Procedural texturing and texture baking

[DASD]

Hi,

I have created a procedural model with procdeural UVs and with a procedural material (a procedural cop network fed into a standard material) and as the next step I want to add wear and tear, etc. and bake it to texture(s). [Different maps, like diffuse, normal, specular, etc.]

I am wondering how to do this best and I suspect I would need to get into shader programming to get anywhere near the results I want. For example, I have a selection of edges around which I want some random wear and tear. I tried resampling those edges - which was a nightmare, because I had to rebuild those edges as curves to get any sort of control - and copied geometry to them so that I could somehow bake it with micropoligon rendering. It was inefficient, to say the least.

I guess the only way to do this sort of thing in Houdini would be to cobble together some sort of shader that makes decisions based on attributes (?) at render-time. Do you have any in-depth tutorials for this sort of thing?

 

http://cargocollective.com/dimitrisCG/Procedural-Tank-Houdini-FX

[Robert]

I think the best way to approach this is to create multiple masks in your shader based on certain attributes and maybe even predefined groups.

You could then use these masks to blend your color with dirt maps or general noise to create the wear and tear effect. The hardest part here is to generate some usable masks. 

A way to get these is to import attributes from your mesh with the parameter nodes or with point clouds.

If you already had some groups where you wanted wear and tear you could assign attributes to them to identify them for your shader.

You could use some ambient occlusion-like approach to detect crevasses and indentations where dirt would gather.

It might be possible to identify edges of the geometry in the shader by comparing the normals of the current shaded point with the normals of other points inside a radius, if they changed a lot you probably got an edge or some other significant feature.

[DASD]

Thanks Robert. ^^ I had similar ideas, but I am quite fuzzy on the actual execution in Houdini... Can somebody point me towards shaders that do something remotely similar?

[Robert]

Try looking at eetu's work here: http://forums.odforce.net/topic/8471-eetus-lab/page-14

A similar topic on the sidefx forums: http://www.sidefx.com/index.php?option=com_forum&Itemid=172&page=viewtopic&t=13855&highlight=&sid=80e8bc81644c34491ea5e5673f2580ea

[DASD]

Thanks, man!