GPL v3? Huge mistake. Permissive Open Source licenses are clearly winning in the intellectual marketplace. GPL v3 is particularly problematic. See for example [0].
In the context of GitHub, MIT license is the most common license. The average number of contributor for a GitHub project is also 1, and the average number of downloads are also 1. A very large portion of all projects are empty except for a license file.
In the context of Debian and downstream distrubution like Ubuntu, GPL is the most common license. GPL family of licenses cover about 80% of all packages. The average debian package looks very different from that of a average github project, has significant more contributors and users.
So who is winning the intellectual marketplace? Debian and downstream of Debian is responsible for about 67% of all web servers. The wast majority of companies in the world has chosen to run servers which primarily has GPL licensed software inside. Operative system with primarily Permissive Open Source licensed packages are a small single digit percent of the web server market.
There is no need to resort to ad hominem attacks here, this is HN and we generally try to stay above that level.
Do you anticipate the network effect dynamics of a motion capture library to look more like an operating system (Debian model) or a specialty library (Github)? I would expect it to look a lot more like the Github data, so the fact that Linux is for historical reasons tightly coupled to GPL licensing, while interesting, is probably not a good model for predicting future contributions to a newly GPL'ed motion capture library like this one.
We are not comparing the linux kernel with this library, and I am not sure what prompted the comparison. There would not be 80% GPL in Debian and downstream if the kernel was the only package that with GPL. 80% GPL mean 80% of all 30 000 software packages in the repository.
In this context I also find it relevant that Chorodata seems to have two teams, half that focus on building this tool and an other that work on real-time performances and installations that I assume is not done for free. That implies the model that this motion capture library seem to follow is similar in spirit to open core, where the revenue does not come from the tool itself but from work that is enabled by it. Such project, new and old, usually go with GPL.
I thus expect GPLv3 to be a quite suitable license for this kind of project and it is a license that many artists that use Creative Commons understand. Share the work as much as possible, invite collaboration if you want but retain some control.
The fact that the license will probably keep big companies away doesn't necessarily means that the project can't succeed. Just to name some examples on the non OS environment:
-Slic3r, the tool that virtually started the domestic 3D printing revolution. AGPL license, 8 years of heavy development, 91 contributors and more that 6000 commits on github.
-Blender, the powerful 3D creation tool. GPLv2, 25 years, now receiving good financial support from many top-tier companies and from the community.
I don't know if you took a look at the current Low-cost mocap panorama. It's an interesting environment where many changes are happening. We felt like there was a place for a community driven project.