Engine – Switches between the CPU, GPU or RTX rendering modes of V-Ray.

Sampler – Specifies the image sampler type. Specific parameters for the selected type appear below.

Bucket – Takes a variable number of samples per pixel depending on the difference in the intensity of the pixels.
Progressive – Progressively samples the entire image.

GI – Enables indirect illumination for baking.

Shadows – Enables shadows for baking.

Disable Lightning – Disables all lights in the scene during baking, even the default ones if there are no other lights. When the option is enabled, only self-illuminating materials emit light.

Progressive Sampler Settings

Available when Sampler is set to Progressive.

Noise Threshold – Controls the desired noise level in the image.

Render Time (min) – Controls the maximum render time in minutes. This is the render time for the final pixels only; it does not include any GI prepasses like light cache, irradiance map etc. The default value of 0.0 means that the render is not limited in time.

Bucket Sampler Settings

Available when Sampler is set to Bucket.

Noise Threshold – Controls the desired noise level in the image.

Max Subdivs – Determines the maximum number of samples for a pixel. The actual maximum number of samples is the square of this number (e.g. 4 subdivs produces a maximum of 16 samples).

Progressive Sampler Settings

Bucket Sampler Settings

Subdivs – Determines how many paths are traced from the camera. The actual number of paths is the square of the subdivs.

Sample Size – Determines the spacing of the samples in the light cache.

Enable Caustics – Enables caustics computation.

Multiplier – Controls the strength of the caustics. It is global and applies to all light sources that generate caustics. If you want different multipliers for the different light sources, use local light settings. 

Search Distance – Specifies search distance for caustics photons.

Max Photons – Specifies the maximum number of photons within the search area circle that are considered when rendering the caustics effect on a surface. Smaller values cause less photons to be used and the caustics are sharper, but perhaps noisier. Larger values produce smoother but blurrier caustics. If the value is 0, V-Ray uses all the photons that it can find inside the search area (Search Distance). 

Max Density – Limits the resolution (and thus the memory) of the caustics photon map. Whenever V-Ray needs to store a new photon in the caustics photon map, it first looks if there are any other photons within a distance specified by Max Density. If there is already a suitable photon in the map, V-Ray just adds the energy of the new photon to the one in the map. Otherwise, V-Ray stores the new photon in the photon map. Using this options allows you to shoot many photons (and thus get smoother results) while keeping the size of the caustics photon map manageable.

RGB Color Space – Specifies the type of color mapping.

Go To Rop Node – Opens the lights settings of the Renderer ROP.

Enabled – Enables denoising for texture baking, provided the V-Ray Denoiser render element is present. Note that the Default V-Ray Denoiser is always used here.

Preset – When using the Default V-Ray Denoiser, the presets can be used to automatically set the Strength and Radius values.

Default – Applies a mid-level denoising.
Mild – Applies a more subtle level of denoising than the Default preset.
Strong – Applies a stronger level of denoising than the Default preset.
Custom – Allows the Strength and Radius parameters to be set to custom values.

Radius – Specifies the area around each pixel to be sampled for determining how to denoise a given pixel. Larger values produce smoother results, but slow down the denoiser.

Strength – Determines how strong the denoising operation is. Larger values remove noise more aggressively, but may blur the image too much.

Mode – Specifies how the results of the Denoiser are saved.

None – All render elements required for denoising are generated so that denoising can be done with the Standalone Denoise Tool. The information calculated within them is not applied to other render elements, and no DenoiserRender Element is generated.
Replace RGB – The RGB Color Render Element is replaced with the denoised version, and the DenoiserRender Element is not present as a separate channel.
Separate Channel – The DenoiserRender Element is generated to contain a denoised version of the RGB Color Render Element using the specified settings. The original render elements, including the RGB Color Render Element, are not changed.

Use GPU – Uses the GPU device(s) to accelerate the denoising calculations. In case there is no compatible GPU device, denoising automatically falls back to use the CPU, even if the option is enabled.

Forced Attributes – Specifies a list of attributes to be exported to the .vrscene file even if they are not used by any V-Ray shading node. This optimizes the export speed and reduces the size of the .vrscene file. Forced Attributes parameter is useful when instancing lights with per-point attributes for light color and light intensity.

Forced Materials – Specifies a list of materials to be exported to the .vrscene file even if they are not used by any V-Ray shading node. For example, if there is an Alembic file with a material path attribute pointing to /mat/customAlembicMaterial, V-Ray does not export the shading nodes unless they are assigned somewhere. Thus, even though the material is present in the scene, it is not picked up and the alembic file renders with default material instead of the /mat/customAlembicMaterial. Adding /mat/customAlembicMaterial to the Forced Materials list exports it. 

Candidate Objects – The geometry objects in this parameter are included in the rendering process if their display flags are turned on.

Use Lights – The lights in this parameter are added to the render regardless of their value in their display flags.

Use File – Enable to use a Python post-translate file.

File (*.py) – Adds a Python post-translate file.

Use Script – Enable to use a Python post-translate script.

Script (Python) – Adds a Python post-translate script.