A Revit-based method and system for BIM building facade modeling.

Abstract

This invention discloses a method and system for exterior facade modeling of BIM building models based on Revit, belonging to the field of 3D modeling technology. The method includes: parsing the BIM building model; determining the category of all walls based on the parsing results; when the wall category is curtain wall or exterior wall, identifying the curtain wall or exterior wall as the exterior facade wall; when the wall category is other than curtain wall or exterior wall, generating auxiliary rooms based on the other walls, identifying the non-public walls of the auxiliary rooms, and identifying the non-public walls as the exterior facade walls; and generating the exterior facade based on all the obtained exterior facade walls. This invention achieves simple and efficient extraction of the exterior facade of a Revit BIM model, with the advantage of fast extraction speed. Extraction can be achieved through the Revit API itself, which is simple, effective, and efficient, avoiding the problems of long loading times, browsing lag, and increased system memory usage that occur when rendering park-level or city-level BIM models on web pages using WebGL.

Description

Technical Field

[0001] This invention relates to the field of 3D modeling technology, and in particular to a method and system for modeling the facade of a BIM building model based on Revit. Background Technology

[0002] With the rapid development of BIM technology, the construction of ultra-large-scale 3D scenes based on WebGL has become increasingly common and is widely used in various BIM application fields such as smart parks and smart cities.

[0003] However, for BIM models at the park or city level, which contain a large number of buildings and structures, covering multiple disciplines such as architecture, structure, interior decoration, and mechanical and electrical systems, the number of components can easily reach hundreds of thousands or even millions. When rendered on a webpage using WebGL, problems such as long loading times, browsing lag, and increased system memory usage will occur. Summary of the Invention

[0004] The present invention aims to solve the problems of long loading times, browsing lag, and increased system memory usage when rendering park-level or city-level BIM models on web pages using WebGL. To address these technical issues, the present invention provides a method and system for modeling the facade of BIM building models based on Revit.

[0005] The first aspect provides a Revit-based method for modeling the facade of a BIM building, including:

[0006] The BIM building model is analyzed using Revit, and the category of all walls is determined based on the analysis results. When the category of a wall is curtain wall or exterior wall, the curtain wall or exterior wall is identified as an exterior facade wall.

[0007] When the wall type is other than curtain wall and exterior wall, auxiliary rooms are generated based on the curtain wall, the exterior wall and the other walls, the non-public walls of the auxiliary rooms are determined, and the non-public walls are determined as exterior facade walls;

[0008] Generate the facade based on all the obtained exterior walls.

[0009] In one possible implementation of the first aspect, the BIM building model is parsed, and the category of all walls is determined based on the parsing results, specifically including:

[0010] Based on the floor attributes of all BIM building models, determine the BIM building model under each floor;

[0011] By parsing all BIM building models of the i-th floor using Revit, all walls contained in the i-th floor are determined, and the wall category attributes of each wall are obtained.

[0012] Based on the wall category attribute, determine whether each wall on the i-th floor is a curtain wall, an exterior wall, or another type of wall;

[0013] Where i = 1, 2, ..., I, and I is the number of floors.

[0014] In one possible implementation of the first aspect, generating an auxiliary room based on the curtain wall, the exterior wall, and the other walls specifically includes:

[0015] Read all positioning lines identified as the curtain wall, the exterior wall, and the other walls from the BIM building model, and convert the positioning lines into curves;

[0016] Determine whether all the obtained curves intersect, and store all intersection points;

[0017] Based on the location of each intersection point, the wall to which each intersection point belongs is cut to generate an independent closed area;

[0018] Read the floor plan topology information of each floor from the BIM building model to obtain all closed curves and determine the room location attributes of each closed curve;

[0019] Based on the room location attributes, determine whether a room has been created in each of the enclosed areas. For enclosed areas where no room has been created, generate an auxiliary room.

[0020] In one possible implementation of the first aspect, the non-public walls of the auxiliary room are identified, and these non-public walls are defined as exterior facade walls, specifically including:

[0021] For each of the auxiliary rooms, the room boundary information is obtained from the BIM building model;

[0022] The room walls are determined from the room boundary information. It is then determined whether each room wall appears repeatedly in the room boundary information. Room walls that do not appear repeatedly are identified as non-public walls.

