Specified Booleans
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To make holes in complex geometry, it is sometimes necessary to use bones that cut using boolean operations. Boolean operations require special attention because they utilize the raytracer, and hence are only visible when rendered. (Also, boolean operations are not considered for z-buffer shadows or post effects like volumetrics). The rules for boolean operations are strict: the boolean cutter bone geometry AND the geometry to be cut MUST be closed surfaces (a sphere for example). To use a bone as a Boolean, build the cutting geometry, assign the control points to a bone, and select the “Boolean Cutter” option on the bone’s Properties dialog. When rendered, the cutter bone’s geometry will subtract from the model’s other geometry, EXCEPT for geometry associated with bones that are children of the cutter bone, (in this way you can define parts of the model that lie inside the cutter but are to be left intact).
The first image above shows the three pieces of geometry with none of them acting as a Boolean cutter. The second image shows the green geometry cutting the other two pieces, and the third image shows the green geometry only cutting the pink base. This was accomplished by making the bone associated to the blue geometry a child of the bone that is associated with the green geometry.