I have thousand of trees on Max that are already pivot point centered, but i believe the pivot point must be bottom centered to billboard work right? How can i do this? There are thousand objects. Thanks.
No, you just set that in the exporter, it'll use the bottom of the faces. If you have the triangulation correct. If not, you're most likely screwed. The triangulation needs to be top left to bottom right.
Ya, make sure you set the bottom. And set the vertex alpha to 0.9999, and then change the vertex colour to something other than white, then change it back to white, sometimes the alpha doesn't take until you reset the colour.