Currently we use a workarround to render dose color wash and iso lines. Iso lines are rendered by a helper node (child of the dose node) that uses a special mapper. The dose color wash is rendered by using the normal VTK mapper and an appropriate transfer function.

One reason was to not clone the normal VTK mapper and add special iso line code (first test implementation), because we than must mantaine the vtk mapping code twice.

The downside is that we no need the construct of the helper node.

It would be favorable, if we find a solution that combines both aspects:

• no unnecessary duplication of mapper code
• only on node to render everything