This page provides details on the Environment settings in V-Ray for Unreal.
Page Contents
Overview
The Renderer tab provides convenient access to common Rendering functions such as choosing the render devices or sampler. You are also able to choose from several Quality presets of the Geometry Tessellation, the GI primary and secondary engine and adjust the Interactive renderer's settings, as well as choose the auto-save file path for your renders.
Parameters
Engine – Switches between CPU and GPU rendering engine. GPU enabled unlocks the menu on the right, where you can select which CUDA device(s) to perform the raytracing calculations or combine them for Hybrid Rendering. The Computer CPU is also listed as "C++/CPU" in the CUDA device list.
Sampler – Selects the image sampler type. For more information on how the Sampler works, see the Sampler page.
Progressive – This is the default image sampler set in V-Ray for Revit. It renders the entire image progressively in passes.
Bucket – This sampler takes a variable number of samples per pixel based on the difference in intensity between the pixel and its neighbors.
Global Illumination
Global Illumination allows for selecting a primary and secondary GI engine.
There are several ways to combine primary and secondary GI engines in V-Ray for Revit.
1. Brute Force + Brute Force – very accurate but slow
2. Brute Force + Light Cache – accurate
3. Irradiance Map + Light Cache - very fast
4. Irradiance Map + Brute Force - fast
GI Depth – Specifies the number of light bounces that will be computed. GI Depth will also be used to calculate Interactive rendering GI Depth.
For more information on Global Illumination, see the Indirect Illumination Reference page.
Interactive Settings
Trace Depth – Represents the maximum number of bounces that will be computed for reflections and refractions. The individual material reflection/refraction depth settings are still considered, as long as they don't exceed the value specified here.
Ray Bundle Size – Controls the number of rays that are sent to the V-Ray Interactive render servers for processing. 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. 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, but interactivity may be significantly diminished. Increasing this value also reduces the amount of data transferred from the render servers back to client machine.
Undersampling – When set to a value greater than 0, during interactive updates, the image is rendered initially at a lower resolution in order to speed up the preview of the updates. Once you stop updating the model, the image is rendered at its final resolution The optimal value for Undersampling is the default one.
Optimizations
Adaptive Lights – Optimizes the sampling of lights in scenes with many lights.
Bucket Size – Determines the maximum bucket width in pixels when the Sampler is set to Buckets.
Geometry Tessellation
This affects the tessellation of the geometry in each of the quality presets ranging from 0-15. Higher values result in geometry from Revit having more polygons. Lower values decrease render times but result in round geometry appearing to be more jagged in appearance. Values at and close to zero create odd situations such as round columns appearing to only have 4 or so sides.
Auto-Save
When Auto-Save is Enabled V-Ray will save automatically completed renderings to a specified location.
All selected render elements will also be saved.
Once Auto-Save is enabled, you can browse for a folder where completed renderings will be saved. From the browsing dialog, you can also select the file format of the auto-saved images.
Hybrid Rendering with CPUs and the CUDA Engine
Starting in 3.60, V-Ray GPU can perform hybrid rendering with the CUDA engine utilizing both the CPU and NVIDIA GPUs. V-Ray can now execute the CUDA source on the CPU, as though the CPU was another CUDA device. To enable the hybrid rendering mode, simply enable the C++/CPU device from the list of CUDA devices.
The hybrid rendering mode does not require any special drivers. Furthermore, you can use the CPU as a CUDA device even if you don't have an NVIDIA GPU and/or NVIDIA drivers installed. Meaning, this mode can be used on computers that don't even have GPUs. The hybrid render engine running on a CPU supports the same features as the regular V-Ray GPU CUDA engine.
Interactive GPU OpenCL rendering mode is currently not supported.