Lu Tang

Step 1 - Generative Design Framework

A very brief description of the design decisions from Step 1 following the Generative Design Framework.

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  1. A very brief description of the design decisions from Step 1 following the Generative Design Framework.
  • Construction Design
    • Tradeoff : Construction Time vs Construction Cost vs WorkForce required

Design Values:

  1. Building Height
  2. Building Location
  3. Building Material

Evaluators

  1. Construction Time
  2. Construction Cost
  3. Worker force used
  • Structural Design
    • Tradeoff : Structural Resilience Behaviour vs Building Cost

Design Values:

  1. Building Height
  2. Building Location
  3. Building structural type

Evaluators:

  1. Building Drifts
  2. Building Construction Cost
  3. Building Energy Cost
  • Sustainable Design
    • Tradeoff : Building Roof insolation vs Building Cost vs Building Geometry vs Building location

Design Values: Building Geometry

  1. Building height
  2. Building width
  3. Building location(longitude and latitude)
  4. Building shape (number of sides of the polygon)

Evaluators:

  1. The material cost of walls and roof
  2. Energy cost of walls
  3. Solar insolation of the roof

Step 2 - Generative Design Study

In this study, the building’s geometry, including the building height, building width, the number of sides, and the building location, including the latitude and longitude, will be the design values. The material cost, energy cost, and the roof insolation of the building will be the evaluators of the study.

When it comes to designing a building, my primary concern will be both the cost of the building as well as the energy saving of the building. To perform a sustainable design for a large-span building which consumes a large amount of energy, we need to think about how to utilise the use of natural resources; For example, there is an increasing interest in using solar energy. There are many different ways to achieve this goal, and the utilisation of rooftop solar by using PV panels or PV films will be a good choice.

The shape and geometry of the building greatly impact the insolation on the building’s roof, since the amount of the insolation depends on the size of the roof area, and the shape of the roof surface. Also, the location of the building will have an impact on the insolation, since the daylight varies in different regions.

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The first step is setting up the input values for this study, including three categories:

  1. Changeable variables:
    1. Building height
    2. Building Width
    3. Number of slides (for the polygon shape building)
    4. Building location (longitude and latitude)
  2. Fixed variables defiend by the user:
    1. Building volume
    2. Construction cost per area for wall
    3. Construction cost per area for roof
    4. Energy cost per area for wall
    5. Energy cost per area for roof
  3. Inputs for solar analysis
    1. Starting time
    2. Ending time
    3. Grid Spacing
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The building height here is set to be between 10 to 100 metres, the width is set to be 10 to 100 metres, the number of sides is set to be between 3 to 12, and the latitude and longitude are set to be anywhere in the world (which may not be realistic).

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The next step includes using the input values from the previous step to create a polygon solid, the solid is built by using a circle whose radius is calculated by the volume of the building divided by building height as well as pi.

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After building the polygon solid, the surface areas for the roof, surface, and the ground are calculated by using codes. Here we are using the value of the normal vector of each surface to determine the category of the surface. For example, when the normal value is 1, then it means that this surface is the rooftop, since it is point up; and when the normal value is negative 1, it means that this surface is the ground, since it is always point down; also, every other surfaces that have normal vector values that are in between positive and negative 1 means that these surfaces are the wall surfaces.

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The next step is to calculate the solar insolation value by using the solaranalysis node in dynamo. The weather is determined based on the input longitude and latitude values. While the analysis surface value is based on the category of the surface which is determined in the previous step.

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The construction and energy cost of the building is simply calculated by using the surface area of each surface category times the unit cost of this type of surface for both construction cost and energy cost.

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After the cost calculation, we can then use the watch node to see the outputs of previous calculations for the construction costs, the energy cost, the wall and roof insolation.

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For a better visualisation, the building is coloured by using the geometrycolour node.

Step 3 - Generative Design Study Results

  • The screenshot of the Scatterplot or Parallel Coordinates Graph illustrating the tradeoff that you chose to model and study.
  • Provide a brief explanation of what’s being shown in the Scatterplot or Parallel Coordinates Graph and how the tradeoff being illustrated would impact the design decision. What would you do with this info?
  • An image of your Dynamo Study Graph (showing all your nodes and the connecting logic) -- You can use the File > Export Workspace As Image... command in Dynamo to save a PNG image to upload with your posting.
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Above is the scatter plot, which could show the tradeoff that we choose to model and study, including the roof isolation, the material cost, the number of slides, and the height of the building. Also, when exploring the outcomes, we have noticed that buildings located at latitude between 25-30 generally have the best roof insolation; we decided not to choose the latitude as one of the primary outcomes in the scatterplot since the latitude of the building is already related with its roof insolation.

Based on the above outcomes, polygon-shaped buildings with 6 to 8 slides have the better roof insolation behaviour, which may be because of that when the number of slides is increasing, the shape will become closer to a circle so that the area that can have sun insolation at the same time will increase. Also, we could see that, in general, material cost increases when roof insolation increases, although it may not necessarily be true. At the same time, the height of the building does not seem to have a significant impact on the roof insolation or the material cost.

Due to previous analysis, the design shown below would be a good design choice (shown as the green dot in the scatterplot). It has relatively high roof insolation, a relatively low material cost and energy cost.

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4.An image of your Dynamo Study Graph (showing all your nodes and the connecting logic) -- You can use the File > Export Workspace As Image... command in Dynamo to save a PNG image to upload with your posting.

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