I'm newbie
This is not possible, but you could use a workaround: You disable collision checking and then make a 'Clip'-Brush in the size you want your boundingbox. You can make a 'Clip'-Brush like any norma brush - insert it and then on the BrushAttributes You select 'Clip' for the Brush type.
Everyone can see the difficult, but only the wise can see the simple.
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