Procedural mountainside (displacement and normal issues)

[lukeiamyourfather]

The last few months I've been getting up to speed with Houdini at work, so if this is a dumb question please be gentle! Right now I'm working on a shader for a mountainside, specifically a displacement VOP SHOP that will have relatively smooth dirt in level areas and rocky displacements in steep areas. Its using the dot product of the geometry surface normal and a vector for up (0, 1, 0), then that value is multiplied with some noise and plugged into the amount for a displacement VOP. More or less its working but with some issues.

It only looks right from one camera angle. As soon as its rendered with the camera moving around the displacement is constantly changing as if it were using the facing ratio or something else instead of the normal on the mountainside geometry to determine displacement. I've tried both N and Ng from the global inputs but they both seem to do the same thing when the camera is moving, is Ng not what I think it is (same as the normals in a SOP for the surface)? Attached is an image of the displacement network. Thank you very much for checking it out.

[stevenong]

Hi,

First of all, welcome to odforce!

You need to use a Rest Position VOP in place of the Global Position values.

Check out this post by old_school.

In addition, you can search through the forum with "+rest +position" as the keywords to get more posts related to it.

Cheers!

steven

[lukeiamyourfather]

Hi,

First of all, welcome to odforce!

You need to use a Rest Position VOP in place of the Global Position values.

Check out this post by old_school.

In addition, you can search through the forum with "+rest +position" as the keywords to get more posts related to it.

Cheers!

steven

Thank you very much for the warm welcome and the help!