Search Keywords: light material, self-illumination
The VRayLightMtl is a special material provided with the V-Ray renderer. This material is generally used for producing self-illuminated surfaces. It also allows faster rendering rather than with a Standard 3ds Max material with self-illumination enabled. It also allows to turn an object into an actual mesh light source.
Color - this is the self-illumination color of the material.
Multiplier - this is the multiplier for the Color. Note that this does not affect the texture map, if specified.
Texture - a texture map to use for the self-illumination color.
Opacity - a texture to use as opacity for the material. Note that making the material less opaque does not affect the intensity of the self-illumination color. This is so that you can create perfectly transparent materials that nevertheless still emit light.
Emit light on back side - checking this option makes the object emit light from its back side as well. If this is off, the material is rendered as black on the back sides.
Compensate camera exposure - when enabled the intensity of the light material will be adjusted to compensate the exposure correction from the VRayPhysicalCamera
Multiply color by opacity - when enabled the color of the light material is multiplied by the opacity texture
Displace - allows the user to add a displacement map to the V-Ray Light Material.
The controls in this section allow you to turn the objects which have this VRayLightMtl material applied into actual direct mesh light sources. The effect is equivalent to creating a VRayLight in Mesh mode for the same object. The controls in this section are intentionally simple; if you need more control over the light source (exclude objects from illumination etc), it is better to use a VRayLight instead.
There are currently some restrictions on using these options. For more details, please see the Notes section below.
On - when enabled, turns any objects with the same material into mesh light sources. Note that this currently does not work if the material is inside a Multi/Sub-object material.
Subdivs - controls the number of samples used for direct sampling of the mesh light. Lower values may be faster to calculate, but may introduce noise in the image. Higher values reduce the noise, but increase render times.