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someloudnoise 11 posts
smart minds,
back again with a technical vray/max9 question for yah':
I have a texture baked scene with mirrors, and as we all know reflections are view dependent, so the mirrors don't render their reflections properly in a texture baked scene. I am trying to render the mirrors in a seperate pass, a "reflections pass" if you will (brute force method). However, I need to isolate all the reflective objects while keeping their reflections accurate, so I can't just turn all the other non-reflective objects invisible or non-renderable. I think I can do this by assigning them an object ID or a gBuffer ID or something with a certain value and then rendering only those objects with that ID. Then composite that rendering ontop of the texture baked renderings. Emphasis on "I think I can..."
Is this possible? How would I do this in Vray?
Praise and respect to those with the answers.
- someloudnoise
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someloudnoise 11 posts
i might of figured out my own answer using a totally different method (not using object ID or gBuffer ID). check this and let me know if theres any problems with what I'm doing:
select the objects you want to "not-render", right-click > Vray object properties > matte properties > change Alpha contribution to -1.0.
The objects should still render in reflections, refractions, cast shadows on surrounding objects, etc... but render with a solid black alpha. I haven't tested foreground masking yet, if that makes sense. will do that soon. need to test reflections, refractions, etc... but so far so good, no problems ran into yet.
and i dont have to do any messy compositing tricks later, as the alpha is built right into the rendering. just drop and go.
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someloudnoise 11 posts
just tested out foreground masking, and it works great. to explain:
if you have a sphere in the foreground of your scene and a mirror in the background of the scene, normally the mirror would reflect the sphere and both would be present as white objects in the alpha channel. if you select the foreground sphere and change it's vray object properties to -1.0 alpha contribution, then the mirror in the background will still reflect the sphere, but the sphere will appear as a solid black object in the alpha channel. the mirror will still appear white in the alpha.
i bet a ton of people already know this, sorry if it's an old hat technique.
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diemacht 1,045 posts
You could make it non renderable but still seeable in reflection in the properties menu of the object.
I used it on my last project and it worked very well with Final Render. the non renderable objects were still in reflections and diddnt affect the alpha.
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someloudnoise 11 posts
i need the non-renderable objects to affect the alpha. this is achieved in vray by setting the alpha properties.
i thought about my situation more and realized that i could use a flat mirror material in the diffuse slot in the texture baked scene to make the mirrors accurately reflect. no big complicated solution, just simplicity.
