Post-production with V-Ray (Matte Render Elements)

In our recent blog post, we mentioned that V-Ray during rendering process generates a lot of render elements that are divided into four major groups: Beauty Render Elements, Matte Render Elements, Geometry Render Elements, Utility Render Elements, and these elements can be used for post-production process. In this article, we’ll continue to develop the topic of post-production and discuss how Matte Render Elements and their usages can be useful in post-production process.


Matte Render Elements


The Matte Render Elements are used to select different objects and materials in the visualization by masking (marking) them with different colors. Matte Render Elements contains Material ID, Multimatte, Object and Render ID render elements.


Material ID Render Element. Based on their Material ID, the Material ID Render Element can read all materials used in visualization, identify them, and separate objects with specific materials for compositing purposes. Material ID Render Element offers an easy-to-select mask for specific objects and materials in compositing software. This render element is excellent for isolating geometry in a visualization so that it may be improved or adjusted during post-production process. Material ID Render Element either displays each material as a solid unshaded color (by Material ID) or stores the Material IDs as integer values.


The first image presents how Material ID Render Element separates different materials with different color channels. The second one displays Matte created in composite by using only the red channel representing the glass material.

The first image represents the original render. In the second image we can see how the view of the image changed when the glass was enhanced using Material ID Render Element red channel (as a mask in the composite).


The Multimatte Render Element provides red, green, and blue selection masks based on an object's Object ID or Material ID. Unlike other Matte render components, which can use a variety of colors to represent each material or item in a scene with a distinct color, this one use only three colors: red, green, and blue. Several Multimatte Render Elements can be created for a single rendering, each with separate Material ID or Object ID settings, to represent all the objects or materials in a scene with only the available red, green, and blue colors. Multimatte Render Element is useful for isolating geometry in a created scene. Multimatte Render Element is usually simpler to use in compositing software than other matte render elements since it is set to just include pure red, green, and blue channels to represent objects in the scene. Compositing software often has a feature for easily selecting the red, green, or blue channels in an image for use as mattes.


The first image presents the red, green and blue channels of the MultiMatte Render Element. The second one displays Matte created in composite by using only the blue channel representing the back wall.

The firs image represents the original render. In the second image we can see how the view of the image changed when the back wall was color-corrected using matte created from Multimatte blue channel (as a mask in composite).


Object ID Render Element creates selection masks based on Object ID and is useful for isolating geometry in a scene meaning that items can be isolated by use of a matte created from the solid colors within the Object ID pass. This element allows to isolate individual objects with color or integer values and is useful for marking geometry in a visualization based on the Object ID. If you wish to have both solid-shaded color and integer-based render components for maximum compositing flexibility, you may produce several passes for a single rendering.


The first image presents different channels of the Object ID Render Element. The second one displays Matte created in composite by using only the blue channel.

The first image represents the original render. In the second image we can see how the view of the image changed when dangling lamp was color-corrected using matte created from Object ID Render Element blue channel (as a mask in composite).