Comments for generalrelativity http://blog.generalrelativity.org Game-Oriented Development Sun, 01 Aug 2010 05:54:40 +0000 http://wordpress.org/?v=2.6.5 Comment on Constrained Dynamics 2: Joints and Global Constraints by drew http://blog.generalrelativity.org/actionscript-30/constrained-dynamics-2-joints-and-global-constraints/#comment-156242 drew Wed, 28 Jul 2010 13:47:58 +0000 http://blog.generalrelativity.org/?p=219#comment-156242 <a href="#comment-156220" rel="nofollow">@Philip</a> If you have zeroes on the diagonal, you're doing something incorrectly. Shoot me an email (drew at generalrelativity dot org) with the constraint equation and code and we'll figure out what's going on. @Philip
If you have zeroes on the diagonal, you’re doing something incorrectly. Shoot me an email (drew at generalrelativity dot org) with the constraint equation and code and we’ll figure out what’s going on.

]]> Comment on Constrained Dynamics 2: Joints and Global Constraints by Philip http://blog.generalrelativity.org/actionscript-30/constrained-dynamics-2-joints-and-global-constraints/#comment-156220 Philip Wed, 28 Jul 2010 06:45:57 +0000 http://blog.generalrelativity.org/?p=219#comment-156220 Sorry to bother you again, the reason I asked you about the method you use to solve linear system is because when I tried to implement constraints I found myself with a system matrix with some zeros on the diagonal and, given I use Gauss-Jordan to solve it, the solution goes to infinity. Maybe I missed something in your article, but if I have 2 independent bodies and I try to apply a constraint to the second one (b2.index > b1.index): I have JWJt matrix that has 3 zeros on the first 3 diagonal values and then the body 2 constraint gradients (if I'm not wrong). Any help? Thank you. Sorry to bother you again,

the reason I asked you about the method you use to solve linear system is because when I tried to implement constraints I found myself with a system matrix with some zeros on the diagonal and, given I use Gauss-Jordan to solve it, the solution goes to infinity.
Maybe I missed something in your article, but if I have 2 independent bodies and I try to apply a constraint to the second one (b2.index > b1.index): I have JWJt matrix that has 3 zeros on the first 3 diagonal values and then the body 2 constraint gradients (if I’m not wrong).

Any help? Thank you.

]]> Comment on Constrained Dynamics 2: Joints and Global Constraints by drew http://blog.generalrelativity.org/actionscript-30/constrained-dynamics-2-joints-and-global-constraints/#comment-156076 drew Mon, 26 Jul 2010 04:33:13 +0000 http://blog.generalrelativity.org/?p=219#comment-156076 Thanks for the links, David. Thanks for the links, David.

]]> Comment on Constrained Dynamics 2: Joints and Global Constraints by drew http://blog.generalrelativity.org/actionscript-30/constrained-dynamics-2-joints-and-global-constraints/#comment-156075 drew Mon, 26 Jul 2010 04:14:49 +0000 http://blog.generalrelativity.org/?p=219#comment-156075 <blockquote cite="#commentbody-156024"> <strong><a href="#comment-156024" rel="nofollow">Philip</a> :</strong> <p>What method do you use to solve the linear system?</p> </blockquote> I use LU decomposition.

Philip :

What method do you use to solve the linear system?

I use LU decomposition.

]]> Comment on Constrained Dynamics 2: Joints and Global Constraints by Philip http://blog.generalrelativity.org/actionscript-30/constrained-dynamics-2-joints-and-global-constraints/#comment-156024 Philip Sun, 25 Jul 2010 10:38:08 +0000 http://blog.generalrelativity.org/?p=219#comment-156024 Great article. What method do you use to solve the linear system? Great article.
What method do you use to solve the linear system?

