[ODE] test problems?

[Russ Smith]

Ivo Kwee wrote:
> We are in the moment to choose a physics engine for a robotics
> project. Currently we are looking into MathEngine, DynaMechs,
> Darwin2K, ODE and Havok.
>
> Can anyone suggest a set of "hard" test problems to implement in
> order to compare these packages? tests for speed, accuracy,
> stability, scaling up.

you could try:
* measure the step speed for N body chain and N body tree. DynaMechs is
  O(N), the rest are O(N^3) (except i don't know about Darwin2K).
* implement highly contacting systems and see how they behave.
  an example is baraff's part feeder (i'm not sure which paper i saw
  this in).
* implement stiff systems, to test the integrator. examples are systems
  with strong springs or lots of damping.

note that comparing packages is much more meaningful when it is done
on real problems, not toy or acedemic problems. so i would recommend
that you try to build a (very) simple version of your project in
each package. also note that Mathengine and ODE are roughly the same
feature-wise, except that Mathengine has more collision primitives,
more joints, and costs more.

would you be able to report your results (or a link to them) to this
mailing list? i would love to know which areas ODE is deficient in.

russ.

--
Russell Smith
http://www.q12.org