This page contains information about the Raytrace and Anti-aliasing settings.

 

Page Contents

 

Overview


 

In V-Ray, an image sampler refers to an algorithm for calculating a pixel's color based on the colors within and around it.

Each pixel in a rendering can have only one color. To get the color of a pixel, V-Ray calculates it based on the object's material, direct light striking the object, and indirect lighting in the scene. But within a single pixel there might be multiple colors, which may come from multiple objects whose edge intersect at the same pixel, or even difference in brightness on the same object due to changes in object shape or falloff and/or shadowing of light sources.

To determine the right color for such a pixel, V-Ray looks at (or samples) colors from different parts of the pixel itself as well as the pixels around it. This process is called image sampling. The settings that are available change based on turning on Interactive, Progressive and GPU Acceleration from the Renderer rollout.

For more information on how antialiasing works in V-Ray, see the Antialiasing in V-Ray page.

The Raytrace rollout provides controls related to sampling methods and anti-aliasing filters.

 


Image courtesy of Tuna Unalan

Multiple colors within a single pixel. What color should the pixel be? 

 

 


 

UI path: ||V-Ray Asset Editor|| >  Settings > Raytrace

 

 


 

 

Interactivity


The Interactivity setting is only available when the Interactive Renderer is turned on.

 

 

 

Interactivity – Controls the number of rays that are traced for each pixel during one image pass.  The smaller the value, the smoother the picture from the very beginning of the rendering with GI, but interactivity might be significantly diminished.

 

Quality


The Quality settings are only available when the Interactive Renderer is turned off. 

 

 


Interactive Off and Progressive On Advanced UI

 


Interactive Off and Progressive Off Advanced UI

 

 


Noise Limit – Specifies the acceptable level of noise/grain in the rendered image.  The smaller the number, the higher the quality (less noisy) the image will be.

Time Limit (minutes)  – Specifies the maximum render time in minutes. When the number of minutes is reached, the rendered stops. This is the render time for the final pixels only; it does not include any GI prepasses like Light Cache, Irradiance Map, etc. 

Min Subdivs – Determines the initial (minimum) number of samples taken for each pixel.  This value rarely needs to be higher than 1, except in the case of very thin lines or fast moving objects combined with motion blur.  The actual number of samples taken is the square of this number.  For instance, a value of 4 subdivisions produces 16 samples per pixel.

Max Subdivs – Determines the maximum number of samples taken for a pixel.  The actual number of samples taken is the square of this number.  For instance, a value of 4 subdivisions produces 16 samples per pixel.  Note that V-Ray may take less than the maximum number of samples if the difference in intensity of the neighboring pixels is small enough.

Shading Rate  – Controls how many rays will be used for calculating shading effects (e.g. glossy reflections, GI, area shadows, etc) instead of anti-aliasing. Higher values mean that less time is spent on anti-aliasing, and more effort is put in the sampling of shading effects. 

Bucket Size  – Determines the maximum region width in pixels (Region W/H is selected) or the number of regions in the horizontal direction (when Region Count is selected).

 

Antialiasing Filter


This section of the Raytrace rollout is only available when set to Advanced Settings mode ().

 

 

 

The Antialiasing Filter only shows in the advanced settings when Interactive is turned off.


Antialiasing  Filter – Enables or disables anti-aliasing.

Filter Size / Type – Controls the strength of the anti-aliasing filter and the type of anti-aliasing filter to use. For more information, see the Anti-Aliasing page for examples.


GPU Textures


This section of the Raytrace rollout is only available when set to Advanced Settings mode () and the engine is set to GPU. 

 

 

 

Resize – Enable this option to resize high-resolution textures to smaller resolution in order to optimize GPU memory usage.

Full-size textures – Textures are loaded into their original size. 
Resize textures – Adjusts the size of high-resolution textures to a smaller resolution to optimize render performance. 
On-demand mipmapping – Instead of loading all the texture files in their default resolution, V-Ray loads the textures as needed and automatically creates mip-map tiles for them. As a result, the GPU memory consumption is decreased, textures that are not visible are not loaded, and textures that are further away from the camera are loaded with lower resoltution. This option is only available in the Non-Interactve / Production Rendering Mode.

Texture Size – Specifies the resolution and bit depth to which the texture will be resized.

Bit Depth – Specifies the resolution and bit depth to which the texture will be resized.

 

Optimizations


This section of the Raytrace rollout is only available when set to Advanced Settings mode (). The parameters within the Optimizations settings change when Progressive is enabled or disabled.

 



Adaptive Lights – Number of lights from the scene that are evaluated by V-Ray when the Adaptive Lights option is enabled. To achieve a positive effect from probabilistic light sampling, this value must be lower than the actual number of lights in the scene.  Lower values make the rendering go faster, but the result is potentially more noisy. Higher values cause more lights to be computed at each hit point, thus producing less noise but increasing render times. 

When enabled, V-Ray chooses at random the specified number of lights and evaluates only those for the rendering, thus speeding up render time.  This option can introduce a visible degree of additional noise, but it makes it possible to render images that would otherwise take a very long time.

Max Trace Depth – Specifies the level to which all bounces that will be computed for reflections and refractions are clamped.

Max Ray Intensity – Specifies the level to which all secondary rays are clamped.

Opacity Depth – Controls to what depth transparent objects will be traced.

Secondary Ray Bias – A small positive offset that will be applied to all secondary rays; this can be used if you have overlapping faces in the scene to avoid the black splotches that may appear.

Subpixel Clamp – Specifies the level at which color components will be clamped.

Highlight Burn – Selectively applies exposure corrections to highlights in the image. Note that changing the value leads to render elements that can't be composited together to produce the RGB/Beauty image. This is the reason why we recommend that the parameter is set to 1. The Highlight Burn parameter in the VFB can be used for non-destructive color edits instead. 

 

System


This section of the Raytrace rollout is only available when set to Advanced Settings mode ().




Embree – Enables the Intel Embree raycaster. Note: The Embree raycaster derives its speed from the usage of single-precision floating point numbers, whereas the standard V-Ray raycaster selectively uses double precision. This lower precision of Embree may lead to artifacts in some scenes with very large extents.

Conserve Memory – Embree will use a more compact method for storing triangles, which might bed slightly slower but reduces memory usage.