[0023] In one possible implementation of the first aspect, the facade is generated based on all the obtained facade walls, specifically including:

[0024] Treat all exterior walls as exterior facade elements;

[0025] Obtain the attached elements of each of the exterior walls from the BIM building model, and use the attached elements as exterior elements;

[0026] Obtain the connected elements of each of the exterior walls from the BIM building model, and use the connected elements and their subordinate elements as exterior elements;

[0027] For each floor's BIM building model, in addition to facade elements, the geometric center point of each BIM element is obtained through a bounding box. Based on the geometric center point, it is determined whether each BIM element is in the room of the corresponding floor. BIM elements not in the room and their associated elements are treated as facade elements.

[0028] Generate the facade based on all facade elements.

[0029] Secondly, a Revit-based BIM building model facade modeling system is provided, including:

[0030] The wall classification unit is used to analyze the BIM building model through Revit and determine the category of all walls based on the analysis results. When the wall category is curtain wall or exterior wall, the curtain wall or exterior wall is identified as an exterior facade wall.

[0031] A room generation unit is used to generate an auxiliary room based on the curtain wall, the exterior wall, and the other walls when the wall type is a wall other than the curtain wall and the exterior wall, determine the non-public walls of the auxiliary room, and identify the non-public walls as exterior facade walls.

[0032] The facade modeling unit is used to generate the facade based on all the obtained facade walls.

[0033] In one possible implementation of the second aspect, the wall classification unit is specifically used to determine the BIM building model under each floor based on the floor attributes of all BIM building models; to parse all BIM building models of the i-th floor using Revit, to determine all walls contained in the i-th floor, and to obtain the wall category attribute of each wall; and to determine whether the category of each wall on the i-th floor is a curtain wall, an exterior wall, or another type of wall based on the wall category attribute.

[0034] Where i = 1, 2, ..., I, and I is the number of floors.

[0035] In one possible implementation of the second aspect, the room generation unit is specifically used to read all positioning lines identified as the curtain wall, the exterior wall, and the other walls from the BIM building model, and convert the positioning lines into curves; determine whether all the obtained curves intersect, and store all intersection points; based on the position of each intersection point, cut the wall to which each intersection point belongs to generate an independent closed area; read the planar topology information of each floor from the BIM building model to obtain all closed curves, and determine the room positioning attribute of each closed curve; determine whether each closed area has already created a room based on the room positioning attribute, and generate auxiliary rooms for closed areas where no rooms have been created.

[0036] In one possible implementation of the second aspect, the room generation unit is specifically used to obtain room boundary information from the BIM building model for each of the auxiliary rooms; determine the room walls from the room boundary information; determine whether each room wall appears repeatedly in the room boundary information; and determine the room walls that do not appear repeatedly as non-public walls.

[0037] In one possible implementation of the second aspect, the facade modeling unit is specifically used to treat all facade walls as facade elements; obtain the attached elements of each facade wall from the BIM building model, and use the attached elements as facade elements; obtain the connected elements of each facade wall from the BIM building model, and use the connected elements and their attached elements as facade elements; for each floor's BIM building model, in addition to facade elements, obtain the geometric center point of each BIM element through a bounding box, determine whether each BIM element is in a room on the corresponding floor based on the geometric center point, and use the BIM elements not in the room and their attached elements as facade elements; and generate the facade based on all facade elements.

[0038] This solution first performs a preliminary classification of walls, then generates auxiliary rooms from other walls for those that do not belong to curtain walls or exterior walls, thereby determining all exterior facade walls. Finally, it generates the facades, achieving a simple and efficient extraction of facades from Revit BIM models. Specifically, it boasts a fast extraction speed, which can be achieved through Revit's own API. This simple, effective, and efficient method avoids the problems of long loading times, browsing lag, and increased system memory usage that occur when rendering park-level or city-level BIM models on web pages using WebGL. It provides strong support for the smooth rendering of city-level BIM building models and also provides a basis for hierarchical streaming loading of large-scale BIM building models.

