We have some interests to make volume rendering of volume bound to a non-linear transform. We know that, for now, Slicer does not handle this case.
Do you know if this feature has been asked in the past? Is there a will to make slicer compatible ? It is in VTK that the job must be done ?
You need to harden the non-linear transform on the volume if you want to display it using volume rendering. This is not a VTK limitation, we just have not yet implemented automatic resampling in the volume rendering displayable manager. It would be great if you could work on it. It would be very similar to what is implemented in the model displayable manager.