I have a fantastic trick for cut trees

When tree is cut , you replace it by one in memory that is the same
but in two meshes cutted at middle.
-a upper tree with palms
-the base tree in the floor

If for example it have been cutted low :
you push the vertex of the cutted region of the base part to the low and you
push also the vertex of upper part to the same low position of cut.
After that just apply physic to the upper part to make it fall down
naturally


Don't know if someone understood, but i'm sure they use this
trick , no processor maths , only a good trick that can work very very well ,
as good as their MASSIVE LOD use and SPRITES