In practice I was usually the computational designer on the team. I could generate facade options much faster than colleagues modelling by hand in Rhino, so the facade often ended up on my desk. That made me the bottleneck.

The scripts behind those options were prototypes, written under deadline for the change due that evening. There were never budget hours to clean them up and make them reusable. They were forgotten, or I opened them months later and could no longer follow my own logic. Opening a colleague's script was harder still, because everyone builds Grasshopper definitions their own way.

On the Budapest South Gate masterplan competition for Snøhetta, I wrote a script that gave dozens of buildings their own detailed facades. That variety made the plan feel like a real city, and it helped us win. It also showed me how much a reliable facade script is worth.

The facade is the most complex part of a building to model, and the part that changes most during design. Parametric design should help, but not if every iteration starts from a new prototype.

Facet is the tool I wished I had: a maintained library of facade scripts with one shared structure, that any Rhino user can run.

Thomas Jeremy Tait, founder