A while back I encountered a bug in Unity where adding parts (that had a mesh collider) in a particular order to a construction would cause physics collisions between some parts to fail.  This would break the construction mechanic from then on as I rely on getting collision callbacks to know when parts are positioned appropriately for attachment.

Well, as far as I can tell this has been fixed as of the latest Unity release!  I didn’t get any update on the bug report I submitted, so perhaps it was fixed in relation to some other bug, either way it seems to be sorted now which is awesome.  Here’s hoping I don’t find any other similar issues…

But…of course there’s always something else to worry about!  I’ve recently noticed an odd behaviour where long, thin rigidbodies (such as axles) that have angular velocity around their long axis, tend to completely lose that angular velocity when rotated around other axes.  It’s like a massive braking force is applied to their rotation.  So I need to do some experimentation to figure out if there’s anything I can do to mitigate this (perhaps by fudging the inertia tensor or mass).