Maya transparency rendering issues

John Warner · May 2009

hey guys, i've got some decals that i'm trying to render in a scene in maya. basically i've got cards that have transparent alpha setups going on.

everything looks fine in the viewport, but when i do a render in maya, I'm getting the transparent bits of the card showing up very subtlly.. as if they're mostly transparent but just slightly vissible. this shit also casts shaddows.

It's really fucking me, i gotta tell you.

anyone have any ideas?

ChaosEidolon · May 2009

Are you using the Maya renderer or a plugin program?

I am no pro at renders, but I do know that Maya is...well...a steaming PoS when it comes to dealing with transparency and sorting. This goes for viewport but I think it carries over to it's default renderer as well.

Not very helpful im afraid, but if you have access to another software package id recommend giving it a go in that instead.

Microneezia · May 2009

check your spec maps! that always gets me, on the alpha sections make sure no spec is on that area!

MoP · May 2009

Yes indeed, it's the same in any renderer - you have to mask out any other maps you're using with the same opacity mask, since the specular level (or reflection, or whatever similar maps you're using) on those parts might still have some value, unless you already filled those areas completely black in your textures.

Mark Dygert · May 2009

Can't you disable shadow cast/receive on a per object basis? Turning both off for the cards might help.

rooster · May 2009

also if you're raytracing shadows (and you want an alphad object to cast just the shadow of your alpha) go into material attributes>raytrace options and turn shadow attenuation to 0. that should remove any ghost shadows of polygons and leave the shadow from just the shape.

if that doesnt work try turning the attenuation to 1.. im pretty sure its 0 though :P

John Warner · May 2009

gah sorry for the late replies guys. I'm an asshole.

It's not a specular issue- the material has no spec. in fact, it's a goddamn lambert. the effect that i'm getting is making it look as if the transparent areas of my texture are actually not completely transparent... as if the value i have in the alpha there is like 10,10,10 or something.

it's bullshit.

I AM using raycast shadows.

Vig, I'll play with that and see if i can't figure something out.

Rooster- that sounds like it might jolly well work. I'm gonna give it a shot.

Harryscary276 · May 2009

Well one thing you can do in Maya is go into Light linking, this is one of those times when you want to make sure everything is named because of the list and how light linking works, basically find the card shape on the list and turn off the particular light for that particular shape, so the light will have no affect on it as if it is not there

as for the transparent map, cant offer anything that hasn't already been said

GL

Toast · May 2009

roosters right sounds like shadow attenuation issue.

ChaosEidolon wrote: »

I am no pro at renders, but I do know that Maya is...well...a steaming PoS when it comes to dealing with transparency and sorting. This goes for viewport

Mayas fine on qualified hardware. not gaming cards. cant drive a 911 nicely with cheap wheels.

Maya transparency rendering issues

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