Search found 71 matches

by Ehsanizadi
Thu Jan 07, 2016 2:44 pm
Forum: General Bullet Physics Support and Feedback
Topic: Getting world coordinates of vertices of a convex hull body
Replies: 3
Views: 1484

Getting world coordinates of vertices of a convex hull body

Hi,

Does anyone know how to get coordinates of every vertices of a convexHull object?

I have a convex hull object in my scene, and I want to get the coordinates of its all vertices (x,y,z) in every time step.

Thanks
Ehsan
by Ehsanizadi
Fri Nov 13, 2015 1:45 pm
Forum: General Bullet Physics Support and Feedback
Topic: Internal force in a softbody
Replies: 4
Views: 1855

Re: Internal force in a softbody

I did not find any parameter regarding the internal force within softbody.cpp file. What is very strange to me is that why the amount of mass of soft body affect the behaviour of it and makes it stiffer?! In all of the formulations of the spring-mass systems (particle based systems for deformable ob...
by Ehsanizadi
Fri Oct 23, 2015 1:01 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: STL importer for softbodies
Replies: 0
Views: 2695

STL importer for softbodies

Hi, For a project I had to import a softbody from stl, I used the "loadFromMeshSTL.h" (in ../examples/Importers/ImportSTLDemo/), however I found that it only works for rigid bodies. Actually it gets each face and transfers the 3 vertexes individually to the vertices array. As a result, if you make a...
by Ehsanizadi
Mon Oct 05, 2015 1:16 pm
Forum: General Bullet Physics Support and Feedback
Topic: Internal force in a softbody
Replies: 4
Views: 1855

Re: Internal force in a softbody

still wondering ... :roll:
by Ehsanizadi
Wed Sep 30, 2015 8:29 am
Forum: General Bullet Physics Support and Feedback
Topic: Manual recovery from penetration problem
Replies: 5
Views: 2770

Re: Manual recovery from penetration problem

I think two parameters may affect this behaviour:

1) reducing the time increment
2) increasing the number of iterations of the solver (by default it is set to 20)

Let me know if this work or not.
by Ehsanizadi
Wed Sep 30, 2015 8:25 am
Forum: General Bullet Physics Support and Feedback
Topic: Internal force in a softbody
Replies: 4
Views: 1855

Re: Internal force in a softbody

Or where the principles and formulas of the softbody can be found?

For instance, how the bending constrains work, etc.
by Ehsanizadi
Mon Sep 28, 2015 9:56 am
Forum: General Bullet Physics Support and Feedback
Topic: Internal force in a softbody
Replies: 4
Views: 1855

Internal force in a softbody

Dear All, Does anyone know how to get the forces between to adjacent nodes in a softbody? I know that there is a linear stiffness in the softbody that acts as a spring stiffness, but multiplication of "change length" to that stiffness wont result in the internal forces. It seems that particle masses...
by Ehsanizadi
Thu Sep 24, 2015 2:06 pm
Forum: General Bullet Physics Support and Feedback
Topic: [SoftBody+SoftBody] Collisions [HELP!]
Replies: 1
Views: 1292

Re: [SoftBody+SoftBody] Collisions [HELP!]

I found it:
once you have set the settings as noted in "SoftDemo"
just add

Code: Select all

softBody->m_cfg.collisions		|=	btSoftBody::fCollision::VF_SS;
before adding the softbody to the world.

There is no need to register new collision algorithm.

Ehsan
by Ehsanizadi
Thu Sep 24, 2015 9:02 am
Forum: General Bullet Physics Support and Feedback
Topic: member variable of some classes
Replies: 5
Views: 3509

Re: member variable of some classes

I found a good reference for learning the physics of the softbodies.

In the chapter 8 (Particle systems) of the book "Physics-based animations" written by: Erleben/Sporring/Henriksen and Dohlmann, you cand find very useful info.
by Ehsanizadi
Mon Sep 21, 2015 12:39 pm
Forum: General Bullet Physics Support and Feedback
Topic: [SoftBody+SoftBody] Collisions [HELP!]
Replies: 1
Views: 1292

[SoftBody+SoftBody] Collisions [HELP!]

Hallo, Does anybody know how to set the collisionConfigurations in order to have all three: SoftBody + SoftBody collisions and RigidBody + RigidBody collisions and RigidBody + RigidBody collisions simultaneously? I took a look at the SoftDemo example code, Now I can set SoftBody + RigidBody collisio...
by Ehsanizadi
Mon Jul 27, 2015 10:20 am
Forum: General Bullet Physics Support and Feedback
Topic: Why my bullet simulation is not going on GPU?
Replies: 3
Views: 1596

Re: Why my bullet simulation is not going on GPU?

I'm still trying to figure out this, if somebody knows, I will be glad to hear hints. One thing is that when I run ./App_AllBu... and run "nvidia-smi" on another terminal, the usage of gpu is clear. But in my specific code (which takes long time to run, but I dont have any visualisation in that and ...
by Ehsanizadi
Thu Jul 09, 2015 1:47 pm
Forum: General Bullet Physics Support and Feedback
Topic: How can I increase the physical realism of my simulation?
Replies: 11
Views: 4120

Re: How can I increase the physical realism of my simulation

Although there is a slight difference in our methods, in your simulation, the system is highly dynamic and you get errors in positions, but in my case, the position is correct, however, the system is not that much dynamic (the rigid bodies are moving calmly), but the error in my simulation emerges i...
by Ehsanizadi
Thu Jul 09, 2015 8:35 am
Forum: General Bullet Physics Support and Feedback
Topic: How can I increase the physical realism of my simulation?
Replies: 11
Views: 4120

Re: How can I increase the physical realism of my simulation

Yes, I also posted here : http://www.bulletphysics.org/Bullet/php ... =9&t=10694

about the problem. when the time step decreases, the accuracy becomes better, but lower amounts beyond 0.001s, makes worse accuracy.
I am not sure if it is an issue or not.
by Ehsanizadi
Tue Jul 07, 2015 9:03 am
Forum: General Bullet Physics Support and Feedback
Topic: Accuracy of Bullet: number of iteration vs time step?
Replies: 0
Views: 2695

Accuracy of Bullet: number of iteration vs time step?

Hi, I'm working on simulation of particulate media when subjected to different stresses (normal and shear) using Bullet. Within the context of my work I have to also measure the accuracy of Bullet. My simulation involves about 2000 densely positioned spheres subjected to shear and normal stresses. I...