How convert .mdl format?
Can you provide some information on what the model is, and what it comes from?
Looking online suggests that an MDL file is a Half-Life Model Image.
This makes me think maybe it contains 2D texture maps.
But, the file header mentions PLY, so maybe it contains something 3D.
What should the file contain? At only 1 MB it is pretty small, so it may be very simple geometry, or of low resolution.