This is the first time I use the physic engine (commercial = 1 object). The goal is that the player cuts a tree, and then the physic engine let the tree fall to the ground. The ground itself is a model, too.

The cutting itself is not the problem. It works fine. After cutting, the tree morphs to a stump and the stump creates the cuttet tree above it. So we have two objects, the stump and the cuttet tree. Now the physic engine takes control over the cutted tree part.
Code:
var[3] erdanziehung = 0, 0, -368;
function cutted_tree()
{
my.polygon = on;
phent_settype(my, ph_rigid, ph_poly);
phent_setmass(my, 10, ph_poly);
phent_setdamping(my, 0, 0);
phent_setgroup(my, 1);
ph_setgravity(erdanziehung);
ph_selectgroup(1);
}
The problem I have is that the physicobject jumps wild through the area and then dissapears. It is not really gone, but I don't know where it is. I have set the mass to more and to less than 10, and I already modified the gravity to more and less than -368. These actions didn't solve the problem.
Any suggestions?