Due to the way that the OpenVDB SOPs have been "verbified" for use in Houdini compile blocks, a parameter dependency is created for every parameter that exists on the nodes UI, irrespective of whether the parameter is in use. This usually isn't a big problem, but can manifest in some unexpected ways when parameters involve geometry or time dependant expressions. In the case of the latter, this forces nodes to be time dependant, re-cooking their inputs every timestep even if the parameters are not used.

Currently no SOP implement default parameter values which cause this (I think) and we should avoid such for the foreseeable future. But this can very easily catch people out if they use the same node to implement a time-dep expression ($F, $T etc) and later decide to switch settings which no longer require these values.

The most obvious solution is to transition to embedded .ds. This replaces the PRM_Template() of traditional HDK operators, and would replace the parms.add() methods of the current VDB SOPs. Instead, a C++ inline string is used for the actual DS file.