[Bf-committers] Game Engine / Physics issues
Christopher.Maddock.1 at uni.massey.ac.nz
Wed Nov 24 12:36:24 CET 2004
First, a couple of bugs in the .blend:
1. The physics tic rate Python method is setPhysicsTicRate, not
2. None of the meshes set to use polytope are suitable to use polytope, so it
is falling back to the previous method. (Check the console)
To use polytope, all the vertices in the polytope (from faces with the
collision flag set) must be from the same material. There is also a limit of
65536 vertices. When the game engine converts a mesh from blender, it sorts
the polygons by material to reduce the render state changes required to
render. The big gotcha (and the reason why in this case polytope is not
being used) is that triangles and quads create different materials.
I still think it is unrealistic - worst case you have 8 intersecting objects
with 507 faces = 16451136 face intersection tests to do (based on n^2
algorithms - should check this.)
ODE support would be really good - the major reason sumo is the main engine is
because it is the original blender engine - it's quite difficult to map
blender's physics properties to anything but solid.
On Wednesday 24 November 2004 05:27, Mal wrote:
> I've uploaded a new version of the simple falling monkey heads scene,
> now with polytopes specified for each monkey head.
> It also has a script to change the ticRate of the physics etc.
> As you can see, it's still way too buggy for real-time use.
> Have a look at this...
> Run into the stack of boxes in front of the van. Everything flies along,
> and this is using a pretty old version of Havok ( about 4 years old ).
> Solid / Sumo should be able to handle something simple like this. Am I
> setting the scene up wrong?
> Also, has ODE been dropped? I'd like to have seen SOLID for collision
> detection, with ODE for dynamics. SUMO has no-one working to update it,
> and there are quite a few developers working with ODE ( which has been
> chosen by Softimage XSi as it's physics solution, so it's a proven
> solution ).
> When the physics gets into a useable state, I'd be happy to put together
> some test scenes for it.
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Your present plans will be successful.
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