]]> Comment on Constrained Dynamics 2: Joints and Global Constraints by David http://blog.generalrelativity.org/actionscript-30/constrained-dynamics-2-joints-and-global-constraints/#comment-156012 David Sun, 25 Jul 2010 08:06:13 +0000 http://blog.generalrelativity.org/?p=219#comment-156012 <a href="#comment-154291" rel="nofollow">@drew</a> A couple days ago I noticed that the Bullet Physics Library website has a mirror of Erin's paper and the accompanying slides from a GDC presentation. I figured I'd post the links here in case anyone is interested. Paper: http://www.bulletphysics.com/ftp/pub/test/index.php?dir=physics/papers/&file=IterativeDynamics.pdf Slides: http://www.bulletphysics.com/ftp/pub/test/index.php?dir=physics/papers/&file=IterativeDynamicsSlides.pdf The Bullet site mirrors quite a few other papers as well. You can find them all at http://www.bulletphysics.com/ftp/pub/test/index.php?dir=physics/papers/ @drew
A couple days ago I noticed that the Bullet Physics Library website has a mirror of Erin’s paper and the accompanying slides from a GDC presentation. I figured I’d post the links here in case anyone is interested.

Paper: http://www.bulletphysics.com/ftp/pub/test/index.php?dir=physics/papers/&file=IterativeDynamics.pdf
Slides: http://www.bulletphysics.com/ftp/pub/test/index.php?dir=physics/papers/&file=IterativeDynamicsSlides.pdf

The Bullet site mirrors quite a few other papers as well. You can find them all at http://www.bulletphysics.com/ftp/pub/test/index.php?dir=physics/papers/

]]> Comment on Grape Animation Library by John de Beer http://blog.generalrelativity.org/actionscript-30/grape-animation-library/#comment-155952 John de Beer Sat, 24 Jul 2010 09:44:04 +0000 http://blog.generalrelativity.org/?p=143#comment-155952 Hi Drew, thanks for replying! I succeeded to rebuild the second example. After my holiday I am going to try to replicate the first example. This one is particularly interesting, because I want to use the tweening technique for making math tutorials for my students to demonstrate some algebra (substitution, simplifying equations etc.). I hope there is also an opportunity to tween the transparency along the path. There is a great potential for this tween class. Thanks for making this public. Hi Drew, thanks for replying! I succeeded to rebuild the second example. After my holiday I am going to try to replicate the first example. This one is particularly interesting, because I want to use the tweening technique for making math tutorials for my students to demonstrate some algebra (substitution, simplifying equations etc.). I hope there is also an opportunity to tween the transparency along the path.
There is a great potential for this tween class. Thanks for making this public.

]]> Comment on Grape Animation Library by drew http://blog.generalrelativity.org/actionscript-30/grape-animation-library/#comment-155807 drew Thu, 22 Jul 2010 02:33:05 +0000 http://blog.generalrelativity.org/?p=143#comment-155807 <a href="#comment-155364" rel="nofollow">@John de Beer</a> Hey John, what isn't working for you? I use Flash Builder to develop, so I don't end up with any .fla's, but if you post your code/files we can figure out what's going wrong. Also, feel free to email me. @John de Beer
Hey John, what isn’t working for you? I use Flash Builder to develop, so I don’t end up with any .fla’s, but if you post your code/files we can figure out what’s going wrong. Also, feel free to email me.

]]> Comment on Grape Animation Library by John de Beer http://blog.generalrelativity.org/actionscript-30/grape-animation-library/#comment-155488 John de Beer Sat, 17 Jul 2010 11:58:53 +0000 http://blog.generalrelativity.org/?p=143#comment-155488 <a href="#comment-155484" rel="nofollow">@John de Beer</a> Sorry, did not press F5 and thought my message was not posted. @John de Beer
Sorry, did not press F5 and thought my message was not posted.

]]> Comment on Grape Animation Library by John de Beer http://blog.generalrelativity.org/actionscript-30/grape-animation-library/#comment-155484 John de Beer Sat, 17 Jul 2010 10:17:26 +0000 http://blog.generalrelativity.org/?p=143#comment-155484 Drew, can you post some fla's for the above swf files? For some reason I can not make it work. Drew, can you post some fla’s for the above swf files? For some reason I can not make it work.

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