Search found 74 matches

by SynapticBytes
Thu Feb 27, 2014 7:16 am
Forum: General Bullet Physics Support and Feedback
Topic: Compile error on Android with #include <new>
Replies: 0
Views: 1449

Compile error on Android with #include <new>

I was compiling 12 months ago for android fine, but have updated to the latest tools, and now getting compile errors wherever "#include <new>" is being used in teh bullet headers, such as btAlignedObectArray #define BT_USE_PLACEMENT_NEW 1 .... #ifdef BT_USE_PLACEMENT_NEW #include <new> //for placeme...
by SynapticBytes
Thu Feb 20, 2014 8:02 pm
Forum: General Bullet Physics Support and Feedback
Topic: using soft body for clothing simulation
Replies: 4
Views: 3666

Re: using soft body for clothing simulation

I'm still working through my own implementation of softbodies, so don't have a definite answer, but one hack I had to do on a tablecloth to minimise penetration was create a large collision margin. Not the best answer to the question! as it looks a bit like the tablecloth has a bubble of air under i...
by SynapticBytes
Wed Feb 19, 2014 8:48 am
Forum: General Bullet Physics Support and Feedback
Topic: Does softbody friction work
Replies: 2
Views: 2183

Re: Does softbody friction work

This is funny. A year to the day I'm still looking at the same problem, and googling for an answer, I come across my original issue :)

Anyone got any updates? Does kDF do anything, or not?
by SynapticBytes
Mon Feb 17, 2014 8:59 am
Forum: General Bullet Physics Support and Feedback
Topic: generateBendingConstraints with softbodies
Replies: 2
Views: 2098

Re: generateBendingConstraints with softbodies

So did anything ever get put in for this? I'm guessing not, as my Shiva Bullet plugin is taking 200ms to create the bending constraints for a 600 vertex model. Is there any other options to improve performance? I've seen a couple posts talking about pose matching, but that's not the best solution my...
by SynapticBytes
Wed Feb 05, 2014 7:52 pm
Forum: General Bullet Physics Support and Feedback
Topic: FPS dropped significantly after adding Constraints
Replies: 9
Views: 4715

Re: FPS dropped significantly after adding Constraints

Are you only adding one constraint in total, or one constraint per object?

It seems unusual, as I have a sample scene with one of every constraint running, noticeable performance change, but there is only 2 objects per constraint.
by SynapticBytes
Tue Feb 04, 2014 8:18 pm
Forum: General Bullet Physics Support and Feedback
Topic: Rolling spheres turning into zombie spheres
Replies: 7
Views: 5263

Re: Rolling spheres turning into zombie spheres

Normal friction does not work on a sphere, as there is only a single contact point. You need at least 2 contact points for normal friction to have an effect. This is where rolling friction comes in, so for a sphere this is what you should be using, and yes, you need to set it on both bodies in conta...
by SynapticBytes
Mon Feb 03, 2014 2:19 am
Forum: General Bullet Physics Support and Feedback
Topic: Softbody response varies greatly with timestep
Replies: 3
Views: 2301

Re: Softbody response varies greatly with timestep

Try changing iterations by the same amount (2x, 3x) and you should see similar effects. But if you go to 5-6x (substep frequency or iterations), it should start leveling out. If that is indeed what you see, it's just that the error between the points is too great for a default simulation parameter ...
by SynapticBytes
Mon Feb 03, 2014 12:06 am
Forum: General Bullet Physics Support and Feedback
Topic: Softbody response varies greatly with timestep
Replies: 3
Views: 2301

Softbody response varies greatly with timestep

I am testing my bullet plugin with a multifaceted, amorphous rocky blob shape. I drop it onto the top of a set of stairs, then let it roll down and bounce into a wall at the bottom. I am wondering why, simply changing the simulation timestep greatly changes the response of the object. At a timestep ...
by SynapticBytes
Sat Feb 01, 2014 12:12 am
Forum: General Bullet Physics Support and Feedback
Topic: Overheads for using btSoftRigidDynamicsWorlds
Replies: 0
Views: 1152

Overheads for using btSoftRigidDynamicsWorlds

I'm trying to implement a Bullet plugin for Shiva3D and am up to implementing soft bodies. Because I don't know until runtime whether the users wish to create soft bodies or not, I am currently creating my physics world as a btSoftRigidDynamicsWorld, even if the user is only using rigid bodies. Just...
by SynapticBytes
Mon Feb 18, 2013 12:36 am
Forum: General Bullet Physics Support and Feedback
Topic: Softbody inoperative parameters
Replies: 0
Views: 1050

Softbody inoperative parameters

Following on from my question about Softbody friction, I'm finding lots of parameters that don't seem to do anything, except get serialized out again. I may be missing something, as posts like this one http://www.bulletphysics.org/Bullet/phpBB3/viewtopic.php?f=9&t=6446&p=22879&hilit=kCHR#p22879 and ...
by SynapticBytes
Sun Feb 17, 2013 11:45 pm
Forum: General Bullet Physics Support and Feedback
Topic: Does softbody friction work
Replies: 2
Views: 2183

Re: Does softbody friction work

So no one has used friction with softbodies? Here's the places I can find m_friction referenced in the softbody code, but m_friction is not set from kDF. Can anyone help identify where it comes from? When I debug this code and check these values, they are always 0. void btSoftBody::CJoint::Solve(btS...
by SynapticBytes
Sun Feb 17, 2013 11:37 pm
Forum: General Bullet Physics Support and Feedback
Topic: Object stuck once it stops.
Replies: 3
Views: 1374

Re: Object stuck once it stops.

It may not be an activation issue, although that's a good place to start. I've had some issues with shapes getting locked together, usually objects which may have thin dimensions in given axis, or with the world setup parameters not optimal for the shapes (e.g. a 2D world).
by SynapticBytes
Sun Feb 17, 2013 11:35 pm
Forum: General Bullet Physics Support and Feedback
Topic: Object falls through btBvhTriangleMeshShape
Replies: 2
Views: 1503

Re: Object falls through btBvhTriangleMeshShape

How fast was your vehicle moving? Did you try to increase the simulation step time, or substeps, to see if you are missing collision detection? The bvhTriangleMesh is one of the most demanding shapes, performance wise. Maybe you could try a convex hull and see if it changes the response. At least th...
by SynapticBytes
Fri Feb 15, 2013 5:35 am
Forum: General Bullet Physics Support and Feedback
Topic: Does softbody friction work
Replies: 2
Views: 2183

Does softbody friction work

I'm still struglling with drift when softbodies ashould ahve come to rest. I can almost remove it with a lot of parameter tweaking, but different shapes need vastly different tweaks, I'm thinking it's maybe just that friction isn't being applies. I've tried searching for kDF parameter references, an...