Alphas + doublesided polys

ckaos

Hi all!
I'm having a bit of problems with alphas : i'm currently preparing my mesh in wings 3d and noticed that all the "planes" that i put in place in order to recieve the alphas are actually to polys "glued" to each other: i wonder if this is ok or if an alpha plane should actually be only one poly only .
Thanks in advance!

rooster

that probably depends on what engine you're preparing it for, but I believe it should be alright. I recently used double sided polies for transparent fish fins, although the verts of the two planes were un-welded. It worked fine in renderware, and we're using an older version, so I imagine a more modern engine could handle it. Easiest thing to do is try it and see how it turns out.

Michael Knubben

ckaos: if you apply the blue "hole" material, upon export that face will be deleted.
So just give one out of two faces that material, and it'll be good.
It's just that wings needs its meshes to be one solid mesh, without holes.

ckaos

Thanks for the quick answers guys !
*Rooster : well it's for no specific engine but it works fine indeed with a litlle uvmanipulation! thanks!
*Mightypea : wow that's something i have wondered about for ages, thanks , you just saved me a few hundred polies ! thanks !

Joshua Stubbles

If you actually have two physical polys on top of each other like that, you'll get a lot of z-buffer artifacts on PS2 and Xbox. I think you'd be better off using a single poly, with the 2-sided material checked. If you're not doing console stuff, it doesn't really matter then

KDR_11k

You mean because consoles have no backface culling?

Steve Schulze

Ps2 and PSP don't... I was under the impression that XBox did.

KDR_11k

Strange, I thought BFC improved performance.

Manic

same here.

Joshua Stubbles

Xbox does, yea.
BFC does improve rendering time, but the PS2/PSP are rather weak in comparison to Xbox and PC, obviously. The amount of processing time it takes to remove the backfaces on PS2/PSP would negate any benefit you get from the faster rendering.