Search found 19 matches
- Mon Mar 21, 2011 9:52 pm
- Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
- Topic: Parallelizable conjugate gradient-based MLCP solver
- Replies: 6
- Views: 16149
Re: Parallelizable conjugate gradient-based MLCP solver
Thanks for sharing. That is really grand of you! I will read it. First reflection. I don't see any system with complementarity conditions among the test systems. What type of systems that imposes bounds on the multipliers or velocity have you considered? And are the results for that also just as pos...
- Mon Jan 03, 2011 7:03 am
- Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
- Topic: Hybrid Multiresolution Wire
- Replies: 0
- Views: 6461
Hybrid Multiresolution Wire
We describe a method for the visual interactive simulation of wires contacting with rigid multibodies. The physical model used is a hybrid combining lumped elements and massless quasistatic representations. The latter is based on a kinematic constraint preserving the total length of the wire along a...
- Mon Jan 03, 2011 7:02 am
- Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
- Topic: Constraint Fluids
- Replies: 0
- Views: 5767
Constraint Fluids
We present a fluid simulation method based on Smoothed Particle Hydrodynamics (SPH) in which incompressibility and boundary conditions are enforced using holonomic kinematic constraints on the density. This formulation enables systematic multiphysics integration in which interactions are modeled via...
- Mon Dec 27, 2010 8:36 pm
- Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
- Topic: Release of AGX, and some new videos and stuff from Algoryx
- Replies: 4
- Views: 12850
Re: Release of AGX, and some new videos and stuff from Algor
You can find pre-prints here Constraint fluid: http://www.physics.umu.se/english/research/statistical-physics-and-networks/complex-mechanical-systems/fluids-and-solids/ Realtime hybrid wire: http://www.physics.umu.se/english/research/statistical-physics-and-networks/complex-mechanical-systems/realti...
- Wed Aug 11, 2010 8:24 am
- Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
- Topic: New research on real-time deformable body dynamics (FEM).
- Replies: 28
- Views: 70944
Re: New research on real-time deformable body dynamics (FEM)
Nisse and XperienS: I only know to use CG to solve linear eqaution but don't know how to use it solve LCP, Could you refer me some Material how to use active set in CG method to solve LCP with unilateral contacts and box constraint like friction? I guess we are all looking for ways to do that. The ...
- Mon Aug 09, 2010 8:29 am
- Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
- Topic: New research on real-time deformable body dynamics (FEM).
- Replies: 28
- Views: 70944
Re: New research on real-time deformable body dynamics (FEM)
Impressive work! Are you solving the contacts as unilateral contacts - with friction - using the CG solver as well? Do you have your own method for handling the active set in the LCP solve or do you use some standard method? That is the hardest part to parallelize as I understand the problem. Keep u...
- Mon Apr 05, 2010 5:24 pm
- Forum: Career Opportunities
- Topic: PhD Student Position
- Replies: 0
- Views: 39572
PhD Student Position
PhD Student Position in Computational Science and Engineering - Umeå University, Sweden. We are looking for an exceptional PhD student to join our interdisciplinary group focusing on modeling and numerical simulation of complex mechanical systems. This is a full-time position over a period of four y...
- Sat Mar 20, 2010 7:24 am
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Non elastic rope II
- Replies: 4
- Views: 10004
Re: Non elastic rope II
This is a well-known instability. Light elements under high tension vibrates at high frequency - like tuning a guitar string. When the vibrational frequency becomes close to or smaller than the time-step size these high-frequency modes may develop into instabilities. Increasing mass, element size an...
- Mon Mar 01, 2010 7:41 pm
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Solids collision response theories [?]
- Replies: 2
- Views: 3832
Re: Solids collision response theories [?]
I recommend the book "Computational Granular Dynamics" by Pöschel and Schwager. As the titel reveals it is oriented towards compuational techniques and simulation and covers both explicit force methods (penalty methods based on physical deformation models - eg the Hertz model), impulse eve...
- Fri Nov 20, 2009 7:26 am
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Wake and sleep strategies
- Replies: 5
- Views: 5383
Re: Wake and sleep strategies
dellsmaith
You are kidding with me, right!? In that case I find it actually hilarious The relaxation process is indeed good for wake and sleep, especially for large mammals.
But if whas a serious tip, please provide me with the precise keywords...
You are kidding with me, right!? In that case I find it actually hilarious The relaxation process is indeed good for wake and sleep, especially for large mammals.
But if whas a serious tip, please provide me with the precise keywords...
- Thu Sep 24, 2009 11:48 am
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Finite Elements Method: are there proble,s with stability?
- Replies: 57
- Views: 79089
Re: Finite Elements Method: are there proble,s with stability?
FD, Have you (or anyone else) tried preconditioning of the iterative solver? That is, you warm-start the solver with lagrange multipliers that is the best estimation of the solution you can do a priori - instead of using the initial iteration solve. The estimation could be a direct solve of a subsys...
- Thu Sep 24, 2009 8:23 am
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Finite Elements Method: are there proble,s with stability?
- Replies: 57
- Views: 79089
Re: Finite Elements Method: are there proble,s with stability?
The "How to make new joints in ODE" http://ode.org/joints.pdf has some even more details on this as well. One thing that is not stressed enough in that text, I think, is that for the mapping of the spring stiffness and damping coefficients to CMF and ERP to hold relies critically on that t...
- Tue Sep 15, 2009 9:49 am
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Finite Elements Method: are there proble,s with stability?
- Replies: 57
- Views: 79089
Re: Finite Elements Method: are there proble,s with stability?
...it makes the constraints soft and in my opinion this is not what people want (e.g. stretchy ragdolls).-Dirk Well, ideal is to be able to parametrize the joint stiffnes ranging from soft to indefinetly stiff AND use conventional material parameters for this (e.g. Young's modulus etc). In this thr...
- Sun Sep 13, 2009 11:31 pm
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Finite Elements Method: are there proble,s with stability?
- Replies: 57
- Views: 79089
Re: Finite Elements Method: are there proble,s with stability?
It seems the use of iterative v.s. direct solver might explain the difference in stability. But I am not sure. I use iterative solver sometimes as well and don't recall any particular difficulties with stability in the stiff limit. The problem usually shows up as the material being overly elastic wh...
- Sun Sep 13, 2009 8:44 am
- Forum: Research and development discussion about Collision Detection and Physics Simulation
- Topic: Finite Elements Method: are there proble,s with stability?
- Replies: 57
- Views: 79089
Re: Finite Elements Method: are there proble,s with stability?
This paper has a few details on how DMM works, it might be worth checking out: http://www.cs.berkeley.edu/b-cam/Papers/Parker-2009-RTD/ Indeed, this is very good work. Very nice to see to see it working in a commercial game and that the physics is essential for the game play as well. I am intereste...