Help please: I'm doing a Christmas tree, the branches have an alpha channel.
when I see it in the program, if you rotate 180 degrees, the branches were
ahead, keep looking forward, as if transparency to all and looks ugly.
Command an example for you to see what I mean, http://www.box.com/s/pr5qy6t56qadjxk4pfhg
you look in the MED "engine preview" and you turn it 180 degrees,
Forgive my bad English.

That's a problem with transparent textures/ objects, you will need an alpha test material:
http://www.opserver.de/wiki/index.php/ImprovedOverlay