Hey @josephrocca, I actually found that Codepen example by looking at the Getting Started page too. I left a comment on the pen asking for help earlier today and then Googled an answer out of desperation and was happy to see I wasn't the only one having the issue! Your fix worked, thanks! I'm linking your work-around in my comment on the pen so others may find it as well.

This definitely seems like it could be a deterrent for people interested in using the library if the only example on Codepen isn't working- which is unfortunate, since this seems like an awesome lib.

Also, at first glance, I expected the simulation to actually be rendered and play out in a scene, and the fact that it didn't made it feel broken as well (even though it isn't). I understand the desire to keep the pen simple without importing a rendering library and add all the extra code to make that happen, that defeats the point of a "short and sweet" pen showing how to get started with the lib and without extra resources. So it probably should stay as it is besides the fix you suggested... but I'm hoping when the pen is fixed, Sébastien can also add

Check the console to see results!

I fixed the CodePen example, made it more idiomatic, and added "short and sweet" rendering without a library:

https://codepen.io/StubbornCreature/pen/dyedmKZ