Bullet Tipps

`Greenlaw´ gibt ein paar Tipps für die Verwendung von Bullet Dynamics in LightWave :

– Calculate your sims in their own scene with only the items necessary for the sim; MDD the result and then use that data in your final scene
– Don’t use more polygons in your geometry than you actually need for the sim.
– For accuracy, try to use meshes that have polygons that are more or less the same size. You’ll probably need to customize the geometry for the sim.
– This is more of a Fracture tip but still related: use meshes that have polygons that are more or less the same size to get cleaner breaks, with few to zero errors. This will mean making more polygons than you probably think the object should have but it’s important if you want a valid object that sims well with Bullet.
– If you need bevels on the insides of cracks, use a edge shader like DP Edge on the inner surfaces. This way, the edges will be ‚hidden‘ until after the object breaks, and save you a lot of unnecessary extra modeling. Note that DP Edge needs clean meshes, so see the note about Fracture.
– Cloth sim is where you actually want more polygons to get realisitic folds and wrinkles. Don’t rely on Sub-D surfaces–you’ll be dissappointed because Bullet is always looking at the ‚real‘, un-subdivided mesh. The polygons should be pretty regular and about the same size as much as possible.
– Use proxy geometry for collision, and Kinematic instead of Deformable for collision wherever possible. Most of the time, it’s many times faster with nearly the same results. (It will probably wind up being more predictable too.)
– If you need to use Deformable for collision, use a proxy object. Deformable can really drag the system down when using it for collision, and a higher resolution collision object is probably doing a lot less for the simulation than you think.

There’s a bunch of other stuff I can list but I think this covers the basics. Mostly it’s just observing and understanding what Bullet is seeing and doing with what it sees, and then removing everything from the scene that Bullet doesn’t need. Anything extra is just wasting time at this stage.

*Quelle : newtek.com