Extruding can be done on lines, curves, or faces. An extrusion is specified by a vector:
extrude <x> <y> <z> extrude <faceNum> <x> <y> <z>First draw a curve while in insert mode (hit the i key). Complete the curve by hitting right click, or enter.
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Then extrude the line.
extrude <x> <y> <z>
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Now turn on face numbers to determine which face to extrude.
view fnums
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Pick a face and specify the vector.
extrude <faceNum> <x> <y> <z>
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