Rainfall and wetmap on vray displacement mapped object?

[dbakewel]

Hi there.
Do I need to set anything specific to get rainfall AND a wetmap to collide correctly on a plane that has been displaced using the Vray displacement node?
I can't seem to find anything in the manual about this kind of collision (unless i've been skim reading too quickly!)

Does phoenix just know about an object if it's been displaced and take that into account automatically?
Thanks

(using maya 2020.4 & Vray 5.10.22 & PFD 5.2

[georgi.zhekov]

Hey,

Unfortunately at the moment this is not possible. The displacement is a render time effect, while the the wetmap is born during the simulation (before the rendering starts).
The wetmap has no way to know if the surface is displaced or not.

[dbakewel]

ok, thanks for letting me know.
and just for the record, there's no way to "bake out" a displaced object (at render time), in a similar way to how arnold can?
Maya - Arnold: Displacement Baking (youtube.com)

[georgi.zhekov]

There is an experimental feature that lets you bake the displacement to a vrmesh file, but it comes with quite a few limitations compared to the regular displacement workflow.

Unfortunately this still won't do the job for your case as Phoenix doesn't support properly interactions with V-Ray Proxy objects (it might work for the liquid somewhat, but won't create wetmap particles).

If you still wish to give it a go you can use a post-translate script in the Render Settings menu > Common tab > MEL/ Python callbacks:

from vray.utils import *

node = findByName('pPlaneShape1@node')[0]

node.set('bake_subdiv_filepath', "path_to_file.vrmesh")

where you need to replace pPlaneShape1 with the name of your geometry node and the path to file with the output location of the file, note that you still need to give the file some name.

When this post-translate script is present and you press render - the geometry will be exported and rendering of the image will be skipped.