Table of Contents

This page provides information on the GPU rollout under the Render tab in V-Ray's Render Settings.

 

Overview

V-Ray GPU is a separate rendering engine on its own. You can use it as a production engine, and in an IPR mode. 

To use the GPU engine you need video card that supports following:

  1. CUDA 2.0 or higher

  2. The CUDA engine is supported only in 64-bit builds of V-Ray for Kepler-, Maxwell, Pascal-, Turing- or Volta-based NVIDIA cards.

  3. Hybrid Rendering (running CUDA on GPU and CPU) – V-Ray GPU CUDA rendering can be performed on CPUs and NVIDIA GPUs at the same time. Using the Select Devices for V-Ray GPU rendering tool you can enable your CPUs as CUDA devices and allow the CUDA code to combine your CPUs and GPUs to utilize all available resources.

UI Path

 

||Properties Editor|| > Render > Render tab > GPU rollout
(When Device is set to GPU in the Render rollout)

Parameters

GPU Device Type – Specifies one of the two engines to use for GPU rendering.

CUDA – A GPU engine based on the NVIDIA CUDA platform. This engine uses NVIDIA graphics cards that support CUDA and is the recommended engine for NVIDIA GPUs. Like the OpenCL engine, it can be very fast depending on hardware but has limited abilities with regards to shaders. The OpenCL and CUDA engines have the same set of capabilities. The recommended choice for NVIDIA GPUs.
Open CL – A GPU engine based on OpenCL. This engine uses graphics cards that support OpenCL and can be very fast depending on the hardware, but has somewhat limited abilities with regards to shaders. The OpenCL and CUDA engines have the same set of capabilities, but for NVIDIA GPUs it is recommended to use the CUDA engine.

Ray Settings

Resize Texture – Specifies the texture transfer mode for the GPU.

On-demand mip-mapped textures – Instead of loading all the texture files at their default resolution (original or resized), V-Ray will load the textures as needed and will automatically create mip-map tiles for them (regardless of their texture type). As a result, the GPU memory consumption could be decreased; textures that are not visible will not be loaded, and textures that are further away from the camera will be loaded with lower resolution. During the texture-detection process, V-Ray GPU will render slower. Once it detects that all textures are loaded, it switches automatically to the traditional (faster) mode. Supported only on CUDA.
Resize Textures – Adjusts the size of high-resolution textures to a smaller resolution in order to optimize render performance. 
Full-Size Textures – Transfers textures "as is". Does not resize textures and does not use paging.

Size – When the Resize Textures parameter is set to Resize Textures, this value specifies the resolution to which the textures will be resized. This also controls the resolution for baking unsupported procedural textures to bitmaps so they can be loaded into memory.

Format – The amount of bits per channel used to store the material texture information into memory. This does not affect textures used for lights and displacement.

8-Bit – 8 bits of data used per color channel.
16-Bit – 16 bits of data used per color channel.
32-Bit –  32 bits of data used per color channel.

Ray Bundle – Controls the number of rays that are sent to the V-Ray RT render servers for processing. When using distributed rendering, smaller sizes cause more frequent client/server communication with smaller network packets, thus decreasing the speed of the renderer but increasing the interactivity. Conversely, larger sizes increase the speed of the renderer but decrease interactivity. Note that this number is not the exact amount of rays, but is proportional to it. It is not recommended to increase this value beyond 512.

Rays Per Pixel – The number of rays that are traced for each pixel during one image pass. The greater the value, the smoother the picture from the very beginning of the rendering with GI. Increasing this value also reduces the amount of data transferred from the render servers back to the client machine.

Termination Settings

 

Time (min) – Specifies the maximum time (in minutes) for refining the image.

Paths / Pixel – Specifies the maximum samples per pixel for refining the image. V-Ray performs adaptive sampling on the image, trying to put more samples into areas that have more noise.

Noise – A threshold that determines when to stop refining a pixel. Higher values allow more noise in the image, while lower values try to reduce the noise. A value of 0.0 traces the entire image unconditionally.