This page provides information on V-Ray compatibility with G-Buffer output.
Overview
V-Ray supports multi-layered G-Buffer output required for writing .rla and .rpf files, as well as by many 3ds Max render effects. V-Ray automatically generates the G-buffer channels requested by the image output and the render effects so there is no need to select these manually.
Supported G-Buffer Channels
This is a list of supported G-Buffer channels in 3ds Max.
3ds Max Channel Name | Supported by V-Ray | Description |
Z | YES | Depth buffer (distance to the camera XY plane). |
Material Effects | YES | The material ID. |
Object | YES | The object node ID that is set through the Properties dialog of an object. |
UV Coordinates | YES | The surface UV coordinates. V-Ray always outputs the UV coordinates for mapping channel 1. |
Normal | YES | The surface normal relative to the camera. |
Non-Clamped Color | YES | The real unclamped pixel color, before any color mapping is applied to the pixels. Like with the scanline renderer, this channel does not store atmospheric effects. |
Coverage | YES | The contribution of an object to the image pixel. |
Node Render ID | YES | A unique ID assigned to each node by the renderer. |
Color | YES | The material color for the object. Like with the scanline renderer, this does not include any atmospheric effects. |
Transparency | YES | The material transparency for the object. Like with the scanline renderer, this does not include atmospherics. |
Velocity | YES | The surface velocity relative to the camera. |
Sub-Pixel Weight | YES | The contribution of an object to the image pixel including transparencies. |
Sub-Pixel Mask | NO | A bit mask for the contribution of an object to a pixel. The Sub-Pixel Mask channel is meaningless when AA filters, depth of field, and motion blur are taken into consideration, which is why V-Ray does not support it. |
Notes
- V-Ray takes antialiasing filters into account when generating the G-buffer channels, in contrast with the default scanline renderer of 3ds Max. This may cause differences in the way some render effects work. If this is a problem, turn off the AA filter from the Image sampler rollout. Also, avoid using AA filters with negative components (Catmull-Rom, Mitchell-Netravali) when generating a G-buffer; 3ds Max cannot handle layers with negative coverage and V-Ray ignores those when creating the 3ds Max G-buffer.
- Generating a correct multi-layer G-buffer requires extra memory. This is because the 3ds Max G-buffer only supports scanline-style writing. However, V-Ray renders in buckets and cannot provide the data in scanline order. To work around this, V-Ray stores all the G-buffer data while rendering and then writes it at once into the final image.
- G-Buffer layers are now generated correctly in distributed rendering mode. This means that render effects like image motion blur now work in DR mode too.