Doc:2.6/Manual/Physics/Fluid/volume init

Volume initialization type

• Volume will initialize the inner part of the object as fluid. This works only for closed objects.
• Shell will initialize only a thin layer for all faces of the mesh. This also works for non closed meshes.
• Both combines volume and shell - the mesh should also be closed. See the picture below.

Example of the different volume init types: Volume, Shell and Both (the shell is usually slightly larger than the inner volume)