Its common practice now with ZB4 to create panels and details, by masking then extracting. But this just gives straight edges to the extrusion.
The method in this video will help create shapes with complex bevelled edges.
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The gradient of the stroke controls the curve of the bevel. A simple black to white gradient would produce a 45 degree sloping edge, but by messing with the gradient you can produce interesting carving effects.
To create the object from the alpha follow the video tutorial below.
http://www.youtube.com/watch?v=56XsmXVH6fw
Any questions please just ask.
Zenith.