Search found 10 matches

by pinballwizard
Mon May 04, 2009 2:18 pm
Forum: General Bullet Physics Support and Feedback
Topic: Bullet SWIG (Simplified Wrapper Interface Generator) 4 Lua
Replies: 3
Views: 7961

Re: Bullet SWIG (Simplified Wrapper Interface Generator) 4 Lua

Yes, I for one would be very much interested in Python bindings. Please keep us posted on the progress!
by pinballwizard
Mon Jul 30, 2007 6:27 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Jakobsen particles+Verlet -> breakable joints?
Replies: 13
Views: 14904

Another example that would be interesting would be a stack of boxes (pushing forces instead of pulling forces in a rope). Upon further reflection I realized that Jakobsen's paper suggests, due to the expense of collision detection, that collision detection and resolution only be run once per frame ...
by pinballwizard
Mon Jul 30, 2007 2:03 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Jakobsen particles+Verlet -> breakable joints?
Replies: 13
Views: 14904

Unfortunately I couldn't get the demo at http://www.gamefight.org/tensionTest/ to run on my Linux computer ("Error: Start failed: class not found: rgb2"). One question, though about your demo: did you try making the particles different masses? As I said, particles with different masses and...
by pinballwizard
Wed Jul 04, 2007 4:39 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Jakobsen particles+Verlet -> breakable joints?
Replies: 13
Views: 14904

This is only true if you iterate a single time; if you use several constraint iterations, the "forces" should propagate through the chain in a single frame.. the amount that they actually do propagate is dependent on the number of iterations and the order in which constraints are applied ...
by pinballwizard
Sat Jun 30, 2007 5:07 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Jakobsen particles+Verlet -> breakable joints?
Replies: 13
Views: 14904

Very interesting post, ewjordan... Hence the error in the pre-corrected values will be identical, and the error doesn't function as a reasonable proxy for joint tension. The real problem is that forces are transmitted through chains of connected particles in this type of simulation over time Right. ...
by pinballwizard
Thu Jun 21, 2007 1:14 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Jakobsen particles+Verlet -> breakable joints?
Replies: 13
Views: 14904

Raigan, right, your suggestion also occurred to me last night and sounds reasonable. Basically every time you are "fixing up" a constraint, you are "effectively" applying a force/impulse, so by keeping a vector sum of these position correction vectors, you are effectively keeping...
by pinballwizard
Wed Jun 20, 2007 5:01 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Jakobsen particles+Verlet -> breakable joints?
Replies: 13
Views: 14904

I think Barenbrug is explicitly solving for constraint forces, so he doesn't have a closed-form equation for the constraint force, but instead has to plug in the derivative/gradient/Jacobian/whatever-you-call-it :oops: of the constraint force into his quasi-Newton solver, and gets the constraint for...
by pinballwizard
Tue Jun 19, 2007 6:09 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Jakobsen particles+Verlet -> breakable joints?
Replies: 13
Views: 14904

Jakobsen particles+Verlet -> breakable joints?

Hi all, Recently I dusted off my 3D Jakobsen particle-based simulation code, implemented basically as Jakobsen described (embedded tetrahedrons in 3d collision geometry, barycentric coordinate/projection for collision resolution). I recently started implementing joints. To start off, I implemented a...