Parametric & Generative Design

Parametric tools describe geometry with rules instead of drawing it, so changing a number rebuilds the model instead of forcing you to redraw it.

Grasshopper, running inside Rhino, is the reference implementation and free with a Rhino licence. Kangaroo Physics adds form-finding and physical relaxation on top of it; the Ladybug Tools add daylight, energy and comfort analysis. Dynamo does the equivalent job for Revit, aimed at automating documentation rather than finding form.

Generative site planning is the commercial end of the same idea. TestFit tests multifamily, parking and mixed-use layouts against a real site in seconds. Giraffe and Modelur work at urban scale, combining GIS data or live planning controls with massing, which is the fastest way to answer what a site can legally hold. Autodesk Forma is Autodesk’s cloud version of early-stage massing with environmental analysis built in, priced per year.

Two things to know before committing. Most of these are plugins rather than applications: they inherit the host’s price and its file format, and Rhino.Inside.Revit exists precisely because those hosts disagree. And the free ones here are free in the honest sense — Grasshopper, Dynamo, Kangaroo and Ladybug cost nothing beyond the software they run inside.

Prices are checked by hand and the drawbacks are written out.