[ODE] Re: LCP

[Russ Smith]

Adam Moravanszky wrote:
> my dynamics sim uses a separate "custom" friction model for this
> reason. Thus, the friction forces are external forces as far as the
> LCP solver is concerned.

there are advantages to having friction forces as part of the LCP
model:
  * coulomb friction forces that are consistent per timestep (although
    approximations normally have to be made to get a solvable model).
  * multi-contact stick/slip transitions can be handled within a single
    timestep.
  * more stable force generation (i.e. friction forces are "the
    minimum needed" to maintain the friction model).
the big disadvantage is that is is slower.

> perhaps you would be interested to try my alternative.

so what exactly did you do? ODE needs a non-LCP friction model for
those people who need the extra speed and are willing to spend more
time tweaking for stability.

russ.


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