In the Planmeca screenshot the skin surface is displayed using transparent surface-like rendering. There are several options for achieving this in Slicer.
There are two interesting things to note on the Planmeca screenshot:
- The skin surface and bones come from two completely different images. You can see this very clearly at the tip of the chin. Do you intentionally visualize skin surface from one image and bones from another?
- Skin, soft-tissues, and low-density bone are all aggressively suppressed, so it seems that Planmeca uses the technique shown in @pieper’s demo above (have a 0-opacity gap in the scalar opacity mapping to suppress soft tissues, while showing skin surface and bone)
Just to clarify, this rendering is already available in Slicer (what the demo shows is just a different way of editing transfer functions, so that you can move selected control points together, independently from the others). For example, reproducing the same two-peak scalar opacity transfer function using the current volume rendering module:
You can increase ambient lighting to make the edges of the skin surface better visible:
In addition to suppressing soft tissues using scalar opacity mapping, you can also suppress soft tissues using gradient opacity mapping (since there are no sudden intensity changes in soft tissues):
So, it seems that you can achieve skin surface + bone rendering with a single volume renderer. However, Slicer also offers many other options for suppressing soft tissues and displaying skin surface differently from bone (mask out soft tissue and use single-volume rendering; separate skin surface and bone using volume masking and render the two volumes independently using multi-volume rendering; or segment skin surface using thresholding, fill holes using Wrap Solidify effect, and render as a transparent model).