[0039] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0040] Figure 1 A flowchart illustrating an embodiment of the facade modeling method of the present invention;

[0041] Figure 2 A schematic diagram of intersecting wall cutting provided for an embodiment of the facade modeling method of the present invention;

[0042] Figure 3 A schematic diagram of an auxiliary room provided for an embodiment of the facade modeling method of the present invention;

[0043] Figure 4 A schematic diagram illustrating the determination of common walls provided in an embodiment of the facade modeling method of the present invention;

[0044] Figure 5 A schematic diagram of an exterior wall and its connected and auxiliary elements provided for an embodiment of the exterior facade modeling method of the present invention;

[0045] Figure 6 A schematic diagram of the original floor BIM model provided for an embodiment of the facade modeling method of the present invention;

[0046] Figure 7 This is a schematic diagram of a floor facade model provided for an embodiment of the facade modeling method of the present invention. Detailed Implementation

[0047] The principles and features of the present invention are described below with reference to the accompanying drawings. The embodiments described are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0048] like Figure 1 The diagram shown is a flowchart illustrating an embodiment of the facade modeling method of the present invention. This Revit-based BIM building model facade modeling method includes:

[0049] S1. Analyze the BIM building model using Revit, and determine the category of all walls based on the analysis results. When the wall category is curtain wall or exterior wall, the curtain wall or exterior wall is determined as the exterior facade wall.

[0050] It should be noted that BIM building models can be parsed using Revit's own API.

[0051] It should be understood that BIM building models can pre-store the category attributes of each wall, and the category of the wall can be determined by the category attributes. Walls other than curtain walls and exterior walls can be classified as other walls.

[0052] It should be understood that curtain walls can be tempered glass curtain walls, one-way glass curtain walls, etc., and walls can be brick walls, cement walls, etc. The types of these walls are stored as attribute values ​​in the BIM building model.

[0053] S2, When the wall type is other than curtain wall and exterior wall, generate auxiliary rooms based on curtain wall, exterior wall and other walls, determine the non-public walls of the auxiliary rooms, and define the non-public walls as exterior facade walls;

[0054] For example, auxiliary rooms can be created using the Create function.

[0055] like Figure 3 As shown, an exemplary schematic diagram of an auxiliary room is provided. The cross in the diagram represents the center of the room. Each auxiliary room consists of four walls. Common walls are not considered as exterior walls. This allows for the comprehensive and accurate extraction of all exterior walls, preventing situations where the attribute is not classified as a curtain wall or exterior wall but actually belongs to an exterior wall, thus improving the accuracy of exterior wall extraction.

[0056] S3 generates the facade based on all the obtained facade walls.

[0057] like Figure 6 As shown, taking a single floor as an example, an exemplary original floor BIM model is provided. After processing in this embodiment, the extracted facade is as follows. Figure 7 As shown.

[0058] This embodiment first performs preliminary classification of walls, generating auxiliary rooms from other walls for those not belonging to curtain walls or exterior walls, thereby determining all exterior facade walls, and then generating the facade. This achieves simple and efficient extraction of the facade of the Revit BIM model. Specifically, it has the advantage of fast extraction speed, which can be achieved through the Revit API itself. It is simple, effective, and efficient, avoiding the problems of long loading time, browsing lag, and increased system memory when rendering park-level or city-level BIM models based on WebGL in web pages. It provides strong support for the smooth rendering of city-level BIM building models and also provides a basis for the hierarchical streaming loading of large-scale BIM building models.

[0059] Optionally, in some possible implementations, the BIM building model is parsed, and the category of all walls is determined based on the parsing results, specifically including:

[0060] Based on the floor attributes of all BIM building models, determine the BIM building model under each floor;

[0061] By parsing all BIM building models of the i-th floor using Revit, we can determine all the walls contained in the i-th floor and obtain the wall category attributes of each wall.

[0062] Based on the wall type attribute, determine whether each wall on the i-th floor is a curtain wall, an exterior wall, or another type of wall;

[0063] Where i = 1, 2, ..., I, and I is the number of floors.

[0064] For example, by obtaining the WallType property of a wall, if its enumeration value is Curtain, it can be classified as a curtain wall. By obtaining the "Function" property in the wall's type attribute, if its value is "Exterior", it can be classified as an exterior wall.

[0065] Optionally, in some possible implementations, auxiliary rooms are generated based on curtain walls, exterior walls, and other walls, specifically including:

[0066] Read all LactiaonCurves identified as curtain walls, exterior walls, and other walls from the BIM building model, and convert the LactiaonCurves into Curves.

