Search found 15 matches

by clanzotti
Mon Sep 03, 2007 1:51 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Impulse-based dynamic simulation library (IBDS)
Replies: 94
Views: 126402

Re: Impulse-based dynamic simulation library (IBDS)

Hi all, Does anyone tried to implement the method described in the paper? I've done a simple test using Scilab (A simple 1d chain) but i get strange bevahior. I've not digged too much into the details and maybe i'm doing something wrong. I found the paper interesting (even if some points are a littl...
by clanzotti
Fri May 18, 2007 9:07 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Cloth Bending Constraint
Replies: 4
Views: 10389

Re: Cloth Bending Constraint

Hi Erin, You may want to look at the Bridson's implementation: http://www-graphics.stanford.edu/~fedkiw/papers/stanford2003-06.pdf Regards, Carlo Lanzotti I would like to have a cloth bending constraint that can handle a non-zero rest angle. The constraint should not allow reflection of the vertices...
by clanzotti
Mon Mar 12, 2007 2:32 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Simple Physics Engine
Replies: 3
Views: 10026

I like the prices: 5000$ Half Commercial Use 20000$ Full Commercial Use Given the fact that it has less features than ODE or BULLET which are Open Source and free for commercial use and especially PhysX which has way more features and is free for the PC and PS3 I hardly see any value in this librar...
by clanzotti
Fri Mar 09, 2007 10:26 am
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Nice example of physic based gameplay
Replies: 8
Views: 17446

Ja, this game looks amazing... ...and even has an editor mode where you can build levels and share them (first video in the following link) http://www.gametrailers.com/gamepage.php?id=4491 The physics look great, but the gameplay and visual design make it just perfect. There also seems to be a lot ...
by clanzotti
Thu Feb 22, 2007 3:53 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Ageia paper on position based physics
Replies: 73
Views: 477387

Hi, ... Now I think it would be good to me to take a look at the methods used by Bridson (are they suitable for the realtime simulation?, any links are greatly appreciated :)) Definitely not, forgot about realtime simulation with complex piece of cloths/garments, especially with self collisions. Reg...
by clanzotti
Mon Jan 29, 2007 10:05 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Collision detection libraries
Replies: 11
Views: 16286

Re: Collision detection libraries

Hi, Hi, I am working on two things at the moment: 1. Implementing my impulse-based method on the GPU and 2. on deformable objects The simulation of joints on the GPU works already (a demo will soon be available on my homepage) but before the collision response can be implemented I need a collision d...
by clanzotti
Sat Jan 27, 2007 1:07 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Stan's cloth simulation demo/discussion
Replies: 30
Views: 61141

Re: bridson

Hi, Thank you for your detailed answer. Glad if i can be of help, i'm struggling with cloth simulation for years. The main problem for me with baraff's approach was, that you can easily end up having some frame with some penetration because the simulation fixes the penetration at the next timestep (...
by clanzotti
Fri Jan 26, 2007 1:53 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Stan's cloth simulation demo/discussion
Replies: 30
Views: 61141

Re: collision constraints

Hi Hello! I tried different ways to solve collisions. One way i followed was like this: 1. check for near faces and constrain (using z-vector like in the baraff paper) them not to move any further 2. simulateStep() 3. check for in-between collisions during position change x to x+1 4. if there where ...
by clanzotti
Sat Oct 07, 2006 9:56 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Ageia paper on position based physics
Replies: 73
Views: 477387

Hi John, [snip] Nice demos! Motion looks very good. Looking at the videos, it appears you are using somewhat complicated point mass networks for the rigid bodies. My system only uses 4 particles per RB (tetrahedrons), and uses the tetrahedral barycentric basis to provide realistic physical repositio...
by clanzotti
Sat Oct 07, 2006 1:29 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Ageia paper on position based physics
Replies: 73
Views: 477387

Hi Dirk, The equations of motion are (omitting @clanzotti Where did you use the methods before? Which projects did you work on? The examples look very nice - do you have any timing informations for the examples? Do they run in realtime? Cheers, -Dirk Yes, sorry for not included before such informati...
by clanzotti
Fri Oct 06, 2006 10:49 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Ageia paper on position based physics
Replies: 73
Views: 477387

Regarding section 7 of the paper, Future Work and rigid bodies: [snip] What I like about this method is it's based on constrained particle physics as opposed to optimization methods, which IMO looks much more realistic, and so far runs fast (have not spent any time optimizing the final system yet)....
by clanzotti
Fri Oct 06, 2006 10:34 am
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Ageia paper on position based physics
Replies: 73
Views: 477387

The two-way interaction stuff is nice. I have a problem with the treatment of collision constraints, though. Since you're moving the positions of the verticies around each iteration, the collision constraints that you detected outside of the constraint solver quickly become invalid. I believe you w...
by clanzotti
Wed Apr 05, 2006 9:51 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Which LCP's solver have been used by popular physics engine?
Replies: 24
Views: 49211

Conjugate gradient methods are typically used for solving implicit cloth systems. We had very little luck with that approach. Seems the CG solver would start diverging and give us large velocity spikes. CG is so often referred to as the best way to solve a PSD system, but in 16-bit floating point a...
by clanzotti
Thu Nov 17, 2005 1:32 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Physics of Plant
Replies: 4
Views: 9641

Hi, I've made a small mistake writing point to point constraint connecting branches and it caused constraints to oscillate ... at the moment whole simulation is stable even at 5 fps. I still didn't manage to implement rotational constraint blocking twists at the joint. I will try to research inform...
by clanzotti
Tue Nov 15, 2005 1:17 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Physics of Plant
Replies: 4
Views: 9641

Re: Physics of Plant

Hi, I'm trying to simulate a tree ;-) my first idea was to use spring/mass system to create soft body of the plant, problem with that approach was how to connect branches together without 1000's of springs Secound attempt was to build system from rigid bodies , costraints + springs to give elsticit...