Search found 25 matches

by eddybox
Thu Apr 10, 2008 6:01 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Getting starting programming an implicit "lcp" solver?
Replies: 7
Views: 6839

Re: Getting starting programming an implicit "lcp" solver?

Jeremiah, You're confusing your physical model and your time integration scheme. Generally, you don't want your force be a function of your time step. Instead, compute your force as a function of the state (positions, velocities, etc.) of your system. Once that's clear, explicit Euler is just a sche...
by eddybox
Mon Apr 07, 2008 10:14 pm
Forum: General Bullet Physics Support and Feedback
Topic: Transforms for creating a btConeTwistConstraint
Replies: 8
Views: 11820

Re: Transforms for creating a btConeTwistConstraint

I just submitted a patch to fix some of the known problems (mostly taken from LvR's and Marcus's suggestions, thanks): http://code.google.com/p/bullet/issues/detail?id=47 It contains a fix for: - the quaternion inverse - a btHingeConstraint constructor - the btConeTwistConstraint swing calculation b...
by eddybox
Fri Apr 04, 2008 10:28 pm
Forum: General Bullet Physics Support and Feedback
Topic: Transforms for creating a btConeTwistConstraint
Replies: 8
Views: 11820

Re: Transforms for creating a btConeTwistConstraint

One more thing I just noticed. The following code at the beginning of the btConeTwistConstraint constructor is a bit odd: // flip axis for correct angles m_rbBFrame.getBasis()[1][0] *= btScalar(-1.); m_rbBFrame.getBasis()[1][1] *= btScalar(-1.); m_rbBFrame.getBasis()[1][2] *= btScalar(-1.); When usi...
by eddybox
Fri Apr 04, 2008 8:54 pm
Forum: General Bullet Physics Support and Feedback
Topic: Transforms for creating a btConeTwistConstraint
Replies: 8
Views: 11820

Re: Transforms for creating a btConeTwistConstraint

DigitalGhost, [cool model, btw] First of all, there was a bug in the btConeTwistConstraint class that Marcus Hennix found and has a fix for. I'm not sure if it made its way into version 2.67, but it wasn't in 2.66. Line 146 (or thereabouts) of btConeTwistConstraint.cpp should read: btScalar EllipseA...
by eddybox
Mon Mar 10, 2008 3:18 pm
Forum: Physics authoring tools, serialization, standards and related topics
Topic: 3D Tools/World editors for physics APIs?
Replies: 9
Views: 14704

Re: 3D Tools/World editors for physics APIs?

I will check if there is any other way we can get some resources to get freely available physics authoring tools. Thanks Erwin. A thought: although I'm not familiar with Blender, I'm wondering if it isn't a better (and perhaps easier) choice given it's existing integration of Bullet and the fact th...
by eddybox
Fri Mar 07, 2008 6:16 pm
Forum: Physics authoring tools, serialization, standards and related topics
Topic: 3D Tools/World editors for physics APIs?
Replies: 9
Views: 14704

Re: 3D Tools/World editors for physics APIs?

Well, I "spent a little time" with Scythe and NIMA. Scythe: While I found some aspects of the tool to be great (particularly the automated ragdoll creation and constraint limit visualization), I found the interface to be tricky to use (picking difficulties, and no way to name/identify your...
by eddybox
Fri Feb 15, 2008 2:15 am
Forum: Physics authoring tools, serialization, standards and related topics
Topic: 3D Tools/World editors for physics APIs?
Replies: 9
Views: 14704

Re: 3D Tools/World editors for physics APIs?

I was about to ask a similar question. Thanks, Erwin! Specifically, I'm looking at a way to author ragdolls, including joint limits (hinge and cone/twist), without reinventing the wheel. We're using Maya, so I'll check out Nima. I'm looking at Scythe as well. Looks interesting, but it seems a little...
by eddybox
Fri Nov 30, 2007 8:01 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Sumotori Dreams
Replies: 24
Views: 40361

Re: Sumotori Dreams

Thanks for your suggestions, Dirk. I'll keep them in mind...

That said, I'd rather benefit from an existing engine if it can (be minimally adapted to) support my needs. Anyone out there with experience/suggestions on getting there with Bullet, ODE or PhysX?

Thanks,
Eddy
by eddybox
Thu Nov 29, 2007 9:22 pm
Forum: General Bullet Physics Support and Feedback
Topic: Motors & Torques For Ragdolls
Replies: 5
Views: 4456

Re: Motors & Torques For Ragdolls

I'm also interested in this subject (ODE vs. Bullet for joint control).
Is Bullet really not an option for this type of problem? (That statement about the joint constraints being violated - not just the motors being too weak - is particularly disturbing.)

Thanks,
Eddy
by eddybox
Thu Nov 29, 2007 9:12 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Sumotori Dreams
Replies: 24
Views: 40361

Re: Sumotori Dreams

The balancing in Sumotori is pretty cool and fun to watch, and the getup is impressive. Anyone know what engine is being used (or is it all homegrown)? I'm starting some work on "advanced ragdolls" (ie. not just floppy rigs, but more à la natural motion), and I'm trying to decide on a phys...