Original Building Form
Recommended Building Form
Input Parameters to be flexed
In this Module, I upgraded my Dynamo code to include another parameter to flex and see the effect from the flexing of these combinations of input parameters on the building’s physical form, as well as its performance against the metrics that I used in the previous module - Gross Floor Area, Gross Surface Area, Gross Volume as well as two additional metrics that I will introduce in the next section. The 2 input parameters that I will be flexing are the Mid Rotation angle and Mid Height level of the building. I also included the series range of values that I will be testing and combining them as different permutations of the building (using List Cartesian Product, see below) to be evaluated against the metrics.
Chosen Metrics for Evaluation
These are the metrics I will be using to evaluate the building. Profits and Embodied Carbon are two new metrics that I am introducing in this Module Assignment. For the Profitability metric, I needed to set 4 constants for the calculation of the profitability of the building - first 2 being the cost on the lowest and highest level of the building and the second 2 being the retail price on the lowest and highest level of the building. For the Embodied Carbon metric, I used 1 constant which is the average embodied carbon in a commercial building, per floor area.
Main Evaluation Custom Node
I fed these inputs parameters and metric constants into my custom node where it will report the 5 metric results that you saw above, based on the various combinations of buildings based on the 2 flexing input parameters that were chosen.
In the custom node, this set of nodes will take in the various combinations of flex parameter iterations and update the elements in the Revit model to regenerate the new building.
These nodes will obtain the 3 parameters that we saw in the previous module. The input to element here is the output from the Transaction.End node that we see above.
Profitability Metric Code Block
This code block calculates the profits based on the Floor Area of the building which is obtained from the custom node BuildingMassFloorArea, from which it is fed through both the ComputeCost and ComputeRetailValue custom nodes and the profits calculated with outputs from both nodes, by taking retail value - costs.
Compute Cost Custom Node
The ComputeCost node works mainly by taking the given constants for costs at the lowest and highest level, as well as the total height of the building and the height between each level. Here we assume that the cost of the building increases linearly as we go up each level of the building, which is reflected in the first code block. Then, we calculate the total costs on each level by taking the product of the calculated cost at that level and the floor area of the same level. We filter null values and take the sum of that list to find the total costs of constructing that particular building form.
Compute Retail Value Custom Node
The ComputeRetailValue node works the same as the ComputeCost node except it is fed the given constants for retail value at the lowest and highest level. Here the main difference is that we assume the retail price increases exponentially with the building height, since exterior views are highly desired on the top levels of the building. Hence we take the natural log of the inputs, create the series for each level and then take the exponential value of it to derive the retail value to be charged at each level.
Embodied Carbon Metric Code Block
This code block calculates the embodied carbon of the building form, by using the ComputeEmbodiedCarbon node.
Compute Embodied Carbon Custom Node
The logic for this node is to use the given embodied carbon per floor area constant and multiply it by the various floor areas and sum it up to obtain the total embodied carbon in that building form.
The outputs from the various metrics are then combined into a list, which gives the output for me to export into an excel sheet as a summary table.
Based on the summary table, it would be easy to see which building is most suited for a developer that is looking for the highest profitability, or the least amount of embodied carbon to meet their sustainability goals.
The building forms that would generate the highest profits and lowest embodied carbon are shown below, respectively.
Building with highest profitability
Mid Rotation: 45 deg
Mid Height: 100 ft
Building with lowest embodied carbon
Mid Rotation: 15 deg
Mid Height: 150 ft
A developer that might be looking to balance both metrics might choose between a building with mid rotation of 30 deg and mid height of 100 ft (let’s call it Building A), or one with mid rotation of 45 deg and mid height of 150 ft (Building B). In comparison to the building with highest profitability, Building A would have ~25% decrease in profits and ~25% in embodied carbon while Building B would have ~32% decrease in profits and ~31% decrease in embodied carbon. Hence it seems like Building A would be preferred since the ratio of the change in profits and embodied carbon is lower for Building A than B.
Building A i.e. recommended building
Mid Rotation: 30 deg
Mid Height: 100 ft