Gravity Not Working

[srhyne]

I created a 4 Wheet Ext to drive on a surface created from Infraworks. The surface is a Poly surface and I linked the Gravity Direction Mesh to the surface. However, when I record the scene, the vehicle slowing falls through the surface. It's confusing because I've done this numerous times with complete success. I created a plane surface in the same scene and linked the Gravity Direction Mesh to the plane, and the car landed on the plane like it should. This tells me it's my poly surface. Might you have any suggestions or insights I could investigate?


Thanks!

[srhyne]

I was able to resolve the gravity issue but I'm still not sure if I identified the cause. Infraworks uses Open Street information and a national terrain dataset to create a scene. The scene is made up of tiled polygons that are subdivided. The roads are separate polys and they clip out the terrain where the roads intersect. In 3DS Max, I attached some of the terrain tiles to my road surface to be part of my driving surface. However, the 4 Wheel Ext car would slowly fall through the surface. My next test was to remove the tiled terrain and only use the roadway surface which reduces the polygon count significantly. I re-ran the scene and the car stuck to the surface and drove correctly. So, is the issue a polygon count or the surface to complex?

Thanks!

[Patrik Martin]

I can think of a couple of things that might be an issue.

• Terrain is not a mesh or a polygon.
• Mesh has overlapping faces which makes the model "confused".
• To many polygons used in the terrain (too heavy).
  Our usual suggestion is to make a copy of the terrain and cut out the terrain part that is needed for the animation to reduce the amount of polygons used for the calculation. This part can be made non-renderable if needed.
• Holes in the mesh or consists of multiple parts.
  Have you checked to make sure the ground does not have overlapping vertices which makes the terrain actually have holes in it? For instance if you turn on xView -> Overlapping Vertices does it show any overlapping?
• Forget to make the gravity mesh a child of the terrain.

Hope this might help.