If the plane is aligned the sliding is quite simple, because I zero the component of the vector that matches the plane abs(normal). If the plane is not aligned I rotate the normal of the plane and the ''pushing'' vector to align the plane on xOy, I null the vector ''z'' component then I rotate them back. This seems to be a pretty time consuming opertion. I''m wondering if there is a simple firmula. Thanks MCO

Precalculating a vector for each triangle or plane which would be how much the object moves in some direction for each second, may help.

You can use that vector for many weights, too, because the relation is linear.

Hope it helps

Real programers are not afraid from maths!
(from an Asfixia Member I think)
JJpRiVaTe (Private Zone)