[0067] Determine whether all the obtained curves intersect (Intersect), and store all intersection points;

[0068] Based on the location of each intersection point, the wall to which each intersection point belongs is split to generate an independent closed area;

[0069] Read the PlanTopology information of each floor from the BIM building model, obtain all closed curves PlanCircuit, and determine the IsRoomLocated attribute of each closed curve;

[0070] Based on the room's location attributes, determine whether a room has been created in each enclosed area. For enclosed areas where no room has been created, generate an auxiliary room.

[0071] For example, auxiliary rooms can be created using the Create function.

[0072] like Figure 2 As shown, an exemplary schematic diagram of intelligent cutting of intersecting walls is provided. For each intersection point, the wall containing it is cut into different closed areas.

[0073] By generating auxiliary rooms using the above method, omissions or duplications of rooms can be avoided, thus making the extracted facade more accurate.

[0074] Optionally, in some possible implementations, non-public walls of the auxiliary rooms are identified, and these non-public walls are defined as exterior facade walls, specifically including:

[0075] For each auxiliary room, the room boundary information is obtained from the BIM building model;

[0076] The room walls are identified from the room boundary information. It is determined whether each room wall appears repeatedly in the room boundary information. The room walls that do not appear repeatedly are identified as non-public walls.

[0077] For example, for each room, the SpatialElementGeometryCalculator class can be used to obtain the room boundary information, then walls can be filtered from the room boundaries, and it can be determined whether each wall appears repeatedly. Figure 4 As shown, if a wall serves as the boundary of both room A and room B, then that wall is considered a recurring wall. In the statistics of all rooms, if a wall appears repeatedly, it is classified as a shared wall. Of the other walls, after removing shared walls, the remaining ones are classified as exterior walls.

[0078] Optionally, in some possible implementations, the facade is generated based on all the obtained facade walls, specifically including:

[0079] Treat all exterior walls as exterior facade elements;

[0080] Extract the attached elements of each facade wall from the BIM building model and use the attached elements as facade elements;

[0081] For example, all dependent elements can be retrieved using the FindInserts function.

[0082] It should be understood that auxiliary elements can also affect the appearance of the facade. For example, auxiliary elements include elements such as windows, doors, and openings.

[0083] Obtain the connected elements of each facade wall from the BIM building model, and use the connected elements and their subordinate elements as facade elements;

[0084] For example, the GetJoinedElements function can be used to retrieve all elements connected to the exterior wall.

[0085] Connecting elements can be decorative items connected to the exterior walls, such as columns, air conditioner outdoor units, and external balconies.

[0086] like Figure 5 As shown, an exemplary diagram of connected elements and attached elements is provided. The connected element can be a column, and the attached element can be a window.

[0087] For each floor's BIM building model, in addition to facade elements, the geometric center point of each BIM element is obtained through a bounding box. Based on the geometric center point, it is determined whether each BIM element is in the room on the corresponding floor. BIM elements that are not in the room and their associated elements are treated as facade elements.

[0088] For example, the geometric center point can be obtained through the BoundingBox, and the IsPointInRoom function of the room can be used to determine whether the geometric center point of the BIM element is within the room's boundaries.

[0089] It should be understood that BIM elements other than facade elements can include fountains, gardens, flagpoles, etc., which are separate from the main building. These elements can also be extracted as facade elements.

[0090] For example, suppose there are tables and chairs in the auxiliary room. If, after judgment, the geometric center of the tables and chairs is in the corresponding room, then they are not exterior elements and do not need to be extracted, thereby improving the extraction efficiency of the exterior.

[0091] Generate the facade based on all facade elements.

[0092] By extracting facade elements using the above method, a more comprehensive extraction effect can be obtained, and non-facade elements can be prevented from being extracted, thus improving extraction efficiency.

[0093] This invention also provides a Revit-based BIM building model facade modeling system, comprising:

[0094] The wall classification unit is used to analyze the BIM building model through Revit and determine the category of all walls based on the analysis results. When the wall category is curtain wall or exterior wall, the curtain wall or exterior wall is identified as an exterior facade wall.

