ARCH655 - Parametric Modeling in Design_ Project 2_ 2015 Spring
Objective
Previous
project dealt with active building modeling for adaptable facades. The limitation
of the project was that individual panel could not have independent movement.
Thus, the goal of project 2 to is to develop a method for active building with
adaptable facades which can response to climate changes independently integrating
with daylighting analysis and genetic algorithm.
Modeling
To
conduct daylighting analysis, base case is developed based on previous modeling
method. Figure 1 shows a base case for this project. Each panel has different thickness
meaning that the opening ratio of each panel varies. Figure 2, 3 and 4 shows
thickness of each panel and opening ratio. The opening ratio can be defined
based on a list of the values. In addition, the use of python is more efficient
way in order to define the independent opening ratio (figure 5).
Fig 1
Fig 2
Fig 3
Fig 4
Fig 5
By
using Ladybug in Grasshopper, the Sun path can be easily integrated with the
opening ratio so that the incident angle of each panel can be calculated automatically.
This angle is employed to define opening ratio. Figure 6 shows the Sun path in
Abu Dhabi and the Sun’s vector at 5pm Dec 21, and figure 7, 8, and 9
demonstrates the openings of the facades at 9 am, noon, and 5 pm Dec 21. The movement
of the facades can be changed based on the Sun’s movement.
Fig 6
Fig 7
Fig 8
Fig 9
Daylighting
Analysis
Figure
10 shows daylighting study with fully closed facades using Diva. By integrating
the Sun path and daylighting, the daylighting analysis of the proposed method
can be conducted simultaneously (figure 11 and 12).
Fig 10
Fig 11
Fig 12
Optimization
Based
on the results of daylighting analysis, the opening ratio of each panel can be optimized.
In case of independent variables, the number of panel can be the number of
variables. In this study, the objective is to maximize the number of
illuminance nodes range from 300 lx to 1500 lx at 5 pm Dec 21 in Abu Dhabi. Figure
13 shows the result of optimization. However, this is not a good way due to a
large number of variables. To reduce the number of variables, two variables are
used in order to develop pattern of the facades (figure 14).
Previously, a BIM-based parametric model of the Al Bahar Towers was developed by using Dynamo, a visual programming environment for parametric modeling in Revit. In this project, a parametric model of the Towers are also developed by utilizing Grasshopper, a visual programming environment for Rhinoceros developed by Robert McNeel & Associates. First, the proposed Grasshopper nodes describe the development of parametric relationship for floor plan, structure, and active shading devices like previous project.
Project Background
The Al Bahar Towers, designed by Adeas, was constructed in 2011. Figure 1 shows the floor plan of the building.
<Fig.1 Floor plan of Al Bahar Towers>
Parametric Modeling
Floor Plan
Parametric relationship of the floor plan are made up of regular tringles and circles. Figure 2 is Grasshopper nodes for floor plan, and Figure 3-7 represents how the edge of floor plan can be drawn.
<Fig. 2 GH node for floor plan>
<Fig.3 Floor plan process 1>
<Fig.4 Floor plan process 2>
<Fig.5 Floor plan process 3>
<Fig.6 Floor plan process 4>
Mass Model
Various sizes and Z values make multiple curves of floor plan in order to follow original design of the building, then, the mass is created by using “loft” node in Grasshopper (Figure 7 and 9). Based on the mass model, “contour” node serves as creating different sizes of slabs which can be manipulated automatically (Figure 9).
<Fig.7 >
<Fig. 8 Mass>
<Fig. 9 different sizes of slabs >
Surface Analysis
As shown in Figure 10, the curve is developed using a G2 (Curvature Continuous). Figure 11 shows Curvature and ZEBRA analysis to understand surface’s smoothness.
<Fig.10 G2 _Curvature Continuous>
<Fig.11 Surface analysis>
Parametric Shading Devices
Even though the original set of shading devices consists of regular hexagons, in this project, a rectangle set is employed as a basic panel because Lunch box does not provides regular hexagon paneling. The basic set of parametric shading devices is started with 8 points in order to represent its 3-dimensional movement (Figure 13). This is a good way to deal with 3D paneling regardless of the shape of surface such as free form NURBS surfaces. Figure 13-14 shows the modeling process of the shading devices. Figure 15 represents variation of it, and the thickness of 3D panel is directly linked to circles which can control the opening size.
