Render Reflections and Shadows Passes to EXR

[ITdreamer]

Hello, friends.

How can I render Shadows pass and Reflections pass to layers in one EXR file. Rendering using Mantra.

I know that I need to add Extra Image Plane, and I did that with Normals pass. But normals pass was in presets. There is no shadows and reflections pass in presets, so, please help me to render these passes. What I need to do to render them?

Thanks a lot.

[symek]

Hello, friends.

How can I render Shadows pass and Reflections pass to layers in one EXR file. Rendering using Mantra.

I know that I need to add Extra Image Plane, and I did that with Normals pass. But normals pass was in presets. There is no shadows and reflections pass in presets, so, please help me to render these passes. What I need to do to render them?

Thanks a lot.

You probably come from another package where shaders are already bundled in a system with multiply predefined variables to export as passes. Mantra is a programmable rendering engine, which means that you have complete freedom what, when, and where to export as variables from shading context. Price for that is a little setup need to be done before using this freedom.

Take a look on materials from Gallery. Step inside them and check VEX builder network for surface shader. A couple of green nodes at the end of network are export variables/passes you can use in Mantra ROP.

What is happening there is that shader creator decides what will be needed and creates additional export variables (besides of existing Cf, Of, Af, Depth, Normals) by adding parameters with export toggle turned on. This technique is better known as AOV in PRMan (Arbitrary Ouput Variables).

After that or similar setup (you can write or wire your own shaders this way of course), you simply add variables name with proper type in Mantra ROP and a dreams come true! They cannot exist there as presets because you're the only person who knows what you wanted to export .

Most of materials Houdini comes with have predefined set of AOV for you. Their names are just a convention: specularExport, paintExport, diffuseExport, reflExport etc etc.

Shadows are little different topic since I think much easier way for doing this (without modifying shaders for surface, light and shadows) is to simply render this pass separately with VEX Shadow Matte shader applied to your surfaces.

cheers,

sy.

PS Check also here on odforce Peter's example of exporting variables per single light. This is awesome!

http://forums.odforce.net/index.php?showtopic=6969

Edited July 13, 2008 by SYmek

[ITdreamer]

Thank you very much.

I really came from another package. It was Maya )).

I am not afraid of programkming. I just needed to know from where to start.

Thanks again.