Is your feature request related to a problem? Please describe.
F3D recently added support for displaying specific part of a scene, however not all format supports that yet.
Lets add it for MDL format

Describe the solution you'd like

• Read the QuakeMDL spec to identify how is a file split in parts
• Implement that split by creating multiple actors and a vtkDataAssembly describing the scene with correct labels
• Add tests