The namespace contains underlay definition objects.

### Classes
| Class | Description |
| :- | :- |
| [`CadDgnDefinition`](/cad/python-net/aspose.cad.fileformats.cad.cadobjects.underlaydefinition/caddgndefinition) | Class describing CadDgnDefinition |
| [`CadDwfDefinition`](/cad/python-net/aspose.cad.fileformats.cad.cadobjects.underlaydefinition/caddwfdefinition) | Class describing CadDwfDefinition |
| [`CadPdfDefinition`](/cad/python-net/aspose.cad.fileformats.cad.cadobjects.underlaydefinition/cadpdfdefinition) | Class describing CadPdfDefinition |
| [`CadUnderlayDefinition`](/cad/python-net/aspose.cad.fileformats.cad.cadobjects.underlaydefinition/cadunderlaydefinition) | Class describing UNDERLAYDEFINITION object. |