From GMod Wiki
This page shows the options available when you click on the Options tab in the Game Menu.
- Player Settings
- You can set your model, website, and various other things.
- Performance Settings
- Allows you to adjust extra graphical settings,
- Max Decals is the total allowed amount displayed on the screen at one time. Eg, blood, paint and bullet holes.
- Model LOD stands for "Level Of Detail" if this is set to -1 all models will be at their max detail level at any distance. If set to 5 the exact opposite happens.
- Shadows toggles whether shadows are cast by objects.
- Visual Settings
- Sets many different visual settings to do with tools.