About Conversion of Material Data
The material data in releases before Pro/ENGINEER Wildfire 3.0 is stored in mmatl.lib files or in files with the .mat extension.
You can convert a mmatl.lib file created in Creo Simulate before Pro/ENGINEER Wildfire 3.0 to .mtl files by clicking File > Convert pre-Wildfire 3.0 lib in the Materials dialog box. You can edit existing materials definitions, that is, the .mat files in Creo Parametric. These files are saved to the .mtl format when you save the material definition.
If the following parameters are present in existing material definitions, then Creo Parametric adds the new material as user-defined parameters.
Cost (in Creo Simulate)
Conversion of Material in the Model
Before editing a model that contains a material created in Creo Simulate before Pro/ENGINEER Wildfire 3.0 and if this material is a non-isotropic material or a material with functions, parameters, fatigue properties, or failure criteria, then you must convert material data in the model to the latest format. If you edit such a model or material in Creo Parametric without converting the material to the latest format, you may lose your data associated with the material.