Once you import a garbage mask as a 3D geometry into Action, use the GMask menu to extrude the garbage mask.
Depth fieldExtrudes the garbage mask, making it three dimensional. Use the depth setting in conjunction with the Axis controls to manipulate the garbage mask.
Replace buttonApplies changes to the garbage mask geometry.
Bevel curveAdds a bevelled edge to your garbage mask geometry. Use the options in the Edit Mode box to add, select, delete, or move keyframes on the Bevel curve. The Bevel curve behaves in much the same way as an animation curve in the Channel Editor.
Home buttonResets the Bevel curve viewer to show the whole curve.
Undo buttonUndoes Bevel curve operations.
Reset buttonResets the Bevel curve.
See Working with 3D Geometry for definitions of the specific Geometry controls.
Click the Geometry tab to access the Geometry menu to apply any of the geometry settings to your garbage mask.