[0095] The room generation unit is used to generate auxiliary rooms based on curtain walls, exterior walls and other walls when the wall type is other than curtain walls and exterior walls, determine the non-public walls of the auxiliary rooms, and identify the non-public walls as exterior facade walls.

[0096] The facade modeling unit is used to generate the facade based on all the obtained facade walls.

[0097] Optionally, in some possible implementations, the wall classification unit is specifically used to determine the BIM building model under each floor based on the floor attributes of all BIM building models; to parse all BIM building models of the i-th floor using Revit, to determine all walls contained in the i-th floor, and to obtain the wall category attribute of each wall; and to determine whether the category of each wall on the i-th floor is a curtain wall, an exterior wall, or another type of wall based on the wall category attribute.

[0098] Where i = 1, 2, ..., I, and I is the number of floors.

[0099] Optionally, in some possible implementations, the room generation unit is specifically used to read all positioning lines identified as curtain walls, exterior walls, and other walls from the BIM building model, and convert the positioning lines into curves; determine whether all the obtained curves intersect, and store all intersection points; based on the position of each intersection point, cut the wall to which each intersection point belongs to generate an independent closed area; read the planar topology information of each floor from the BIM building model, obtain all closed curves, and determine the room positioning attribute of each closed curve; determine whether a room has been created in each closed area based on the room positioning attribute, and generate auxiliary rooms for closed areas where no rooms have been created.

[0100] Optionally, in some possible implementations, the room generation unit is specifically used to obtain room boundary information from the BIM building model for each auxiliary room; determine the room walls from the room boundary information; determine whether each room wall appears repeatedly in the room boundary information; and determine the room walls that do not appear repeatedly as non-public walls.

[0101] Optionally, in some possible implementations, the facade modeling unit is specifically used to treat all facade walls as facade elements; obtain the attached elements of each facade wall from the BIM building model and use the attached elements as facade elements; obtain the connected elements of each facade wall from the BIM building model and use the connected elements and their attached elements as facade elements; for each floor's BIM building model, in addition to facade elements, obtain the geometric center point of each BIM element through a bounding box, determine whether each BIM element is in a room on the corresponding floor based on the geometric center point, and use the BIM elements not in the room and their attached elements as facade elements; and generate the facade based on all facade elements.

[0102] It should be understood that the above implementation methods are product implementation methods corresponding to the prior method implementation methods. For a description of the product implementation methods, please refer to the description of the prior method implementation methods, which will not be repeated here.

[0103] It should be understood that, without departing from the concept of the present invention, those skilled in the art can combine the above embodiments in any way, and all such combinations are within the protection scope of the present invention.

[0104] Readers should understand that in the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0105] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the method embodiments described above are merely illustrative. For instance, the division of steps is only a logical functional division, and there may be other division methods in actual implementation. For example, multiple steps may be combined or integrated into another step, or some features may be ignored or not executed.

[0106] If the above methods are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0107] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for modeling the exterior facade of a BIM building model based on Revit, characterized in that, include: The BIM building model is analyzed using Revit, and the category of all walls is determined based on the analysis results. When the category of a wall is curtain wall or exterior wall, the curtain wall or exterior wall is identified as an exterior facade wall. When the wall type is other than curtain wall and exterior wall, auxiliary rooms are generated based on the curtain wall, the exterior wall and the other walls, the non-public walls of the auxiliary rooms are determined, and the non-public walls are determined as exterior facade walls; Generate the facade based on all the obtained facade walls; Specifically, generating auxiliary rooms based on the curtain wall, the exterior wall, and the other walls includes: Read all positioning lines identified as the curtain wall, the exterior wall, and the other walls from the BIM building model, and convert the positioning lines into curves; Determine whether all the obtained curves intersect, and store all intersection points; Based on the location of each intersection point, the wall to which each intersection point belongs is cut to generate an independent closed area; Read the floor plan topology information of each floor from the BIM building model to obtain all closed curves and determine the room location attributes of each closed curve; Based on the room location attributes, determine whether a room has been created in each of the enclosed areas. For enclosed areas where no room has been created, generate an auxiliary room.

