Depending on the version of AutoCAD or other product converting materials need to be considered.
New materials with procedural settings created in AutoCAD 2008 will not be convertible to previous versions of AutoCAD, except for the materials with procedural maps Marble and Wood. Marble and Wood existed in AutoCAD 2007 and will convert properly. Procedural maps that existed in AutoCAD 2007 (Marble and Wood) are convertible from AutoCAD 2008 to AutoCAD 2007. When opening a drawing with the new procedural maps offered in AutoCAD 2008 with AutoCAD 2007, the objects will appear with the AutoCAD 2008 material applied, but with default AutoCAD 2007 property settings in the Material window. If no changes are made to the material in AutoCAD 2007, then the material information will round trip back into AutoCAD 2008 with the original AutoCAD 2008 material properties settings.
There is a conversion process required for drawings prior to AutoCAD 2007. A system variable can be used to automatically convert drawings with materials from previous versions to the AutoCAD 2007 and AutoCAD 2008 materials format. The system variable is . There are three settings. If the variable is set to 0, no conversion will take place. If it is set to a value of 1, the default value, the conversion will take place automatically. If the value is set to 2, then the user will be prompted when materials need to be converted and will have the option to convert or not to convert.
If the system variable 3DCONVERSIONMODE is set to 0, no automatic conversion will take place. The command can be used to convert the old materials manually.