This page provides information about the Frame Info tab of the V-Ray Volumetric Grid.
The Frame Info tab allows you to quickly check the size, dimensions, and contents of the loaded cache file for the current frame.
Container Dimensions - if a file is successfully loaded, shows the size of the bounding box of the cached contents for the current frame, in scene units. Prints [No Frame Loaded] otherwise. This parameter ignores any transformations (such as Scaling) applied to the transform node.
Info Box - if a file is successfully loaded, displays information regarding the channels present in the cache for the current frame. The container's size, as well as the total number of cells/voxels, is printed at the top. For each individual channel (such as Velocity, or Smoke), a single line consisting of the name and Min / Max range for that channel is also displayed.
The Info Box will only display channels which are remapped to the internal VolumeGrid channels using the 3rd Party Channels Mapping drop-downs in the Input tab.
For example, if your cache files contain a channel called my_test_channel which you intend to use as Smoke, forgetting to remap my_test_channel to Smoke in the Input tab will result in my_test_channel not being shown in the Info Box.
This is intentional, and the reason is optimization - loading and calculating the range of a channel can be time-consuming, especially with large datasets. If the channel is not used (ie. remapped to something), it won't be considered by the Frame Info Box.