1. 1 topic background

From Neanderthals to modern society, human beings have experienced not only the changes of the times, but also the progress of culture. Even the building industry has undergone earth-shaking changes, from caves (before 25,000 BC)-mud brick houses (8000 BC)-Dohms (500 BC)-castles (3rd century AD)-towns and houses (9th century AD).

In recent years, the construction industry has developed particularly rapidly. With the progress of science, the construction industry has changed from the traditional mode to the current open management, and it is becoming more and more scientific and technological, such as prefabricated buildings and BIM technology.

BIM (architecture? Information? Modeling) is the building information model, which is a complete, consistent and logical building information database established through digital technology [4]. BIM technology was first proposed by Autodesk Company in 2002, mainly to help realize the integration of building information. From planning and design, bidding, construction, completion acceptance, late warranty period to the end of the project, all data can be transformed into three-dimensional models.

There is another important reason for the rapid development of BIM application technology, which can effectively improve work efficiency, reduce production costs, shorten construction period and maximize benefits. Therefore, BIM application technology will be a necessary skill for every builder in the future.

Graduation design is a new way and method to show and improve BIM application skills and comprehensive quality of college students majoring in construction engineering, and it is also an important way to cultivate high-quality compound and applied construction engineering talents. The task of this project is to enable students to master BIM technology in building engineering in the preparation stage, bidding stage and construction stage. Aiming at the application of BIM technology in various stages of practical engineering projects, students have the ability to apply BIM engineering modeling and BIM to deepen design, thus consolidating their professional knowledge, enriching their horizons, expanding their thinking, improving their coordination ability in analyzing and solving problems, and making necessary preparations for future work.

Development of foreign 1.2 BIM technology

The research and application of BIM in the United States is among the best in the world. At present, BIM technology has been applied to most construction projects in the United States. Since then, various BIM associations have appeared one after another, and various BIM standards have also been introduced.

BIM technology has developed well in western countries, especially in Britain. So far, the application of BIM technology in Britain is increasing at the fastest speed in the world. By March of 20 13, PAS 1 192-2 standard was released. The standard is a part of the British government's construction strategy, aiming at strengthening project delivery management and financial management, and its main purpose is to reduce the construction expenditure of the public sector by nearly 20%-30% as a whole. According to the NBS (National Building Code) investigation report of 20 15,

By 2025, the British government will release 33% planting indicators during the day. Shorten the initial construction cost and life cycle maintenance cost, 50% of the construction period, 50% of greenhouse gas emissions and 50% of the import and export trade of building materials. From 20 10, the British National Broadcasting Corporation (NBS) began to conduct the "National Architectural Survey", and conducted NationalbiMSurvey of about 1000 construction industry practitioners in the fields of architecture, engineering and surveying. This survey on business intelligence has entered its fifth year. The survey results show that after the British government released the white paper on BIM promotion policy on 20 1 1, after about four years' efforts, the effect is remarkable.

Figure 1. 1 BIM Initiative of the United States

1.3 project overview and design requirements

The title of the author's graduation project is "Modeling Performance of Charige Primary School Comprehensive Teaching Building and Revolving Dormitory in Wushenqi". The project has a building area of 5238.28 square meters, a basement area of 2242.22 square meters, 4 floors above ground (3 floors locally), a total building height of 19.00 meters (outdoor terrace to semi-slope roof), a frame structure (steel frame locally), a roof waterproof rating of 1, a fire resistance rating of 2, and a seismic fortification intensity of 7 degrees.

In this design, BIMMAKE or Revit is used to create a civil model with drawings. In the process of model creation, BIMMAKE models can be seamlessly imported into Revit, and reverse import is not recommended. Through BIMMAKE, you can simply and quickly create a civil model, deal with the heavy surface of the model with one key, quickly draw the beam slab across the room, and quickly do the detailed design and brick arrangement.

