MDL Displacement brick

Oso3D

I'd really like to modify displacement in shader, but... absolutely nothing seems to pipe into the Displacement Strength input. It seems like it SHOULD be able to accept any Mono image output... but... no.

 

Any ideas?

 

Esemwy

I don't have any of my materials in front of me, but I believe you need to convert color maps to luminance values. Once you've done that, I believe you can use it as displacement. 

jag11

I also need to figure this out, need it for my snow material.

Tobor

Not sure I understand the problem. Iray Uber shows how Displacement Strength can take a map. The output pipes to Displacement Strength Map.  Or are you saying you've done, but you don't get the expected result when you apply a grayscale image?

Oso3D

Displacement Strength Map won't accept output from anything other than the user parameter. I've tried just about every other output, plus Perlin Noise, and other things... just, nope, cannot connect.

If I try to pipe, say, Perlin noise to the Geometry brick as Displacement, it does... bupkis. No displacement.

 

Oso3D

And WOW Shader Mixer could use a Brick Search function. And wow, is there really no f'in documentation saying 'X brick does Y'? Sheesh.

 

Oso3D

Oh hey, Perlin Bump Noise actually outputs something displacable! Woot!

 

Now to figure out how to sew it together...

agent unawares

timmins.william said:

And WOW Shader Mixer could use a Brick Search function. And wow, is there really no f'in documentation saying 'X brick does Y'? Sheesh.

 

There is. It's just from NVIDIA.

http://www.nvidia-arc.com/fileadmin/user_upload/iray_2013/documents/MDL_spec_1.1.3_11Jun2014.pdf

http://www.nvidia-arc.com/fileadmin/user_upload/iray_documentation/nvidia_mdl_introduction.140512.LTR.pdf

(No search that I know of, but you can set the language filter to MDL to get rid of the 3Delight bricks at least.)

Tobor

If you are using the Iray Uber MDL, keep in mind that there are conditional statements throughout it that "shut off" shader features to prevent them from over-complicating the rendering process. Example: For displacements, you can see there is a boolean (true/false, or on/off) value associated with the Material_Add_Geometry brick, and that for displacement to occur, the displacement enable flag must be set true. This type of thing is ordinarily done by modifying some user-facing input node in the shader, such as applying a texture to the displacement channel. Only when that's done will the displacement effect take place.

Texture inputs automaically apply other values that might be needed, such as texture coordinates, which come from the surface tiling brick. If you're using an arbitrary source for the displacement, there's no telling how that will interact with the tiling, which in turn controls the displacement mapping and finally the procedural geometry.

An example of the shader and MDL you're using would be useful.

Oso3D

Agent: Those documents are... very limited.

 

Fishtales

This help?

http://www.mdlhandbook.com

Click on the headlines to get the pages.

or

http://www.migenius.com/articles/mdl-diamonds

Oso3D

Not really, but I'm getting some potentially useful results. Displacement works rather differently than the other bricks.