain several association chains pointing from the target model to the benchmark model. Any model in any association chain pointing from the target model to the reference model is denoted as a feature model. The model that is in contact with the feature model in the BIM construction simulation animation and appears after the feature model in the BIM construction animation is denoted as a sub-model of the feature. The sum of the contact areas between the feature model and all the sub-models of the feature model is taken as the total support area of ​​the feature model. Based on the total support area of ​​all models in all associated chains pointing from the target model to the benchmark model, and combined with the contact area between downstream models at adjacent levels in all associated chains pointing from the target model to the benchmark model, the degree of support of the target model for the benchmark model is obtained.

6. The BIM modeling method for a building model according to claim 5, characterized in that, The specific methods for obtaining the degree of support of the target model for the benchmark model are as follows: For any target model, obtain all feature models of the target model in each association chain; The sum of the total support areas of all feature models on each associated chain is taken as the single-chain support area of ​​the target model on each associated chain. The cumulative support area of ​​the target model is the sum of the single-chain support areas of all associated chains. The cumulative support area of ​​all target models is obtained separately, and the cumulative support area of ​​all target models is normalized. The normalized result of the cumulative support area of ​​each target model is used as the degree of support of the target model to the benchmark model.

7. The BIM modeling method for a building model according to claim 4, characterized in that, The specific methods for determining the importance of each model's correction at each time step are as follows: Obtain the downstream model set at all levels of any model. For any downstream model set, the product of the support of each model in each downstream model set to the benchmark model and the evaluation result of the importance of each model at each time step is the result of the quadratic summation of all models in the downstream model sets at all levels as the importance correction degree of any model at each time step. Obtain the evaluation result of the importance of any model at each time step, and use the normalized result of the sum of the evaluation result and the importance correction result as the corrected importance of any model at each time step.

8. The BIM modeling method for a building model according to claim 1, characterized in that, The method for obtaining the initial LOD level of each model at each time step based on the importance of the correction at each time step includes the following specific methods: The initial LOD level of the model at each time step is the floor result of the product of the model's correction importance and the preset highest LOD level.

9. The BIM modeling method for a building model according to claim 1, characterized in that, The specific method for assigning the optimal LOD level to each model at each time point includes: For any model at each time step, calculate the absolute value of the difference between the initial LOD level of each model and LOD100, LOD200, LOD300, LOD350, LOD400, and LOD500 at each time step, and take the LOD level with the smallest absolute value as the optimal LOD level of each model at each time step.

10. A BIM modeling system for building models, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the computer program is executed by the processor, it implements the steps of the BIM modeling method for a building model as described in any one of claims 1-9.

Images