The electromechanical model of the case project is established by MagiCAD2020 for Revit20 19 (hereinafter referred to as MC), including but not limited to pipes, fittings, accessories, equipment, supports and hangers (not less than two specialties) of various electromechanical specialties. Color matching of electromechanical pipelines, accessories and equipment according to the color matching scheme (conventional color matching or customized color matching); According to the principle of comprehensive pipeline layout, the comprehensive pipeline layout of the built electromechanical pipeline is adjusted; Optimize the cross-collision pipeline by using MC electromechanical pipeline cross-fast processing function; Use MC collision inspection to check the collision situation of electromechanical pipelines that have been optimized and adjusted, and optimize and adjust the collision position again until there is no collision between pipelines; Using MC reserved hole function, the electromechanical pipeline passes through the civil wall to reserve the hole; MC collision inspection is used to check the overall collision of the model, including the inspection between electromechanical majors and between electromechanical and civil engineering, and adjust and optimize the collision position until there is no collision.

By introducing civil engineering and electromechanical model, the effect and interaction are processed on the virtual reality design platform VDP, and the general situation and implementation process of the project are introduced appropriately, and finally displayed by BIMVR; In VDP, animation simulation is used for a system part of mechanical and electrical specialty, animation simulation is used for civil structure part, and construction technology simulation for important nodes is used. You can also use LUMION software to roam the rendering model.

This design mainly adopts practical operation methods. Through the research on the modeling performance of the comprehensive teaching building and the rotating dormitory of Charige Primary School in Wushenqi, the author has a preliminary understanding of BIM application technology, understands every process of BIM modeling, and transforms the concepts in books into practical applications.

Figure 1.2 Building elevation

The creation of 2.2. Revit model

2. 1 Preparation for Pattern Creation

Graduation design itself is a difficult and heavy work, and this time the author's design is still about the modeling and performance of BIM, which is more difficult. I have never been exposed to BIM before, and I don't even know the software in this area. Moreover, only CAD has a little foundation for professional related software, and even it is not clear which software to use for this design, so this topic is really difficult for the author. So before doing this graduation project, I made a lot of preparations. At first, I made a preliminary research and analysis of the task book, and studied electromechanical modeling with my teacher for a period of time. I also borrowed relevant materials from the library and searched relevant video materials online. I didn't start modeling until I felt that I had a certain understanding of the task book. In the initial stage of modeling, it is necessary to install software on the supporting software for modeling and performance of BIM technology. The main software is as follows:

1) guanglianda BIMMAKE；;

2) Guanglianda MagiCAD 2020 for Revit 20 19,

3) Virtual reality design platforms VDP and BIMVR；;

4)Revit 20 19；

5) Microsoft Office Word, PowerPoint and Project.

6) Other BIM related software

Figure 2. Schematic diagram of1software installation

At the same time of software installation, the author first processes the data, one is drawing processing, the other is family processing. The author's set of drawings mainly includes architectural drawings, structural drawings, HVAC drawings, water application drawings and electrical drawings. The author needs to divide the drawings of various professional wells and remove the redundant contents in the drawings to facilitate the import and modeling of drawings in the later modeling. In Chinese, clan means gathering, and so does clan in Revit. There are many clans in Revit, including every component of a building, and all these clans gather together to form a complete building. The creation of a family is also very complicated. In this design, the creation of family is not described too much, and the family that comes with the system is used directly.

After the software installation is completed, you can start modeling. The author opens Autodesk Revit 20 19 software, creates a new project template (the project template is the basic setting for building a project, just like a mold, which is composed of multiple races, and a complete project can be built on the basis of the project template), and enters the formal drawing page. After entering the interface, we need to do a very simple operation, that is, separate the project browser from the plan legend (I am used to putting the plan legend on the left and the project browser on the right). Drag the project browser to the interface edge on the right side of Revit with the mouse, so that we can build the model later.

Figure 2.2 Revit interface diagram

After setting the drawing scale, I can see four directions in the project browser on my right, and I can choose one of them at will. Then open the elevation page. After entering the elevation page, click OK, and the system will automatically switch the image page. After entering the elevation page, you need to draw multiple elevation lines according to the number and height of buildings. In the Architectural option of the menu bar, select the Elevation tool to draw an elevation.

When drawing the elevation, the author draws from left to right. The description of the elevation will appear to the right of the elevation line. When drawing an elevation from right to left, the description of the elevation will appear on the left side of the elevation line. After drawing the elevation, we need to choose the elevation line. At this time, we can see that there will be a small box on the side that does not display the mark. At this time, you can click on this small box, and the mark will appear on this side after clicking. Note that Autodesk Revit will automatically display the cue line when drawing, so as to keep the length of the marker line unchanged. After drawing the elevation according to the design floor, we click the name of the elevation. In addition to the elevation data, we also need to name the elevation as F 1, F2 ... so we have completed the establishment of the elevation. After the facade is completed, we can start to draw the grid.

