[Arnold] Point World/Pref in a shader

[Malak1000]

Does anyone know how to get Point World/Pref in a shader (not an AOV) in HtoA? I'm trying to make a worldspace height mask.

Embarrassingly I can get it fine using MayaSamplerInfo3D but it feels dirty (and presumably horribly unoptimised) to do it.

Thanks!

 

[Malak1000]

Anyone?

[pclaes]

For future reference (including for myself   ).

In sops (assuming stable point count), create a timeshift node and set the frame to the rest/reference frame.

Then create a rest sop, append an attribute rename and rename 'rest' to 'Pref'.

You can then bring that Pref attribute into the shader with a user_data_rgba - and plug it into the position sampling of your noises.

Also on the rop you can export the Pref aov.

-- In your shader there is also a utility vop that has a 'p' option, but that won't give you a reference/rest position.

[Verville_Pierluc]

To get it make work by default with HTOA or MTOA, make sure your "Pref" attribut is set as 3 float *position*. 

https://docs.arnoldrenderer.com/display/A5AFHUG/Noise

**completely down the page**

[paranoidx]

I reply for future reference: 

Just put a REST sop node for no animation geometry.

In Arnold Shader VOP network, use "rest" at Pref. No need import anything, automatic pickup the rest attribute. (The same with Houdini RenderMan 26)

Arnold version: 7.2.5.1

HTOA 6.2.5.1