Original Building Form
First Recommended Building Form
Dynamo Graph
My Dynamo graph allows for testing either a provided Revit mass family (Twisting Triangular Mass - Constant Taper) or the original mass I constructed for Module 5 (BuildingFormArrow). The overall layout is the same as in the examples. Necessary inputs are set and computed then provided to a custom node for calculating the standard and custom metrics. Metrics from that node are mapped to their respective input values and the single-objective optimization scheme is run. The best-scoring alternative is identified (either from the current run or a CSV file storing the results from a previous run) then created and panelized (using rectangular panels with resizable openings) in Revit. Panel openings and colors are set according to view quality of the Bay Bridge (a custom evaluator described later in this Design Journal entry). Larger openings and bluer panels represent higher view quality.
Custom Node: EvalInputPairsNewMetrics
This node computes and reports metrics for each of the design alternatives as shown in the examples. In addition to the three standard metrics, the node also computes custom metrics for view quality of the Bay Bridge and the solar potential of building surfaces not facing the Bay Bridge. Metrics are returned individually as functions and collectively as lists of values with the corresponding input parameters.
Custom Node: EvalViewDirectnessLinesOfSightBayBridge
Aside from the metrics calculated in the examples (namely floor area construction cost and cumulative solar insolation potential), one of the most important comparators between building forms is view quality of the Bay Bridge since an upshot from the design brief was that the building will have a good view of the bridge. View quality was thus computed as a unitless value representing view directness towards the bridge controlling for view obstruction by MIRA SF, a condominium complex between the building and the bridge. Solids were created in Dynamo to represent the bridge and MIRA SF. View directness from the building to the center of the bridge was calculated as in the examples, but in addition any lines of sight passing through MIRA SF were assigned directness scores of 0 (as were lines of sight pointed more than 90 degrees away from the bridge). This evaluator returns individual and summed directness values along with an indication of which sight lines point within 90 degrees of the bridge.
Custom Node: SolarAnalysisUsefulSurfaces
Another important metric is average solar insolation potential of building surfaces not facing the bridge since solar panels can be placed on these surfaces without obstructing view of the bridge. Solar potential is computed as in the examples (except average potential is assessed rather than cumulative because the former better estimates consistency of power production) for the roof surface and any wall panel surfaces not facing the bridge (as determined by the view quality evaluator). Analysis values are summed and returned.
Custom Node: SingleObjectiveOptimizationScheme
My single-objective optimization scheme incorporates all metrics except gross volume since volume didn't seem relevant to any of the design considerations. I wanted to incorporate construction cost as well but since it was computed in the examples I instead tried my own combination of metrics (in truth I tried to add it but I couldn't get the necessary example nodes to work). My scheme seeks to maximize view quality of the bridge and solar potential of surfaces not facing the bridge since these are both advantageous (and the latter an explicit design goal). It also seeks to minimize floor area (a proxy for construction cost) and external surface area since these are design goals. It standardizes individual metrics by mapping them from 0 to 1 (first mapping floor and surface area from -1 to 0 then multiplying by -1 in order to attribute lower values a higher score). Metrics are weighted by perceived importance: surface area is weighted 1 because it isn't clear why surface area should be minimized, floor area weighted 2 because any construction project wants to minimize cost (but not weighted higher because floor area is a very rough approximation of cost), bridge view quality weighted 5 because it’s a specific upside of the building, and solar potential weighted 10 because structures in San Francisco will likely have to be renewably-powered to stay in long-term operation given the trajectory of city, state, and federal climate policies. Remapped and weighted metrics are summed as scores for each design alternative. Designs with floor areas outside the specified range of 1.2M-1.5M SF are assigned scores of 0 since they don't meet the project requirements.
Results Table
The best-scoring design alternative has a Top Height value of 600 feet and a Top Rotation value of 270 degrees. It was recommended despite having comparatively large floor and surface areas because it is still within the permissible floor area range, has the best view quality, and has comparatively large solar potential. It thus ranks well in the three categories considered most important in the optimization scheme (the latter two weighted most heavily and the first setting scores to 0 for alternatives outside the permissible range). However, I would construct the third recommended alternative with a Top Height value of 550 feet and a Top Rotation value of 0 degrees. As can be seen in the image of the first recommended alternative, its rotation is unsightly and likely unrealistic. The third recommended alternative has no rotation and will thus be better-looking and more attainable. It may have a lower construction cost due to having less floor area and being shorter, it has lower surface area, and it has more solar potential. In the future my testing implementation with this mass family can consider a more limited range of Top Rotations (i.e. 0-180 degrees) so that all alternatives are aesthetic and realistic.