3D CollisionPolygon vs CollisionShape accuracy tips/help

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:bust_in_silhouette: Asked By Kio

Hopefully this is a simple resolve, with something I have overlooked.

Have been trying to get accurate collisions in a 3D project for a not overly complicated BUT not uniform mesh object. The object will be moving so have determined KinematicBody to work the best thus far… but cannot use a generated “collision sibling” on Kinematic Body… at least not without Godot complaining in the Debugger.

Have created a CollisionPolygon and noticed that I cannot get a direct contact with a RigidBody objects CollisionShape. There is always a “GAP” at the collision contact point, both in motion as well as at rest.

I could “offset” the collisions from the mesh to fake accuracy… but why should that have to happen?

I have created a demo scene and some reference images of the setup and issue they should be more useful than trying to explain here.

The Godot Scene
Enable/disable collisions as needed for comparisions

Image of result using CollisionPolygon

Image of result using bunch of CollisionShape(s)

From the github page: Images are full res. right-click and view in new tab to see whole image in browser.

Thanks in advance for any suggestions or directing me to a solution that I have not been able to find as of yet.

Must add… using Bullet Physics. Godot physics does not seem to have this problem. But would like to resolve for using Bullet for now. 4.0 may have another Physics option but does not help at the moment.

Kio | 2019-11-14 14:05

Have the same problem. Tried switching to Godot physics, it may not have such problem, but have many other.

GreyMiller | 2020-10-21 13:45