2. The method for modeling the exterior facade of a BIM building model based on Revit according to claim 1, characterized in that, The BIM building model is analyzed using Revit, and the category of all walls is determined based on the analysis results, specifically including: Based on the floor attributes of all BIM building models, determine the BIM building model under each floor; By parsing all BIM building models of the i-th floor using Revit, all walls contained in the i-th floor are determined, and the wall category attributes of each wall are obtained. Based on the wall category attribute, determine whether each wall on the i-th floor is a curtain wall, an exterior wall, or another type of wall; Where i = 1, 2, ..., I, and I is the number of floors.

3. The method for modeling the exterior facade of a BIM building model based on Revit according to claim 1, characterized in that, The non-public walls of the auxiliary rooms are identified, and these non-public walls are defined as exterior facade walls, specifically including: For each of the auxiliary rooms, the room boundary information is obtained from the BIM building model; The room walls are determined from the room boundary information. It is then determined whether each room wall appears repeatedly in the room boundary information. Room walls that do not appear repeatedly are identified as non-public walls.

4. The method for modeling the exterior facade of a BIM building model based on Revit according to any one of claims 1 to 3, characterized in that, Generate the facade based on all the obtained exterior walls, specifically including: Treat all exterior walls as exterior facade elements; Obtain the attached elements of each of the exterior walls from the BIM building model, and use the attached elements as exterior elements; Obtain the connected elements of each of the exterior walls from the BIM building model, and use the connected elements and their subordinate elements as exterior elements; For each floor's BIM building model, in addition to facade elements, the geometric center point of each BIM element is obtained through a bounding box. Based on the geometric center point, it is determined whether each BIM element is in the room of the corresponding floor. BIM elements not in the room and their associated elements are treated as facade elements. Generate the facade based on all facade elements.

5. A Revit-based BIM building model facade modeling system, characterized in that, include: The wall classification unit is used to analyze the BIM building model through Revit and determine the category of all walls based on the analysis results. When the wall category is curtain wall or exterior wall, the curtain wall or exterior wall is identified as an exterior facade wall. A room generation unit is used to generate an auxiliary room based on the curtain wall, the exterior wall, and the other walls when the wall type is a wall other than the curtain wall and the exterior wall, determine the non-public walls of the auxiliary room, and identify the non-public walls as exterior facade walls. The facade modeling unit is used to generate the facade based on all the obtained facade walls; Specifically, the room generation unit is used to read all positioning lines identified as curtain walls, exterior walls, and other walls from the BIM building model, and convert the positioning lines into curves; determine whether all the obtained curves intersect and store all intersection points; cut the wall to which each intersection point belongs based on the position of each intersection point to generate an independent closed area; read the planar topology information of each floor from the BIM building model to obtain all closed curves and determine the room positioning attribute of each closed curve; determine whether a room has been created in each closed area based on the room positioning attribute, and generate auxiliary rooms for closed areas where no room has been created.

6. The Revit-based BIM building model facade modeling system according to claim 5, characterized in that, The wall classification unit is specifically used to determine the BIM building model under each floor based on the floor attributes of all BIM building models; to parse all BIM building models of the i-th floor using Revit, to determine all walls contained in the i-th floor, and to obtain the wall category attribute of each wall; and to determine whether the category of each wall on the i-th floor is curtain wall, exterior wall, or other wall based on the wall category attribute. Where i = 1, 2, ..., I, and I is the number of floors.

7. The Revit-based BIM building model facade modeling system according to claim 5, characterized in that, The room generation unit is specifically used to obtain room boundary information from the BIM building model for each auxiliary room; determine the room walls from the room boundary information; determine whether each room wall appears repeatedly in the room boundary information; and determine the room walls that do not appear repeatedly as non-public walls.

8. The Revit-based BIM building model facade modeling system according to any one of claims 5 to 7, characterized in that, The facade modeling unit is specifically used to treat all facade walls as facade elements; to obtain the subordinate elements of each facade wall from the BIM building model and to treat the subordinate elements as facade elements; and to obtain the connected elements of each facade wall from the BIM building model and to treat the connected elements and their subordinate elements as facade elements. For each floor's BIM building model, in addition to facade elements, the geometric center point of each BIM element is obtained through a bounding box. Based on the geometric center point, it is determined whether each BIM element is in the room of the corresponding floor. BIM elements not in the room and their associated elements are treated as facade elements. Generate the facade based on all facade elements.

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