MEOW: Material Overrides

The general logic of material assignment in Multiverse works this way:

• Shape assigment When you create a Compound in Maya it will be by default connected to the Maya default shading engine (lambert1). This is called shape level material assignment. You can assign another material other than lambert1 of course: without any further override the compound will render with this material and use the material for all items in the compound.

  Note:::

  An exception to this is when reading a USD file in the compound and rendering with 3Delight NSI: in this case the compound will be rendered with the look of usdPreviewMaterial defined in the USD file.

With the word "materials" we actually refer to Maya shading groups (shadingEngine nodes), special type of Maya nodes that collect both the surface shader and displacement shader information. These shading group can come either from Maya itself, or from UDS shading networks. :::

To assign a material in MEOW, select one or more items, then from the material context menu via RMB click select Assign: MEOW will list new and existing materials available for assignment.

Note

If the your rendering plugin for Maya is not loaded, then MEOW won’t allow show the renderer relative materials until the plugins are loaded.

We can assign both new materials and existing materials from the list of assignments. If there are supported materials in the scene it will list the existing shading groups in the Existing menu item in each renderer section.

Material Information

Hovering the mouse pointer (no click) on a material icon will show the material shading group name:

When reading an USD file that was written with material assignment, MEOW will show that a material is assigned with a gray colored icon.

If we want to edit the assigned material properties we can use Inspect Material from popup menu when active and it will show Maya’s attribute editor for that particular material.

TODO: Add Show node editor here

Material Assignment Rules

Here are the default material assignment rules for a Compound:

• If there are no material assignments at all in MEOW, the Maya material assigned to the Compound shape node via its shading group will be used for rendering.

• An exception to the above rule is if the USD file in the Compound contains USD preview materials and you are rendering with 3Delight^NSI: in this case the compound will be rendered with the look of usdPreviewMaterials defined in the USD file. This behavior can be overridden by assigning material overrides in MEOW or by disabling embedded usd materials using the relative compound shape node option.

• If there’s already a material assignment written in the USD file (gray icon) use that material, as long as it exists in Maya and is not further overridden in MEOW or on another above layer with material assignment overrides.

• If an item has a material assignments override in MEOW: this material will be used for rendering as long as it exists in Maya (maya override -- green icon) or in USD (usd override -- blue icon).

• Children inherit material assignment from their parents.

• USD material assignments can be disabled from the compound shape node.

Material Assignment Order

When assigning materials, please note that there are order of importance of which materials will take precedence over another.

1. The material assigned directly to the mvUsdCompoundShape is the material used for items which have no overrides. By default when creating a new Compound this is lambert1, but you can assign any other material to the shape node.
2. If there is a material assigned on the root item in MEOW, then it will override material assignment from 1. All children of root will inherit this material if not overridden below.
3. If an item specifies a material assignment (gray icon), then it will take precedence over 2 (and all children will inherit if not overridden below).
4. If an item specifies a Maya material override (green icon) or a USD materuial override (blue icon) and you are rendering with 3Delight^NSI, it will take precedence over number 3.

Removing Materials

Select items and then click Remove from MEOW popup menu.