Just in case you were wondering how to add new material presets to the Preset Manager, because I was and I spent a bunch of time trying…
The Preset Manager won’t pick up presets from anywhere else but the factory location (%XSI_HOME%\Data\DSPresets\Materials).
At first I thought I was doing something wrong. Then I used Process Manager to confirm that Softimage wasn’t loading presets from my User location. Then I checked for old bug reports/feature requests, and I double-checked the actual code for the preset manager.
There’s an environment variable XSI_DSPRESETS that specifies the location of the material presets, but you cannot use it to override the factory location. Even if you change that environment variable, Softimage reads only the factory Data\DSPresets\Materials folder.