New Evaluation Metrics

One of the first things I think of when qualifying a building as “better” than another is its economic impact and its efficient and worthwhile use of space that makes people want to be in the space. Some types of metrics, such as access to natural light, views, and biophilic design features can be useful in measuring health and well being of a building as well as the economic worth of the space. One metric I chose to evaluate is directness of view and potential for biophilic design, such as incorporating a green roof and other natural features.

Geometry: Original Building Form

I began this module by using my original geometry from Module 5, the twisting rectangular tower.

I then used three different evaluators to evaluate metrics for the building test forms used in Module 5, in addition to the metrics found in Module 5, (Gross Floor Area, Gross Surface Area, and Gross Volume).

Directness of View Evaluation

I first used a custom nodes to create normal vectors that extended from each of the panelized wall surfaces. Then I used the custom node used in the examples called PanelNormals.AllPointOutward to make sure that all the vectors would be aligned coming out from the panels of the building in order to find the correct line of sight. I also used another custom node called BuildingForm.SelectWallSurfaces in order to select just the exterior walls of the parametric form and then panelize it.

Once the lines of sight were drawn, I wanted to make sure that the users of my building would have access to views and daylight that would promote well being and productivity. Therefore, I wanted to make sure that these views and benefits would not be blocked by other buildings or structures that may be around my building. I placed several other masses around the building and then checked which lines of sight intersected with these objects. Finally, I checked how many of theses lines of sight did not intersect the masses as a measurement of the directness of views for my structure. I encapsulated all of the above logic into a single custom node called CreateLinesofSight. This custom node was used in my new evaluator node, which I updated to include the evaluation inputs needed for the CreateLinesofSight custom node.

Biophilic Design Potential Evaluator (Green Roof Potential and Cost)

In order to measure biophilic design potential, I used the custom nodes used in the class for solar potential for all building surfaces. I have learned a bit about solar potential and photovoltaic systems in a different course I am taking right now, and was interested in thinking about the intersection between solar energy generation and green roofs. I did some research and there is an emerging field of green technology energy which is working to combine the benefits of solar panels and green roofs into one combined feature. The combination of a green roof with solar has many benefits such as the cooling effects of the plants to the solar panels which may overheat in certain conditions and benefits to roof drainage and other building envelope conditions. Both a green roof and solar panels need plenty of direct sunlight to work well.

In order to evaluate this type of metric, I built upon the custom nodes from the Roof Solar module examples. I wanted to know the cost of the green roof as based on the roof area. I made a custom node called GreenRoofCost based on the research that a bio-solar green roof typically costs around $25,000 to $35,000 per 1,000 square feet (assumed $35/square foot).

Solar Nodes:

Green Roof Cost Custom Node:

Evaluation and Testing

Then, I integrated these custom nodes into my testing node logic and reported the new evaluation values for each of my test cases. I was able to output and export the testing results, which are shown below. For my testing node, I had to add the three evaluator nodes I made and all the inputs necessary for each of these. For my Green Roof Cost node I also had to make sure to use the changing Building Height input rather than a constant Building Height Input. This generated one large list that was exported to Excel for each case.

Optimization Scheme

As stated above, the two evaluation metrics I added to my original structure was directness of views and biophilic potential. Having desirable views and unblocked lines of sight from the majority of the building raises its market value and would bring in more revenue for the building. However, having a green roof and solar panels can greatly decrease the energy usage of a building over time and can decrease overall cost of the building in the long run. These two metric interact with one another as the views available from the building go hand in hand with the solar green roof potential. The more that the structure is blocked by other masses, the less solar potential and the less views are available. The main trend was to maximize both of these metrics the structure needed to be much larger than the masses surrounding it.

The goal of my optimization scheme is to maximize roof solar potential and minimize green roof cost, and maximize directness of views. I used a custom node adapted from the Modules to build my optimization scheme which assigned each metric a weighted value using linear interpolation and then summed the values of these normalized “scores”.

The final weighted combined scores for each tested option are shown below, with the top 3 choices shown in green. The darkest option is the “best” option. As seen, this option features a low cost for the green roof while having one of the highest directness of views values and the highest average insolation potential from the solar analysis. A score of 0 was designated to the design option did not meet the constraints of 1,200,00-1,700,000 square feet.

Full Dynamo Script:

Final Building Form with Shaded Surfaces: