Hi! I am a CG student learning renderman and Houdini by myself.
I have 2 objects in geo level. One of the objects is atttached by a “shader” node. The other object is attached by a “Rman shader” node . But eventually only the “rman shader” node 's shader can be rendered after I merge 2 objects together.
Does anyone know why? How can I have both “rman shader” and “shader” node to be rendered at the same time?
thanks!
"rman shader" node and "shader" node que
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- brucelay
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- old_school
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I can't quite tell what is going in with the description as there is only one Shader SOP but let's see if I can help.
I can thing of two things that could be wrong:
- One object A has shaders defined at the object level (or none whatsoever) and the other object B has shaders defined at the SOP level (Merge SOP). The geometry with the shader defined at the object level (A) merged in with the second geometry (B) will be missing shaders. Need to apply a Shader SOP to the first set of geometry at some point.
- Shaders are properly defined with Shader SOPs but one of the two is referencing a non-renderman shader.
You can effectively use the spreadsheet to inspect what shader strings have been applied to what geometry. First with the Merge SOP. If you either open up a spreadsheet pane or RMB on the Merge SOP's icon and select spreadsheet, choose to view primitive type attributes and inspect the shader attributes called “vm_ri_surface”. You will probably see some blank shader strings or some shader strings referencing non-renderman shaders.
The Merge SOP will create attributes to those inputs that are missing attributes on other data and they will be defined either as 0 for floats-ints-vectors or empty strings for string-types. The Merge SOP adheres to the fundamental requirement in Houdini SOPs that add data in a SOP chain (GDP) has the same attributes defined. The Merge will build attributes as needed and it can catch you.
It helps to distinguish between PRMan shaders and mantra shaders by applying prefix Labels to the dialog scripts like RMan_myshader. See rmands for useage and use the -N label option to specify the label.
I can thing of two things that could be wrong:
- One object A has shaders defined at the object level (or none whatsoever) and the other object B has shaders defined at the SOP level (Merge SOP). The geometry with the shader defined at the object level (A) merged in with the second geometry (B) will be missing shaders. Need to apply a Shader SOP to the first set of geometry at some point.
- Shaders are properly defined with Shader SOPs but one of the two is referencing a non-renderman shader.
You can effectively use the spreadsheet to inspect what shader strings have been applied to what geometry. First with the Merge SOP. If you either open up a spreadsheet pane or RMB on the Merge SOP's icon and select spreadsheet, choose to view primitive type attributes and inspect the shader attributes called “vm_ri_surface”. You will probably see some blank shader strings or some shader strings referencing non-renderman shaders.
The Merge SOP will create attributes to those inputs that are missing attributes on other data and they will be defined either as 0 for floats-ints-vectors or empty strings for string-types. The Merge SOP adheres to the fundamental requirement in Houdini SOPs that add data in a SOP chain (GDP) has the same attributes defined. The Merge will build attributes as needed and it can catch you.
It helps to distinguish between PRMan shaders and mantra shaders by applying prefix Labels to the dialog scripts like RMan_myshader. See rmands for useage and use the -N label option to specify the label.
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