Alpaca4d is made by Marco Pellegrino, a structural engineer who wanted the rigour of OpenSees with the freedom of Grasshopper. He started it in 2020, still builds it today, and answers your emails himself.
Creator · Lead developer
“I wish to be an artist. Meanwhile, I do engineering.”
Structural engineer and researcher. Marco started Alpaca4d in 2020 and still writes most of it: the components, the docs and the examples. He has co-authored research on the parametric design of shells and geodesic domes, presented at IWSS 2023.
With code from the community, too: thank you Jaimin6196 and TomDiks.
From a side project to a plug-in that journals, theses and conference papers use and cite.
Alpaca4d starts as a Grasshopper plug-in that drives OpenSees without a line of Tcl. The first commit lands in April.
The plug-in is shared with the Grasshopper community, new contributors send code, and supporters on Patreon help keep it going.
Alpaca4d appears in a PhD thesis at the University of Catania on structural models of whole city blocks, one of the first of the publications that now use or cite it.
Alpaca4d runs on macOS too, and installs straight from Rhino's Package Manager.
Papers from IWSS 2023 use it to study Heinz Isler's shells, geodesic domes and hyperbolic paraboloid shells.
A commercial release with a free tier for small models, and a busy year: non-linear and topology optimisation, ten-node tetrahedra, linear buckling and the Explorer web app.
OpenSees is one of the most capable structural solvers there is, and it is open source. Designers should be able to use it without learning Tcl first.
Alpaca4d writes plain, documented OpenSees files. Keep them, edit them, archive them, or run them again without Alpaca4d at all.
Every component documented with a picture, every colour checked for contrast, every element checked against a benchmark.
Results should always be checked against a second finite element package. We say so up front, and we publish our benchmarks.
OpenSees, the open-source engine from UC Berkeley that does the solving. Alpaca4d is independent of it, and grateful for it.
ASDEA Software Technology, Pescara: the MPCO recorder by M. Petracca and G. Camata, and the ASDShellQ4 and ASDShellT3 shells by M. Petracca.
And everyone who sends a bug report, a paper or a picture of their model. Keep them coming.
The first people to believe in Alpaca4d, who backed it on Patreon when it was just starting.
A question, an idea, a bug, or a project you are proud of? Write to alpaca4d@gmail.com. A human answers.