Alpha Testing Question

Allright guys - Interesting problem hopefully someone can help me sort it out.

So i got this model (trying to simulate exhausts off the back of a ship), made the texture(s) (its a sprite) in particle illusion 3, spitting out a bunch of textures.

Here is the model looks in Maya. It is just a cylinder, with one side pinched in and the butt faces removed.

Heres how it looks whenever you are to the left or to the right of it ingame. Ideally how it should look

But when you go above/below of the thing(sort of extreme angle), it starts to alpha blend kind of funny.

I am not sure how to fix this, is it that the object is rendering in a funny order? because the sides and the middle part are separate objects, and the sides are the ones fussing with eachother. Are alpha tests done by polygon or by object?

Alpha sorting is by object.

These kinds of transparency issues come up pretty often. You should probably read the “How to control render order” page in the manual, which talks about this issue. There are also other posts in the forum by people with similar problems.

In this case, you want the exhaust flare to be drawn always following whatever it is it is occluding in your third picture there. You might be able to ensure this by setting an explicit sort order on your transparent items, for instance by putting one or more of them in the fixed bin. Another possibility would be to disable depth write on your exhaust flare, which would mean that when it does sort incorrectly, it will be a lot less obvious.


Drose, you rock! :slight_smile:

I turned off its depth write and fixed binned it before the other transparent stuffs, and it looks great!