This page provides information on how Displacement works in V-Ray for Maya.
Overview
Displacement is the deforming of geometry based on pixel values in a texture map. This can help create more detail on geometry at render time while allowing objects in the viewport to be lighter and easier to work with.
Displacement is different than traditional bump mapping because it alters the actual polygons on the geometry to add detail. Displacement can also change the edges and silhouette of the geometry, which is not possible with the lighting tricks used by bump or normal mapping.
The VRayDisplacement node can be used to control the displacement on geometry objects. The node behaves like a Maya Set and can be found in the Outliner or the Set Editor where other objects can easily be added to the set. This provides flexibility when combined with the Subdivision and Displacement Quality and Displacement Control Extra Attributes, which control displacement on a per-object basis instead of every object having the Default Displacement settings. These Extra Attributes can be added to an individual object node to affect the displacement of one object, or they can be added to a VRayDisplacement node to affect several objects together (similar to a Shading Group node). This rendering technique is available in both V-Ray and IPR renderings as long as the Displacement option is enabled under Geometry Overrides in the Render Settings window.
To add a VRayDisplacement node, select the desired mesh(es) and use one of the UI Paths below to create the Maya Set used for the Displacement. Then you can add the Subdivision and Displacement Quality and Displacement Control Extra Attributes to the VRayDisplacement node to further control the displacement for the selected meshes.
||Select mesh(es)|| > V-Ray Shelf > Right-click V-Ray Displacement
||Select mesh(es)|| > Create menu > V-Ray > V-Ray Displacement > (select desired option)
Menu Options
Since there are multiple options available from the V-Ray Displacement menu, here is a simple breakdown of what they do. Note that objects can only be associated to one displacement set at a time.
Apply multiple VRayDisplacement to selection – Creates a separate VRayDisplacement set for each object selected. The naming of the sets will use the object names as a prefix (i.e. pShere1_vrayDisplacement). This option errors out if nothing is selected.
Apply single VRayDisplacement node to selection – Creates one VRayDisplacement set that stores all the selected objects inside of it. This option errors out if nothing is selected.
Note: When using the Apply single/multiple options any previously connected VRayDisplacement nodes are disconnected.
Remove VRayDisplacement from selection – Disconnects the selected object from the VRayDisplacement set it is linked under. This does not delete the displacement set.
Remove VRayDisplacement from selection and sub-hierarchy – Disconnects the selected object and all levels of children it has under it from any VRayDisplacement set they are linked under. (Useful if multiple objects under a group node or other hierarchy are linked to multiple Displacement Sets because selecting the group node and choosing this option disconnects all objects from all Displacement sets within the group.)
Force create VRayDisplacement node – Creates an empty displacement node if no objects are selected. Useful for manually adding objects to the Set from the Outliner.
Parameters
Override Global Displacement – When enabled, the texture in the VRayDisplacement node is used, in case there is also a texture specified in the Shading Group node connected to the same object(s).
Displacement mat. – Specifies the displacement texture.
Workflow
Below is the basic workflow used for setting up V-Ray Displacement.
1) Add the VRayDisplacement node to the selected object(s), using the V-Ray Shelf or Create Menu. This adds a Maya Set to the Outliner that includes the selected object(s). In the screenshot below, the Apply single VRayDisplacement node to selection option was used, but the menus allow separate nodes to be created for each selected object as well.
2) Assign a map to the Displacement mat property in the Displacement node. This is typically a texture map, but can also be a procedurally generated one as well.
3) Add Extra Attributes to fine tune the Displacement Quality, Displacement Control, and/or Subdivision settings.
4) Additional objects can be added to the Displacement Set in the Outliner to receive the same displacement values.
32-bit Displacement Maps
If you are using 32-bit Displacement maps generated from an external sculpting application, make sure to add the Allow negative colors V-Ray texture attribute to take advantage of the whole range of data saved in your file.
Notes
- Subdivision and Displacement Control extra attributes may be added to the displacement node to control all objects within that displacement Set together.
- When using the options to apply a single or multiple VRayDisplacement node any previously connected VRayDisplacement sets will be disconnected, because objects can only be linked to one Displacement Set at a time.