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View Full Version : maya2009 renderpass haven't an alpha??


hcmstory
11-01-2009, 07:40 AM
I using maya2009 with mental ray render and I set the several render passes such as diffuse,

and specular. But the passes are not have alpha channels after I batch render. Only

beauty pass have an alpha..How can I solve it..?

AlexTNT
11-01-2009, 09:44 AM
Under redering settings

Quality->Framebuffer change Data Type to RGBA (byte) 4x8 bit

see if this works

coccosoids
11-01-2009, 10:26 AM
Under redering settings

Quality->Framebuffer change Data Type to RGBA (byte) 4x8 bit

see if this works

I think he means that passes like diffuse, reflection and so on do not have an alpha component, which... i dunno, are they suppose to?! :curious:

JasonA
11-01-2009, 03:05 PM
normally, I dont use alphas on every render pass. I use the masterbeauty's alpha at the end of my comp (assumining its what i need, else i make my own out of an RGB matte) and punch 1 alpha through all the layers.

However if you really want it, I think you can override the frambuffer in each render pass global, by increasing the channels from 3 to 4 (RGBA). In doing this you run the risk of developing matte lines from all your passes' alpha's not being exactly the same.

hcmstory
11-01-2009, 03:08 PM
I think he means that passes like diffuse, reflection and so on do not have an alpha component, which... i dunno, are they suppose to?! :curious:


Yes. you are right. That's are what I mean.

I want to know that how can I get alpha channels on(from?) each render passses like as

diffuse, reflect, specular and so on. They haven't alpha channels. Only MasterBeauty have

an alpha channel.

hcmstory
11-01-2009, 03:49 PM
normally, I dont use alphas on every render pass. I use the masterbeauty's alpha at the end of my comp (assumining its what i need, else i make my own out of an RGB matte) and punch 1 alpha through all the layers.

However if you really want it, I think you can override the frambuffer in each render pass global, by increasing the channels from 3 to 4 (RGBA). In doing this you run the risk of developing matte lines from all your passes' alpha's not being exactly the same.


Thanks for your answer :D Your answer was very helpful~

Your method by using masterbeauty's alpha is good. but if we set an alpha on the

render pass global, it can be more good method I think. The reason is that it has an

edge on the outline too, but it can settlel by using just check(or choose)premultiply

on the composite programs(like a nuke or shake) How do you think about?

sorry I'm not good at English

JasonA
11-02-2009, 03:31 PM
In my experience, it usually creates more problems, which is why I avoid working that way. As for it being a 'natural' look... well honestly i don't think this is an issue. An alpha is an alpha.. If you only use one, less chances of matte lines from the passes...

I composite my render passes in Nuke, and when I render my footage from maya I render with the alpha unpremultiplied. My framebuffer settings are for RGBA (for master beauty) and all my render passes are set to RGB.

hcmstory
11-03-2009, 02:29 AM
In my experience, it usually creates more problems, which is why I avoid working that way. As for it being a 'natural' look... well honestly i don't think this is an issue. An alpha is an alpha.. If you only use one, less chances of matte lines from the passes...

I composite my render passes in Nuke, and when I render my footage from maya I render with the alpha unpremultiplied. My framebuffer settings are for RGBA (for master beauty) and all my render passes are set to RGB.

Yea, Thank you very much~ I hope you always enjoy your work and stay healthy :D

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