Because the drawing of the author's drawings adopts the method of "picking up", the grid is chaotic and difficult to pick up. In order to reduce errors and improve efficiency, the manual drawing of the grid is adopted.

Because the axis network of this group of drawings is asymmetric, it is necessary to calculate the distance between the axes before drawing. In the Project Browser on the right side of the Revit window, select F 1 in the floor plan, and click to confirm. We will turn to the drawing page on the first floor plane. We can select "Architecture-Grid" in the tab menu at the top, and you can start drawing grids in the blanks in four directions. When drawing the axis, click the blank area and then drag it horizontally or vertically, so that we can successfully draw the first grid. When drawing a grid, you must pay attention to dragging vertically or horizontally, drawing from left to right and from bottom to top, so as to ensure the correct labeling of the grid and avoid unnecessary mistakes. Next, we can repeat the above work and draw the rest of the grid. When drawing the rest of the axis network, pay attention to the distance between the axes. We can also choose to copy or array when drawing the first line, set a distance at will, and modify the distance after drawing all the grids. When modifying the distance, first select an axis, modify the distance on the left, then select the next axis, and also modify the distance on the left, until all modifications are completed.

After we draw the axis net in one direction, we can adjust the length of the axis net uniformly and click to select an axis at will. We will find a small hollow circle under the digital label of the grid. When the mouse points to the hollow circle and a dotted line connecting all the axes appears, we can drag the hollow circle until it reaches the required length, and then stop dragging, and all the axes are elongated. After drawing the grid in one direction, we repeat the above operation to draw the grid in other directions. But after drawing the first grid, we need to change the name to A. After determining the name of the first axis, all subsequent axes will be automatically labeled according to the first rule. After drawing multiple axes step by step, you can complete the grid drawing. After drawing the grid, we need to adjust the position of the grid. We must place the grid in the direction of the four elevation symbols. If it is not in the four directions, it will affect the perspective of our 3D drawing, and we need to move it out of the grid (note that there are two parts in these four directions, so we must select them all before moving). Once the grid and elevation are completed, we begin to draw foundations, columns or other structures.

Figure 2.3 screenshot of revit direction

2.2 Model creation stage

We can build the model in the following order: foundation-constructional column-structural beam-structural plate-wall-stairs-doors and windows-sloping roof-water supply and drainage-fire protection-electricity-HVAC.

2.3 structural model and building model establishment stage

Before establishing the foundation, you must look at the drawings repeatedly, fully understand the meaning of the drawings and the owner, then determine the material, shape and buried depth of the foundation, and then start to establish the foundation model. To build a foundation model, you need to import CAD drawings first, then load the family according to the shape of the foundation (most of my drawings are independent foundations under inclined columns, but there are also a few raft foundations), and then copy and create a new type for editing. Finally, the edited foundation can be placed in the corresponding position of the drawing. After putting it away, you can go to the three-dimensional map to measure whether the foundation bottom elevation is 3.4 meters, and the elevation shortcut key is EL. The basic model is simpler than other models.

Figure 2.4 Basic model

Next, we can build structural columns, and the process of building professional models is similar. The first step is to import CAD drawings (or select linked CAD), align the drawings with the grid, and press the shortcut key AL. The second step is to observe the types of columns in the drawings, including section size, height, reinforcement and stirrup spacing. After determining all kinds of columns, you can start loading the column family, which is a cast-in-place concrete rectangular column with C30 concrete strength grade. The third step is to create new types and edit all the information of 47 kinds of frame columns. Step four, you can draw the column. In order to reduce the workload, the author adopted a simple method. First, the plan F 1 is introduced. When drawing columns, the offset of column top is modified, for example, KZ22, the elevation is 8.350- 16. 150, and columns can be drawn to the roof on the drawing 8.350. Find the corresponding position of KZ25 in F 1. When drawing, it is only necessary to change the column bottom offset and the top elevation to 8350 and 16 150 respectively, which can reduce the number of drawing imports and improve work efficiency.

