What is the technical reason that the density field mode Colours isn’t supported in the Field Cache node, as is stated in the manual?
We would like to render a scene starting from 30 seconds instead of 0 seconds, and are unable to do so as we cannot create a cache in Colours mode.
The Field Cache uses a high-compression codec which so far has only been designed to support densities/densities and temperatures modes. We may add colour support in future.
For now, you’ll have to adapt the current system to use of those, or
render the scene with a 30 second preroll, and edit it out after the fact.