Maya - Trouble with Mental Ray and texture alpha

Vaztor

Hey guys

So I'm trying to make fur via a texture with an alpha and render with mental ray. However, I keep getting a filled in color where the alpha should be.



The color of the fill appears to be based on the color of the background object, so I'm guessing it's a photon or reflection issue but I'm not entirely sure how to handle it.

I've tried "Use Maya-style alpha detection on file textures"
and "Alpha is Luminance" to no avail.

Do you guys have any ideas?

Bartalon

Would your material happen to have a specular color channel?

Vaztor

The material is just a regular lambert shader so not that I know of

Luka

is your alpha fully transparent there? i know its obvious but i saw it happen many times before.

Illusions

Headed to work soon, so I don't have the time to do a full check, but does the texture file have an alpha channel, or was it just created with a transparent background? If it just has a transparent background, and no alpha channel, try creating an alpha channel to see if that fixes the issue. You may have to additionally play around with the transparency in the file or node linking in Maya to fix how the color will look with both transparency and alpha applied.

Vaztor

Luka wrote: »

is your alpha fully transparent there? i know its obvious but i saw it happen many times before.

I do believe so. It's just mapped to the file which has a transparent background and an alpha channel.

Illusions wrote: »

Headed to work soon, so I don't have the time to do a full check, but does the texture file have an alpha channel, or was it just created with a transparent background? If it just has a transparent background, and no alpha channel, try creating an alpha channel to see if that fixes the issue. You may have to additionally play around with the transparency in the file or node linking in Maya to fix how the color will look with both transparency and alpha applied.

It's possible I didn't implement the alpha channel properly. Right now the transparency on the lambert is only mapped to the main png file which was working for the software rendering I was doing earlier. I wasn't sure if I needed a dedicated alpha image or something more specific.

serriffe

Hi there Vaztor, I've had this problem before and I'm still looking for the solution for it. The problem only appears when you have all your photons setttings on- if you turn off all of your photon settings it should render the shadows from your alpha just fine. That's how far I've gotten on it so far-

Vaztor wrote: »

Hey guys

So I'm trying to make fur via a texture with an alpha and render with mental ray. However, I keep getting a filled in color where the alpha should be.



The color of the fill appears to be based on the color of the background object, so I'm guessing it's a photon or reflection issue but I'm not entirely sure how to handle it.

I've tried "Use Maya-style alpha detection on file textures"
and "Alpha is Luminance" to no avail.

Do you guys have any ideas?

MM

serriffe wrote: »

Hi there Vaztor, I've had this problem before and I'm still looking for the solution for it. The problem only appears when you have all your photons setttings on- if you turn off all of your photon settings it should render the shadows from your alpha just fine. That's how far I've gotten on it so far-

check box: "Direct Illumination Shadow Effects" in mental ray options, its under "indirect lighting-photon map"

last time i had a similar issue, that resolved the transparent shadow with GI and photons.

serriffe

MM wrote: »

check box: "Direct Illumination Shadow Effects" in mental ray options, its under "indirect lighting-photon map"

last time i had a similar issue, that resolved the transparent shadow with GI and photons.

Wow- man- that worked! how could've missed this option thanks MM, saved me tons of research time on this

Vaztor

Edit- Nevermind I got it working with mia materials and routing the file alpha into the cutout.

I'm still new to mental ray materials so I guess I better start getting my hands dirty with them lol