ARCH 653 BIM Projects

ARCH 653 Project 1

1 Project Overview

One World Trade Center (1WTC) is the Western Hemisphere’s tallest building, and a memorable architectural landmark for New York. It is designed by Skidmore, Owings & Merrill (SOM).

Reference: http://www.som.com/projects/one_world_trade_center

2 Modeling Process

2.1 Parametric Mass Model

Figure 1 is the parametric 3D model of the One World Trade Center (1WTC). The model can be divided into 3 parts. The first part is the first 20 stories. In the second part, there are 8 triangular planes from the 20^th floor up to 1368 feet high. The third part is the antenna, which is created by revolve in the conceptual mass. There are 4 levels in the mass. Level 1 is in the bottom of the first part. Level 2 is not only the top of the first level but also the bottom of the second part. Level 4 is both the top of the second part and the bottom of the third part. There is a trick in choosing the height of the level 3. Level 3 is in the middle of the second part so that each side of the octagon in level 3 is the midline of the corresponding triangle in the second part. I set some parameters about the height of the three parts. Apparently, the second part is the main part of the model, which is created by using the loft method in the conceptual mass. There are four different parametric diagrams in four levels. Figure 2 shows the top view of the 4 diagrams in 3D view.

Figure 1 Parametric model of 1WTC

Figure 2 Top view of the 4 diagrams

The parametric design diagram and parameters can be seen from figure 3 and figure 4. The left octagonal in figure 3 is in the initial level. It is a square without 4 isosceles triangles in corners. The right square in figure 3 has the same side length with the former one and the side length is set as a. Four sloped sides of the left octagon in figure 4 are set as d, and the length of other 4 sides are set as c. The square in figure 4 is a smaller one that rotates 45 degree from the base square and the length of the side is b.

Figure 3 Diagrams and parameters in level 1-2

Figure 4 Diagrams and parameters in level 3-4

The parameters and formulas can be seen from figure 5. There is a limitation that one side of the octagonal in level 3 cannot be controlled by the parameter c if I put the diagram in the center but the length of the site is very close to c. The sequence of operations in Revit is very important. There will be errors if you take the wrong orders.

Figure 5 Family types of the parametric model

2.2 Parametric Curtain Panel

The origin idea of the curtain panel in the first part is the panel with prismatic glass. Mock-ups demonstrated that the prisms refract and reflect light, trees and the sky by day, then shimmer at night. Figure 6 shows the parametric curtain panel 1.The glass and louvers in the curtain panel 1 can rotate well. However, after many experiments, there is still a limitation that it cannot work well in the project. I will try to figure it out later. So I created curtain panel 2 to replace curtain panel 1. There is a small triangle that can rotate in the panel. Figure 7 shows the diagram and parameters. In the second part, I created a rectangular curtain panel. Figure 8 presents the diagram and parameters.

Figure 6 Parametric curtain panel 1

Figure 7 Parametric curtain panel 2

Figure 8 Parametric curtain panel 3

2.3 Building Façade

After creating parametric curtain panels, they were loaded into the mass model. We can see the building façade in figure 9. At first, I used the normal method to divide the surface, namely setting the number of U and V Grid. However, it does not perform well which is showed in figure 10. The U Grid is not horizontal and the V grid is not vertical. Finally, I found the solution to solve the problem.

Figure 9 Building Facade

Figure 10 Wrong method

Figure 11 Right method

I set a reference plane, drawn reference lines, turned off U and V Grid, divided surface by using intersects, turned on U Grid and set the number. The sequence of these processes is vital. There is an error if I set the number of U Grid first and then use intersects. After that, I placed dimensions between each reference lines and click EQ. In addition, I placed the dimension between the first and the last reference lines. If the reference lines are used to divide the surface that one of the side is a, I will set the dimension as f. I assume the number of reference lines is n. The formula is f=a/(n+1)*(n-1). In the same way, the other dimension is set as g. The formula is g=b/(n+1)*(n-1). The diagrams, parameters, formulas are illustrated in figure 12.