To make a mat file, select the object you have who's material properties you like. Click the M or Edit Materials.

Press the arrow nearest the upper right of the preview.

Press the Add button, give your material a name and description and press ok.

Then Press the Export button and save.

Go back, press the Print Screen button, and go into IrfanView ( http://www.irfanview.com/ ) or your favorite picture editing program, paste, and cut the preview out, and save that as jpg.

You will need this for the thumbnail portion of the upload.

Lastly goto the materials exchange category and upload your mat file and jpg thumbnail.[/b]

NOTE: The thumbnail you see there.. WILL NOT be the correct thumbnail, that is OK, it will adjust automatically later.

I noticed that the file extension has to be in upper case. "mymat.mat" won't upload, but "mymat.MAT" does. And this belongs to the picture part while the 96 x 96 pixel copy from the mat lab named "mymat.jpg" goes as thumbnail.