SDFs as volume primitives can live in
.bgeofiles. They show up in the viewport as sort of inverted because the default fog makes the outside areas opaque. However, you can use the Primitive SOP to set their visualization to Iso Surface.
.simstores a bunch of simulation objects and their attached data.
.simdataonly stores the data attached to some simulation object.
You can create SDFs in
.simformat and save them as
.simdata. It is a mostly DOP specific format, but the File SOP will read
The Isooffset SOP only saves
.simdatafiles. The File DOP saves
.simfiles. The File Data DOP saves
.simdatafiles. The Explicit Cache option on the DOP Network saves
.simfiles. The Dynamics output driver saves
.sim. The File SOP will read
There is the Dynamics ROP to create
To turn an SDF into a
.sim, Volume Sample it in an Isooffset SOP and use the write mode. This will create a
.simdata, suitable for use by the RBD Collision cache.