11 CREATE THE VOLUME
The volume is created using a Collision Source geometry node. You can see how to set it up at 01:02:15. Checking Output Volume in the Display tab of the Parameter Editor converts the geometry to a VDB Signed Distance volume. You can change its resolution via the Voxel Size setting. A high value makes the simulation quicker to calculate; a low value makes it more accurate. I usually go with a value of 0.1 or 0.2. Cache the result out and give it an attribute you can reference, as shown at 01:03:00.