I’m new to this forum and wanted to contribute to the urban designing community with the study our company made.
We were testing the usual urban design process in SketchUp against adding a simple, easy-to-use parametric urban design extension to our workflow.
We carried a study around the benefits of using the parametric approach over traditional modeling, and focused on 4 key metrics:
- design speed
- design accuracy
- errors made
- design quality
Two groups, each of 20 participants, were given a set of requirements (maximum FAR 1.5, site coverage up to 40%, etc) prompts and told to design a new development of 4ha size on a real location in Ljubljana.
The development was split into two equal-sized parts. Half of the group created design manually on part A and using a parametric approach on part B. The other half did just the opposite, designed part A using a parametric approach and part B manually.
Research test location in Ljubljana.
One additional benefit is that parameters can also describe traditional metric dimensions can’t – eg. phasing, which can then also be taken into account of the final design output.
In the first test, we compared the time needed to create building volumes that exactly match the max. allowed FAR (1.5) and site coverage (40%).
Participants using the parametric approach were able to achieve the desired requirements 3x faster, leaving them with more time to experiment with building volumes and come up with more design options.
The average time used and FAR achieved.
Creating Accurate Designs
Furthermore, we tested how difficult it is to achieve the exact FAR. Participants were asked to create a model using the traditional metric approach and asked to try and achieve a FAR of 1.5. As the images show, it was incredibly difficult and errors were as great as 40% off the mark. It also took much more time when compared to the parametric approach, which we already covered
Histogram of the achieved FAR.
The red line, representing parametric modeling has less than 10% error in every single instance. When comparing these it becomes very clear which method allows you to work more accurately.
Figure 4: Assessment of the modeling accuracy.
Make Fewer Mistakes
Next, we wanted to investigate if there would be more or fewer mistakes when comparing metric and parametric modeling.
For this part of the research, we used the distance between buildings as an error metric and wanted to see how many buildings are misplaced and are violating the zoning rules.
When using the parametric modeling approach, the number of buildings placed too close to each other was reduced significantly.
This is due to an integrated verification system. When specific parameters are exceeded, in this case, the distance between buildings, the program will alert the user about that visually. Our research showed that this proximity warning feature alone diminished the number of errors in the model from 35% to 10% (n=20).
The Modelur warning feature diminished the number of errors in the model significantly.
For the final aspect of this research, we wanted to see if working faster and more accurately has any influence on the overall quality of a design. The research showed that the end result mostly still depends on the human designer.
While the parametric design will help you finish faster, it will not make you a better designer. Nor worse, for that matter.
But it can give you more time to experiment with building volumes and create more in-depth feasibility studies. Which in the end enables you to come up with a better, more thought-out solution.
If you want to learn more about integrating a parametric urban designing approach to your SketchUp workflow, please feel free to join our live sessions, held every Thursday.