<Fig.12 8 points GH node for paneling>
<Fig.13 Paneling process 1 of 8 points >
<Fig.14 Paneling process 1 of 8 points >
<Fig. 15 Variation of opening size>
Paneling (Curtain Wall & Shading devices)
This section shows how curtain wall and shading devices can be applied to a NURBS surface (Figure 16). Lunch Box, a plug-in for exploring paneling in Grasshopper, is used to develop curtain wall and obtain 8 points for shading devices. Three different surfaces are created: inner surface will be a curtain wall, and others (green color surfaces) will provide information of 8 points of each panels. Figure 17 represents two surfaces for the shading devises and 8 points of individual panels, Figure 18 shows overall shape of parametric shading devices. In terms of its parametric relationship, distance between two NURBS surface determines opening size of shading devices (Figure 20). Based on the result of paneling, 8 points also can be used to develop a parametric frames for curtain wall ( Figure 19).
<Fig.16 GH for curtain wall>
<Fig.17 Three layers for building components>
<Fig.18 Paneling for kinetic facades using 8 points>
<Fig. 19 Paneling for curtain wall using 8 points>
<Fig.20 Variation of facades>
Structure
This building has a unique structure shape (figure 22). The provided points by using Lunch Box can be used to develop the parametric structural shape through data management. As shown in Figure 22, the structural variation is created based on the number of V direction. This means whenever the change of V direction is occurred, the shape of curtain wall, structure, and shading devices is updated automatically.
<Fig.21 GH for parametric structure>
< <Fig.22 Variation of structure>
Assembly
This model has three parts: curtain wall, structure, and shading devices (Figure 23). All parameters of them can be updated whenever building form and the number of panels is changed.
<Fig.23 Overall assembly of building component>
Parametric Parasol
This is an additional model for parametric parasol by using similar design method (Figure 24). Basic shape of the parasol consists of triangles. The shape of combined triangles can be manipulated by using Kangaroo Physics, a physics engine for Grasshopper. This can be installed outside of building to provide occupants with comfortable outside environment.
<Fig. 24 Parametric parasol>
References
CTUBH 2012. CTBUH 11th Annual Awards - Oborn & Chipchase, “Al Bahar: Innovating the Intelligent Skin”http://www.youtube.com/watch?v=-SSRUlCLUI4.Linn, Charles. Kinetic architecture: design for active envelopes. Images Publishing, 2014.http://www.food4rhino.com/?ufhhttps://www.youtube.com/watch?v=BSEVoFi9MpQ
“Enhanced Parametric Modeling with Dynamo in Revit”
1. Introduction
To develop more complicated parametric modeling, Dynamo which is a visual programming language for parametric modeling was developed. As a case study of its application, this project demonstrates how BIM model can be developed using a visual programing. Al Bahar Towers is the new headquarters of the Board of Investment of Abu Dhabi (Abu Dhabi Investment Council) designed by Aedas. The innovated façade system allows the building to create flexible movement based on the Sun’s movement. To develop this system in Revit, the incidence angle is applied to guide the size of openings.
2. Limitation of previous work.
Although parametric relationship of geometry was developed using Revit, just one parameter was used to control the size of openings. This means that the facade could not have different shapes and size of opening. Or, it is necessary to put the parameter manually. Thus, the goal of this project is to develop a parametric relationship between opening size and the incidence angle on the surfaces.
3. Solar Angles
Incident angle is the angle between the beam radiation and a normal to the surface. This can be a guideline to decide the opening size of the façade. To calculate the incidence angle, information about the movement of the Sun is required. This enables designers to decide the annual shape of façade.
4. Dynamo_A Visual Programming Language for Parametric Modelling
5. Case Study
Opening Size Example 1
Opening Size Example 2 (focusing on specific latitude and month)
6. Future work
To achieve precise results, more detailed range of incidence angle needs to be developed. Additional variables such as solar radiation, daylight and view analysis should be considered.