Figure 2.5 List and Column Legend

Be sure to pay attention to the bottom offset when drawing columns. If the column bottom offset is not modified, the foundation will run to the column bottom, or the foundation and column are not in the same plane and deviate from the original position of the foundation, so we must pay special attention. After painting the column, the elevation of foundation bottom, column bottom and column top should be measured in the three-dimensional diagram. To prevent the column or foundation from moving.

After the column is drawn, we can start to build the model of the structural beam. We first import the plane construction drawing of the structural beam, and then use the shortcut key al to align the grids respectively. After alignment, we can see the cross section of the column, which may affect our drawing, so we can adjust the visibility of the view and uncheck the structural column to hide the column.

Figure 2.6 View Visibility

From the drawings, we can know that the beams here are cast-in-place reinforced concrete beams, and the concrete strength grade is C30. We can first find the cast-in-place concrete beam rectangle in the insert/load family. After loading, we select it in the Project Browser on the right and right-click it to select a new type. Create all beams according to the numbers in the drawing, and then edit the data after creation. Liang's data editing is relatively simple, just need to edit Liang Gao and Liang Kuan. Then draw it according to the position.

Figure 2.7 shows the structural framework.

When drawing doors and windows, use "HiBIM Civil Engineering 3. 1.0". This software can directly transform doors and windows, without building models one by one and then putting them in appropriate positions, which can well coordinate the connectivity between walls and doors and windows. First, we need to link CAD drawings, and then extract some data of doors and windows. Finally it can be generated by transformation.

Figure 2.8 Renovation of Wall Doors and Windows

Finally, you can draw other building components and establish a civil model.

2.4 Establishment of electromechanical model

We can start with the water supply and drainage of electromechanical models. First, we should be familiar with the drawings, understand every detail and fully understand them. Then start modeling.

Import a CAD drawing and press the shortcut key AL to align it. Then in the project browser on the right, we will find home-pipeline-water supply, select copy, and a water supply system 2 will appear. Then double-click it and name it "Water Supply System". Then, open the "Material" option, add a new material named "Water Supply System 1" (due to the design of water supply main, we named it "Water Supply System 1" to distinguish branch pipes, main pipes and risers), change the color to green or change the number to "0,255,0". After modification, you can choose to draw a section of pipeline in the blank. Due to the visibility and view range of the view, the author may not see the drawn pipeline. At this point, you can modify the major to be coordinated in the plan tab on the left. If not, you can observe whether Pipelines and Fittings is selected in the view visibility and select it. The last view range has four items, namely top view and section view. It must be noted here that the upper and lower paragraphs must be within two boundaries, and the upper paragraph must be higher than the lower paragraph! After all these items are changed, we can display the pipeline we drew. At this moment, we select the pipeline we just drew, click on the bottom of the pipeline property column to select the system type as "water supply system 1", then click on the edit type-pipe section and size-to create a new PSP steel-plastic composite pressure pipe with a pressure of 2.0MPa, and click OK to load the pipe fittings, including elbow, tee, cross and other water pipe fittings. The same is true for the creation of other pipelines. After creation, you can start drawing the pipeline. When drawing, we must pay attention to the elevation and diameter of the pipeline. After modifying the elevation and pipe diameter, you can draw a horizontal pipeline along the pipeline in the drawing.

The drawing of the riser needs to modify the pipe diameter first, then select the elevation of the pipeline, determine the height of the riser, modify the offset again, and double-click Apply after the modification to draw the riser. We can also confirm it in the three-dimensional diagram. Such as pipeline JL- 1, the lowest elevation of the pipeline is-1.700, DN65. The elevation of the highest point of the pipeline is between 12.300- 16.200, and it is determined to be 14.500 in combination with various factors (it can be modified if other fittings and accessories are drawn later). When drawing, we choose the position of the riser and change its first offset to-1700. After drawing from-1700, modify its offset to14500-(-1700) =16200, and then double-click "Apply" to draw the riser successfully. Then we install pipe fittings, toilets, urinals and other sanitary equipment.

The drawings of HVAC specialty and electrical specialty are similar to those of water supply and drainage specialty. Just draw according to this method.

Figure 2.9 electromechanical model shows that

Figure 2. 10 electromechanical model display