Physics and very "small" objects.

Questions & Answers
1

Hello everyone,

I have found quite a few topics that discuss how units in Unity are arbitrary, unless physics are involved. In my case, I need some very small objects to behave correctly in the physics engine so I’ve modeled them to scale. Now, however, I can’t really work with them in Unity due to their small size. They are 1-2 cm in size they are so small that using the scene viewer is almost pointless.

I noted that in my searches, someone mentioned increasing gravity to offset this scale. Is there a regular formula one could use for physics that would allow allow 1m to be treated as 1cm with respects to the physics engine?

Edit: After reading information here: http://www.bulletphysics.org/mediawiki-1.5.8/index.php?title=Scaling_The_World
and here: How to scale down physics engine - Questions & Answers - Unity Discussions

For all intents and purposes… it seems like just playing a bit with gravity will be the way to go. I was hoping for something that was more an exact science, but that seems to be more trouble than it’s worth.

2

If editing gravity is not an issue, why not just scale everything up so that 1cm = 1m?

As for things being too small, perhaps coding a custom gizmo could help you see your objects in the scene view?

Depending on your situation, it might be appropriate to replace the objects with a particle generator, or to just not apply physics to them at all (since your players probably won’t care much about lots of tiny objects you can’t see yourself)