# Vray Render elements, Mtl\_select

**URL:** <https://forums.chaos.com/t/vray-render-elements-mtl-select/13519>\
**Category:** Issues\
**Created:** [February 1, 2007, 9:04am UTC](https://forums.chaos.com/t/vray-render-elements-mtl-select/13519 "2007-02-01T09:04:08Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Felix2](https://avatars.discourse-cdn.com/v4/letter/f/6f9a4e/32.png) [@Felix2](https://forums.chaos.com/u/Felix2)\
**Post date:** [February 1, 2007, 9:04am UTC](https://forums.chaos.com/t/vray-render-elements-mtl-select/13519/1 "2007-02-01T09:04:08Z")

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Hi,

It seems that vray\_mtlselect render pass isnt working right? I put vray material with dirt in diffuse slot into vray\_mtlselect parameters material slot and when I render I get black render with alpha in the alhpa channell? why I cant get dirt in there?

Another problem is that I cant drag any material from meditor to vraymtlselect material slot and neither viceverse. I think this is a bug?

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**Author:** ![vlado](https://avatars.discourse-cdn.com/v4/letter/v/779978/32.png) [@vlado](https://forums.chaos.com/u/vlado)\
**Post date:** [February 1, 2007, 9:18am UTC](https://forums.chaos.com/t/vray-render-elements-mtl-select/13519/2 "2007-02-01T09:18:41Z")

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You need to have the material applied to something in your scene. VRayMtlSelect only extracts this material from the image and puts it in its own layer.

Render elements in V-Ray can only extract information that is computed during the normal course of rendering calculations; they cannot show information that is not in the rendering.

Best regards,  
Vlado

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**Author:** ![Felix2](https://avatars.discourse-cdn.com/v4/letter/f/6f9a4e/32.png) [@Felix2](https://forums.chaos.com/u/Felix2)\
**Post date:** [February 1, 2007, 10:03am UTC](https://forums.chaos.com/t/vray-render-elements-mtl-select/13519/3 "2007-02-01T10:03:21Z")

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I see. now its works fine. drag drop bug is not the big problem sience u can select the materials from meditor dialog

anyways. I was looking for extra pass for ambient which I made with dirtmap. but if I need to add this dirtmap to all scene objects then I can use mtl override and just output the ambient pass.

What is the use of mtlselect? what is the difference of mtl override and mtlselect then?

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**Author:** ![instinct](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/instinct/32/74489_2.png) [@instinct](https://forums.chaos.com/u/instinct)\
**Post date:** [February 1, 2007, 10:24am UTC](https://forums.chaos.com/t/vray-render-elements-mtl-select/13519/4 "2007-02-01T10:24:15Z")

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I think you misunderstood the purpose of Mtl\_Select. It is not meant as an alternate Material Element, but it is meant to isolate a specific material in a seperate renderelement. That way you can render out an extra element that contains only the objects that have the materials applied.

Regards,  
Thorsten

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**Author:** ![Felix2](https://avatars.discourse-cdn.com/v4/letter/f/6f9a4e/32.png) [@Felix2](https://forums.chaos.com/u/Felix2)\
**Post date:** [February 1, 2007, 12:10pm UTC](https://forums.chaos.com/t/vray-render-elements-mtl-select/13519/5 "2007-02-01T12:10:05Z")

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yea. I was just looking something handy 🙂 now this is very clear.

thanks! 😛