Convert Blender3D Shader

[r1ver]

is it possible to convert some Blender3D shaders, such as this one: www.youtube.com/user/sterlingschiffdesign

looks very cool!

do anyone know how to make a similar network in Houdini, pls see the attached Blend3D network, thanks!

[old school]

Yes you can mix BSDF's in Houdini, no issues, for all render engines. You can add them as well. And have them work with both render engines: PBR and raytrace. My example below is set up for PBR as I am using the F term in the VOP network.

Here's the most simple way of executing pretty much exactly what the Blender network is doing for PBR:

And the scene file:

minimal_carpaint_shader.hip

Personally I would not construct the network this way as you don't set yourself up for per-light exports of all the various shader components. It uses the older Lighting Model VOP simply because it has a colour parameter simplifying the network to get close to the blender network as you requested.

If you wish to see one way to construct such a network, have a look at the Shading Model VOP, dive inside and look at the Reflection 1 network box as it contains the VOPs used to construct a reflection coat layer with both base and clear coats.

One thing missing but not used in the Blender model is a user defined fresnel based on facing angle. That can be added with the Alpha Mix VOP which uses Alpha parallel, Alpha Perpendicular for intensity and a roll to control how the reflections appear on the surface. I added this to a second shader in the hip file.

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Looking at this network, there is a nice improvement you can make. The way that you mix the two base paint layers to get an interesting rough metallic look is via a basic mix node and using the roughness parameter on the two reflection BSDF's. One thing you could try is to use a second fresnel term to mix these two or three base metallic layers. With rough metals, the IOR could be anywhere from 7 to 30. Whatever gets you the desired look or to match a real paint coat. Implemented in the third shader in the attached scene file.

At a metallic base ior of around 4, you get pretty much the same result as the base BSDF mixing. Then you can go below 4 to get a darker look or higher to emphasize the bright color. It lends itself to a more organic look when the car is in movement and just gives you a bit more control than using just the roughness terms for the BSDFs and the crude constant mix value.

There are just so many ways to implement a car paint shader these days. One of the criteria for a car paint shader depends on whether you have to mimic an actual paint on a car (no measured BSDF support in VOPs/Mantra yet...) or if this is for your own car paint and want it to look nice with your own ways to dial in your look.

[r1ver]

you are my hero!

[jonp]

Jeff hasn't mentioned the best part: just like OSL intends to do, creating multiple BSDFs incurs a very small performance penalty for the final render. I'm a bit old school myself and was used to the old way where mixing many lighting models can cause render times to explode... only recently did I find out that this is not the case in PBR.

Probably its best feature IMHO!