Global material override?

[oldiesgoodies]

Hi

What is the best way to do material override globally without changing the individual object`s shader affiliations? Basically I want to be able to render everything in my scene with clay type shaders without applying clay shader to all the objects.

thanks

[Erik_JE]

Disable surface shading in the Mantra ROP will give you kinda that result.

[Stalkerx777]

Or you can add shop_surfacepath path to ROP node, this will force mantra to use this shader for all objects.But this should be surface shader, not material.

[anim]

Or you can add shop_surfacepath path to ROP node, this will force mantra to use this shader for all objects.But this should be surface shader, not material.

I am not sure this will work since inheriting of properties prefer lower levels so surface shader on objects will always override ROP or Camera level surface shader if present

I usually create Take where I override material or just surface shader of all objects to desired one, This is just a matter of seconds in Parameter Spreadsheet so pretty straightforward

It's not that procedural though so if you add new object you need to override shader for that as well manually

Edited June 13, 2011 by anim

[Jason]

Take a look at Python Filtering -- in this post:

[oldiesgoodies]

Hi

Thanks for all the answers. It sounds like there is no straight solution to global override but as usual Houdini offers a lot of alternative methods.

thanks

[Jason]

If you look at the PythonFilter example code (which does almost the exact thing you're asking for) you'll see these two lines - the lines which actually set the new properties.

            mantra.setproperty('object:surface', 'matte')
            mantra.setproperty('object:overridedetail', 1)

The first line sets the new shader, the second line tells it to override any shaders set by Material SOPs and use the object:surface strictly.

For the first line, you can tell it to

(1) use a shader out of the OTL libraries -- in which case use: mantra.setproperty( 'object:surface', 'opdef:/Shop/plastic diff 1 1 1'.split() )

(2) use a shader in the IFD, which needs to be forced into the IFD using the mantra rendering property "Declare Materials"(declare_all_shops) set to "Declare All SHOPs"

I, too, wish a downstream property could be set to override upstream properties :-/