Link to Student
Journal Entry For
Module 7 - Study Your Options
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Step 1 - Generative Design Framework
The structure I am evaluating is the same as my module 3 shelter. There are a few things that can be evaluated:
- Material Usage Efficiency
- Design Variables
- Structure Height, Width, overhang, and other dimensions
- Number of panels
- Evaluators
- Material Cost - In effect, the surface area of the shelter. The higher the surface area, the higher the cost of materials to construct the shelter.
- Space Usage - This is the volume under the structure. If the structure were to be used, the volume of space would be a good parameter to see how many can stand.
- Most Important Tradeoffs to Consider
- The two evaluators contradict one another, where a higher volume would typically lead to a higher surface area. This is a good design problem to try and maximize the volume and minimize the surface area. This is the set of parameters that I will use in the study.
- Structural Performance
- Design Variables
- Loading on the members
- Member sizes and capacities
- Evaluators
- Demand/Capacity ratios can be found to try and get the most efficient member sizes that still can hold the loads.
- Material costs are also a factor, where larger member sizes are more expensive
- Most Important Tradeoffs to Consider
- Higher loads require higher member sizes, however the cost can be optimized by increasing the size of some members, allowing others to potentially decrease. This kind of analysis can become very complicated if considering nonlinear behavior and material yielding, but is often what is used in real design to try and get optimal sizes.
- Architectural Components
- Design Variables
- Orientation compared to sun path
- Overhang height
- Evaluators
- Front facing sun time - hypothetically if people are waiting under the shelter they would be looking out. It would be uncomfortable for them to be staring at the sun.
- Visibility - if the overhang is too high the sun will again get in peoples faces but if it is too low then it inhibits visibility.
- Most Important Tradeoffs to Consider
- Doing a problem with these parameters can be complex, with there being a delicate balance between shade and visibility.
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Step 2 - Generative Design Study
- As mentioned before, the same shelter from Module 3 was used. The added sections are the pink section on the left, which hold the generative design tiles, and the bright yellow section on the right which calculates the surface area and volume of the shelter.
- The design decision that I chose is trying to maximize shelter volume, related to the usability, while minimizing the area of the exterior, which relates to the construction cost. The idea is to be able to shelter as many people as possible while keeping the cost of the materials to construct the shelter low.
- To do this generative design study, the Galapagos tool in Grasshopper was used.
- This tool can modify genome nodes and find the optimal solution based on maximizing or minimizing the fitness function. In this case there are two evaluators, surface area and volume beneath the structure. The fitness function in this case is f=SA^1.3-V and is minimized.
- The factor of 1.3 is an importance factor which helps the magnitudes of the surface area and volume be closer to each other. This helps generate a design that will optimize based on both inputs properly.
- The genome parameters that change were selected to be the height of the shelter and the height of the final overhang, two important parameters affecting the shape of the shelter.
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Step 3 - Generative Design Study Results
- Below is a screenshot of the optimized shelter. The values are in the screenshot above,
- Below are a screenshots of the Galapagos editor. In the options, “minimize” is selected and everything is left as default.
- The program was run for 53 generations, however the optimal solution was found in generation 4. The optimal value is selected, and the value of the fitness function for each step in this generation is shown on the right.
- In this program, the line graph in the center, or “Parallel Coordinate Graph,” is what shows what the values are over time, and it is linked to the values on the right to show magnitudes. The left side of the graph represents the first input(roof height) while the right side represents the second input (overhang height). In the optimal arrangement, both of the inputs are at a fairly central values, but you can see that extremes were also tested and have their own fitness values. With this information, you can see how different values of the inputs affect the value of the fitness function, and it could give insight into general values that lead to better solutions while also showing which values to avoid.
- The graph on the left is extra information that is not needed.
- Screenshots of the grasshopper logic are shown above in the Step 2 section.