Search found 25 matches

by Oscar Civit Flores
Wed May 06, 2009 2:37 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: about CCD implementation and information
Replies: 2
Views: 1803

Re: about CCD implementation and information

Hi, You may also be interested in the work of Stephane Redon (and collaborators) on interval-arithmetic based continuous collision detection. Also, a google-search reveals this article about bullet's CCD approach with references (at the end) to the some relevant CCD research: http://www.continuousph...
by Oscar Civit Flores
Mon Mar 09, 2009 11:00 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Questions about hovering on a mesh
Replies: 2
Views: 1720

Re: Questions about hovering on a mesh

Definitely, manipulating object positions directly sounds dangerous. You can easily end up adding energy to the system and make thinks jitter or explode. From a theoretical prespective, what you are trying to do, if I understand it correctly, is adding an "ObjectOnSurface" constraint to all objects....
by Oscar Civit Flores
Mon Jul 28, 2008 2:29 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Physics APIs (C vs C++)
Replies: 5
Views: 4070

Re: Physics APIs (C vs C++)

Hi BGB, I agree with you on the benefits of having a decoupled API layer and an "internal" implementation of the physics engine. That simplifies a lot user-code, engine extensibility and parallelization, in my opinion. I am currently implementing not one but two engines concurrently (not in parallel...
by Oscar Civit Flores
Mon Jun 02, 2008 3:05 pm
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Detecting a particle "smashed" by polygons
Replies: 3
Views: 2740

Re: Detecting a particle "smashed" by polygons

Hi yfan, Handling multiple simultaneous collisions/contacts is never easy. If you're resolving collisions by projection in a Verlet+Relaxation way (based in Jakobsen's article maybe?) and you don't want to write a complex or expensive solution (like applying projections one by one and performing new...
by Oscar Civit Flores
Wed May 14, 2008 8:33 am
Forum: Research and development discussion about Collision Detection and Physics Simulation
Topic: Fish physics
Replies: 3
Views: 2643

Re: Fish physics

Some years ago I came across a paper by Demetri Terzopoulos that help you: http://portal.acm.org/citation.cfm?id=202162&dl=GUIDE&coll=GUIDE&CFID=27844896&CFTOKEN=39435710 However, I doesn't seem to be freely available on the web, so I'm afraid you'll need an ACM subscription to get it. Most universi...
by Oscar Civit Flores
Thu Aug 16, 2007 11:40 pm
Forum: Non-technical forum and license/patent discussion
Topic: Position Based Dynamics: Patent
Replies: 56
Views: 61028

For some reason it's usually impossible to read patent claims without falling asleep... I'm sure they do it on purpose. Anyhow, I understood the same you did (before falling asleep): An SPH API with asynchronous execution... what's new in that?

It's so sad...

Oscar
by Oscar Civit Flores
Sun Jul 22, 2007 8:35 pm
Forum: Non-technical forum and license/patent discussion
Topic: Position Based Dynamics: Patent
Replies: 56
Views: 61028

Yet another obvious patent

It seems that they've also invented asynchronous programming (tm)

http://www.freepatentsonline.com/20070038424.html

If you look at the example function calls you'll see some familiar Nx prefixes :twisted:

Oscar "Sue, me first!" Civit
by Oscar Civit Flores
Fri Jun 15, 2007 5:08 pm
Forum: Non-technical forum and license/patent discussion
Topic: Position Based Dynamics: Patent
Replies: 56
Views: 61028

For me patenting something which was, in fact, free knowledge, is stealing in a strict sense. So my stealing accusation is on the patent, not the paper, of course.

So let's blame the lawyers, they're used to it :)

Oscar
by Oscar Civit Flores
Fri Jun 15, 2007 3:31 pm
Forum: Non-technical forum and license/patent discussion
Topic: Position Based Dynamics: Patent
Replies: 56
Views: 61028

I can't agree... Understand me, I don't say the paper's bad or wrong, in fact, it's very clear and gives all information required to implement it, so in a tutorial sense, it's a very good paper, but the ideas are not new. Anyhow, good luck with all this and keep us informed (just in case somebody el...
by Oscar Civit Flores
Fri Jun 15, 2007 11:42 am
Forum: Non-technical forum and license/patent discussion
Topic: Position Based Dynamics: Patent
Replies: 56
Views: 61028

I'm just wondering if Jakobsen is aware of his algorithm being patented by others. Maybe someone could contact him... I mean, come on! The guy develops a super simple and fast algorithm, publishes it in gamasutra/GDC, and someone else comes and literally steals what he gave for free to everybody. So...
by Oscar Civit Flores
Thu Jun 14, 2007 10:51 pm
Forum: Non-technical forum and license/patent discussion
Topic: Position Based Dynamics: Patent
Replies: 56
Views: 61028

Hi all, This patent thing is looks like the arms race during the cold war to me... they've all gone MAD. http://en.wikipedia.org/wiki/Nuclear_arms_race That said, I don't think Müller or any other author of the paper is to blame, most of them have solid non-patented (AFAIK) research careers. Patenti...
by Oscar Civit Flores
Thu May 03, 2007 8:58 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Maya Nucleus
Replies: 7
Views: 7693

Hi, The attracting mesh in my system is a skinned mesh where each vertex attracts its corresponding particle with a user-defined coefficient [0,1] which I call "rigidity". In general I use it to control the global shape of a deformable surface/cloth or to avoid large deformations in specific areas. ...
by Oscar Civit Flores
Thu May 03, 2007 1:41 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Maya Nucleus
Replies: 7
Views: 7693

Interesting link, thanks! The method sounds very simple... but handling such dense meshes interactively must be a challenge, specially with continuous self-collisions. I'm curious abount how well particle-based fluids will perform, I've always thought eulerian fluids to be superior for CG purposes. ...
by Oscar Civit Flores
Mon Apr 16, 2007 5:52 pm
Forum: Links, Papers, Libraries, Demos, Movies, Comparisons
Topic: Maya Nucleus
Replies: 7
Views: 7693

Maya Nucleus

Hi All, I've recently found this in Autodesk's website: http://area.autodesk.com/custom/?id=4547 It's completely based on particles and claims to be able to simulate "any" kind of Model: rigids, cloth, fluids... Sounds like a "Theory Of Everything" for physics based animation. Just an excerpt: [quot...