Why does it matter to model the real terrain and real neighboring buildings?
Context changes almost every environmental result. At my site at Oxford St and Center St, the empty-site analysis showed two things I would have missed without including the surrounding buildings. In winter, the buildings across Oxford Ln shade the south edge of the site, so putting open space there would leave it in shadow for most of the day. The wind analysis also showed that the empty lot is windier than the nearby streets because there is nothing to block the wind as it moves across the site.
The parts most affected by context are sun and shadow, pedestrian wind comfort, noise, and the way the building meets the street. Without context, it would be easy to place a plaza in a neighbor’s shadow, create a wind tunnel between a new tower and the existing high-rises, or overlook the shadows the new building would cast on nearby properties.
The context data also needs to be checked carefully. When I first loaded the site, several neighboring buildings, including the high-rises to the north, were much too short. If I had not corrected their heights, the shadow and wind results would have looked better than they actually are.
Should the building adapt to the site, or the site to the building?
Sun hours and wind frequently want opposite things from the same massing.
Option 2 showed this clearly. Its narrow courts gave the best wind comfort (88%) but the worst winter sun (26% of the ground), because the same shape that blocked the wind also blocked the sun.
I think a team should break the tie by deciding priorities before looking at the results, based on the program. For housing, daylight in the units matters every day, while wind problems at ground level can often be fixed later with trees, canopies, or landscaping. So I gave daylight more weight. The design lead should make the final call, but it should happen early in concept design, while the massing is still easy to change, and with the client's goals in mind.
Forma's rapid analyses are fast because they are approximate.
You generated three proposals and recommended one.
I did not pick Option 1 first. My instinct was the Stepped L, because I thought stepping down toward campus would balance sun, wind, and scale. The analysis changed my mind, mostly through the daylight and facade sun numbers. Option 1 had 82% of its facade with good daylight, compared to 65% for Option 3.
I would have dropped Option 1 if the tower had made the plaza or the Oxford St sidewalk uncomfortably windy. It did not, since wind comfort stayed at 84%, almost the same as the empty site.
If the lot next door is built out in three years, I think my recommendation mostly holds. The active construction site is north of Center St, so a new building there would mostly sit in our shadow rather than shade us. However, a tall building there could change the wind around the tower, so I would rerun the wind analysis before moving further into design development.