This page provides information on the MultiMatte Materials Render Element.
The MultiMatte Materials Render Element creates red, green, and blue selection masks based on material's ID number. Please note that this channel does not take into consideration Material's ID color.
With this render element, only three colors are possible: red, green, and blue. It analyzes the scene at render time and automatically creates the necessary number of channels based on the number of unique specified IDs. Each channel holds up to 3 unique IDs. Each channel's name indicates the IDs it represents.
With MultiMatte, a single R, G, or B channel can be used directly as a matte, eliminating the step of selecting the color in the compositing software. This ease of use makes MultiMatte a popular choice for compositors.
The MultiMatte Materials Render Element includes an antialiasing option.
Beside this render element, V-Ray also supports MultiMatte Objects channel, which uses Object ID numbers.
||V-Ray Asset Editor|| > Create Asset > Render Elements > MultiMatte Materials
||V-Ray Asset Editor|| > Render Elements (right click) > MultiMatte Materials
How to Set Material IDs
Material ID numbers can be set from the Asset Editor. Go to the material's parameters and make sure to select the Advanced mode, as shown in the example. A Material ID rollout appears, where you can set an ID number. You can select one ID number for more than one material in order to create a group of objects in the MultiMatte channel.
All items with the material assigned will be colored in the same color in this channel. See the result below.
Setting Material ID number
Render result from the MultiMatte Material channel