Converting a generic / standard material to VEX format?

[rd1010]

I'm trying to learn more about VEX shaders and how to create them and am wondering if there is a way to take a standard material, such as reflective, chrome, etc and then put it into the VEX network so it shows as a VEX shader... as someone pointed out in another post, I see now how I can view the type properties and also how to create a digital asset from it and view it that way but I would like to get it into the shader format within the VEX area so I can view it that way to better understand how to create the VEX shaders

Thanks for any help

[Ratman]

Drop down the shader form the material palette, and in a network view go to the shops tab, select that node, press enter or i to dive into the material and then select the surface portion, and press i or enter again, and there you have it, the vop network of the shader.

[rd1010]

Thanks for the quick response

Edited September 4, 2009 by rd1010

[Ratman]

No problem, I was in the area

[rd1010]

It seems its not possible to dive into the shaders that come with houdini such as the "vex layered surface" or "vex super material"... is there a reason for this and it actually is not possible at all or is there a way to get into it?

Edited September 5, 2009 by rd1010

[DaJuice]

Hi rd, I'm pretty sure it's because these were written in straight VEX. On the other hand, all the shaders in the Material Palette (as opposed to what's available in the SHOPs tab menus) were constructed in VOPs. You can dive inside them and check out the vopnets. The Material node is sort of analogous to an .avi or .mp4 container, except instead carrying video and audio streams it contains surface shaders, displacement shaders, etc.

It seems its not possible to dive into the shaders that come with houdini such as the "vex layered surface" or "vex super material"... is there a reason for this and it actually is not possible at all or is there a way to get into it?

[edward]

I think you're missing some fundamental concepts about shaders in Houdini. The two most popular renderers used with Houdini are PRMan and Mantra. In both cases, they use a "shading language" (ie. code) that is somewhat "compiled" and executed while rendering. VOPs in Houdini is a graphical method for creating these shaders. Behind the scenes, the shading networks are converted into the "shading language" (RSL for PRMan, VEX for Mantra), which are then "compiled" and passed to the renderer. You can easily see what code gets generated if you right-click on any of the VOP nodes inside and choose "View VEX Code". You will notice that there are comments for each VOP, showing the code that was generated.

The default "VEX ...." SHOP nodes are only defined by code (such as when you right-click on them, choose ). Why is that? Because they were written before VOPs existed. In order to see the VEX code for it, you can right-click on the "VEX ...." SHOP and choose Type Propertices. Now switch to the "Code" tab. With some work, it's possible to take this node and create the VOP network as well but you might as well just look at the code to draw inspiration from for your VOP networks.

It seems its not possible to dive into the shaders that come with houdini such as the "vex layered surface" or "vex super material"... is there a reason for this and it actually is not possible at all or is there a way to get into it?

[rd1010]

Thanks.. yeah I kind of gathered that just recently about the shaders being written just in code, I should be able to figure out the coding from looking at it as I have some experience with programming so I'll try that as I'd really like to figure out how they laid out the transparency maps since its not exactly intuitive how to do it in the VOP network.

Edited September 5, 2009 by rd1010