diference between Along vertical & Vertical only

[TheBadger]

Displacement will happen along the normal of the underlying object (i.e. the planet or a model) without any displacement being applied

How does displacement happen "without any displacement being applied"? I don't understand the quote.

Displacement only happens along the normal of the underlying object (i.e. the planet or a model).

This makes sense to me. if object means the surface of my planet... Does it?

but

The displacement is scaled by the difference between the object normal and the surface normal. Displacement is reduced as the angle between the normals approaches 90°.

this part does not make sense to me.

What is the difference between " the object normal" &  "the surface normal"? What is the object and what is the surface in a scene?

And why does the displacement not remain constant but only in the vertical? Or rather, I would expect that the displacement is constant, but limited to the vertical, and therefore, more visible as a slope reaches 90 degrees.



All quotes are from the wiki regarding the displacement shader.
http://www.planetside.co.uk/wiki/index.php?title=Displacement_Shader

[Tangled-Universe]

My guess is that the planet is the underlying object you refer to.

The compute nodes evaluate how the nodes alter the surface of the starting primitive object (planet, by default).

The primitive has it's own normals and the displaced surface has its own "new" normals.
(features like "intersect underlying" utilize the differences between these "states" of the surface by comparing computed surface normals vs normals of underlying object)

[russe166]

Hi!

Did you have a look on this page?

http://www.planetside.co.uk/wiki/index.php?title=Power_Fractal_Shader_v3_-_Displacement_Tab

[Oshyan]

I've updated the description on that wiki page a bit as I agree it was confusing. That first quote is basically just trying to say that the displacement happens based on the "original" normals of the object/surface, prior to any displacement having been applied.

- Oshyna

[TheBadger]

Thanks Much fellas.

TU
I am glad you mentioned intersect underlying. I felt that this is the next part of what I am trying to do intuitively. So you gave me some conformation confidence. Of course, intersect underlying is a node with lots of questions too.