---
title: "GPU IPR Settings"
canonical: "https://documentation.chaos.com/space/VMAX/113587465/GPU%20IPR%20Settings"
format: markdown
---
This page provides information on the IPR Settings rollout in the V-Ray tab when V-Ray GPU is used as the production renderer.  Overview The IPR Options rollout is accessible through the  V-Ray tab  of the Render Setup window. These options determine the behavior of  Interactive Production Rendering (IPR)  in the  V-Ray Frame Buffer . UI Path:  ||Render Setup window|| >  V-Ray  tab >  IPR Settings  rollout ( Renderer  set to  V-Ray GPU) IPR Settings Start IPR  –  Opens the VFB and starts an interactive rendering.  Fit resolution to VFB  –  When enabled, manually resizing the VFB during rendering changes the rendering resolution that IPR uses, making the resolution match the newly resized window. When disabled, the IPR resolution is locked to the resolution set under the  Common  tab even if the VFB is resized. Use Render state in IPR  – When enabled, V-Ray GPU IPR will use Render states/counts/iterations/modes instead of viewport ones. Anima 4D assets require this option to be enabled in order to be rendered in V-Ray GPU IPR. IPR 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, but interactivity may be significantly diminished. Increasing this value also reduces amount of data transferred from the render servers back to client machine. Undersampling  –  When enabled, IPR starts rendering the image at a lower resolution in order to speed up the initial preview. Later the image is rendered at its final resolution. IPR ray bundle size  – These control the number of rays that are sent to the IPR render servers for processing when using IPR. When using distributed rendering, the smaller sizes cause more frequent client/server communication with smaller network packets thus decreasing the speed of the renderer but increasing the interactivity and vice versa. 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.