[ODE] Trimesh question
xreg at centrum.cz
Sat Sep 23 09:06:14 MST 2006
I have a problem which I am not able to fix. When creating trimesh,
there is no needed to support normal vectors as I can read in the wiki
manual. But will the trimeshs behave the same if I let the ODE to hendle
the normals itself or if I support the face normals? What are the
normals for? Is it possible that if I make the mesh with inverted
normals, that the collisions will be different?
I am asking because I have a problem with trimesh, but I cannot find a
solution, so I am thinking about the normals now... I made a video about
it, you can dowload it below.... I made some cars, every car is a body
with 4 cylinders for wheels connected to car-body with hinge2.
When I use simple BOX geom for car's body, the colisons looks like in
video 1. When I use the trimesh for car body (the trimesh is the same
like in the car rendered in video), the collisions look strange like in
video 2 - the cars are "kicking hard" to themself when touched. It's
obvious from the movies, it's hard to explain.
When I "tune" the contact-cfm and erp, it's little bit better (I set the
worse cfm and erp in purpose for the video) but it's never good enough
like in video-1 when just a box geom is used. I explain it to myself
that it's exactly because of setting ERP and the "correcting force" when
two bodies are overlapping, but I am not sure and I don't know even how
to "fix" it. So is it possible to fix this problem somehow?
And I have another question :) : A simple box geom for a car is not good
enough for the car body, but instead of using trimesh body, I would use
a couple of small boxes for representing the body, it would be about 20
or 50 or even 100 boxes per a body. Do you think it's applicable to
represent a object in scene with this amount of simple geoms? Can ODE
handle it and wouldn't it be even faster than represent it with a
low-poly-trimesh (with about the same number of triangles, say)?
VIDEO1 (box geom):
VIDEO2: (trimesh geom)
Thanks for your suggestions.
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