[ODE] Problem with conveyor belts and static object (solved)

[Antonio Tejada Lacaci]

On Mon, 21 Apr 2003 14:31:16 -0500 (CDT), David Whittaker wrote:

Thanks David!

Setting mu to 1 did the trick (as I don't use dContactMu2, I don't
need to set mu2 at all), the higher value you set it to, the more
"slip-down" behaviour you get. Values of 10 were still causing the box
to slip under the static geometry.
What it normally happens, though, is that the box gets stuck in the
conveyor when it collides against the static object, which is fair
enough (if you stack enough heterogeneous objects in a row the first
object eventually begins to spin).

>Try setting mu to something other than dInfinity.  The "correct" solution
>would be a spinning around the static geom, but spinning requires both x
>and y components to the applied force, which is expressly forbidden by mu
>= infinity.  Adjust mu (probably in the 10-100 range), and it allows the
>box to slip in the x direction.  mu and mu2 should probably be the same if
>you want realistic behavior.  Also, don't forget that mu affects the
>interaction of the box with the static geom as well, but gets a somewhat
>random fdir1 perpindicular to the contact normal.  So it might turn out
>that it can only slip up and down the static geom with mu2 = 0, thus the
>sinking into the ground.  mu = mu2 would help here as well, turning the
>contact joint into a weak ball-and-socket joint of sorts.

>Hope that helps,
>David
>

>> When I drop a box, it begins to slide along the ground, which is OK, but
>> as soon as it collides against the static box, instead of
>> "torquing" left or right, it sinks, goes below and through the static
>> box and then it bounces up as if affected by bouyancy.
>>
>> You can see pictures of the problem at
>> http://www.telefonica.net/web/atejadalacaci/pfc/ode/index.html
>>

Cheers!

Antonio Tejada Lacaci