"Scalar Volume + Realtime applied transferfunctions" rendering allows dynamic changes on the transferfunction, but has ugly interpolation artifacts (the "interpolation before or after apply transferfunction"-issue).

One method to adress the issue, is to apply a static transferfunction and convert the scalar volume to an RGBA-volume.

This allows also compositing of multiple RGBA images,
allowing to show multiple organs simultaneously.

Currently the GPU volume render already supports RGBA images,
but not the 2D-Mappers nor the Software-Renderer.