Add more realistic collision models to Prius.sdf / urdf

[liangfok]

Currently, the collision models are only on the wheels. Ideally, they should also be on the body of the vehicle so it won't be possible to drive through a concrete column as shown below:

https://www.youtube.com/watch?v=w9pJrrAPCNc

[jwnimmer-tri]

@rpoyner-tri I think perhaps a collision-box model here could be helpful? I don't think the full body mesh would be. Any advice based on your other work?

[SeanCurtis-TRI]

Would we want something in the middle? Some convex shape that is a tighter fit than a box, but still an order of magnitude simpler than the visualization mesh?

[liangfok]

That would be ideal. What app would you recommend using to create such a convex shape? Blender?

[SeanCurtis-TRI]

Blender is one option; it's what I did for the iiwa. I'm more proficient in Maya (attribute that to night on to twenty years of experience) and Thor has a license that may be briefly moochable. Either way, it's maybe a 30 minute task.

[jwnimmer-tri]

I'm not entirely sure what purpose that would serve. We don't need to simulate body collisions, just acknowledge when first contact occurs. A conservative box is likely fine for that.

[liangfok]

Yes, a conservative box will likely be OK for most situations, and could be a first-spiral solution.

[jwnimmer-tri]

This doesn't seem like its necessary anymore.