The intended method of erasing part of a wall component is to use the Edit Cut Profile tool (just to the left of the Demolish tool in the tool bar). To erase one bit of the wall component sketch two horizontal lines, and make sure that the arrow points toward the part you want to keep. To erase lots of repeating portions, while editing the sketch select the two horizontal lines and use Copy with Multiple checked. This isn't as convenient as the repeating detail solution, but it will correctly erase the parts of the wall you need erased while leaving the rest.Originally Posted by Martin P