Volume Object

Volume objects are created, for example, when you:

make a Volume Builder or a Volume Set editable.
detach selected components of a volume in the list of the Volume Set object via its Detach button.
import a *.vdb file.

Each Volume object represents a set of OpenVDB or voxel grids with linked, external *.vdb file (which may not be created until the scene is saved). Volume objects can be used for meshing or the definition of Initial States of a Pyro simulation, among other things. You will find examples of this in the description of the Volume Set object and in the explanation of the Pyro Scene parameters on the Pyro Output object.

Note:By the way, you can find out about the Voxel Size of the imported volume by taking a look at the Scale values in the Coordinates tab. This can be quite handy if you in group the Volume object to a Volume Builder and that uses the same Voxel Size. This can speed up processing because there is no need to resample (if both Voxel grids are congruent).