I imported a .dxf model in MED via Import FBX,dxf.... While the mesh is imported correctly and can be textured, the engine preview does not show the model, but a black screen only.
After saving the model as a MDL7 file and reloading, the model can be displayed correctly in the engine preview.

Well, just a minor flaw, but people should know about it.

GSTUDIO A8, Extra edition, MED version 6.922
DXF file was created by Blobsculptor for DOS running in DOSBOX on WinXP SP3. Geforce 6200 512 MB, driver 6.14.0012.8558 from 8.10.2011.

NeoDumont