This type of volumetrics can currently load an OpenVDB file (.vdb). This file format can efficiently store very detailed and large volumetrics based on a 3D grid of voxels, instead of individual particles, which makes it more efficient for storing and rendering detailed volumetrics.
pending screenshot of main parameters (the VDB source axis and Base multiplier need to be moved to the top of the UI)
Once you've set the "Field type" parameter to "Volume file based" you can load an .vdb file in the filename parameter. Please note that the "Field Density" parameter has no influence when using OpenVDB files.
Parameters
- Base Grid: set the name of the base grid inside the VDB file that defines the volumetric domain. Usually this field is called "density". If no name is supplied here, Maxwell uses the first grid present in the file.
- Base Grid density: controls the density of the base grid.
- Additional grids for UV: here you can specify names of other grids usually found in VDB file that describe velocity or temperature, or any other data that was calculated during a simulation (such as particle distance, acceleration etc.). These grids can be used to map textures, usually a colored gradient, to better visualize the stored data. For example if the VDB file contains a "temperature" field, this means that the different temperatures of the simulation is stored in the file and you can use it to visualize these different temperatures using a blue to red gradient that uses this field as a driver to create the necessary UV map when rendering. Please see the "Texturing OpenVDB volumetrics" below for more details.