UI for CAD-style apps is not that complex. You're typically looking at maybe hundreds of visible controls at most. Of course, assuming that the rendering of the picture/parts is handled separately.

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fastball 5 hours ago | parent [-]

Hundreds of visible controls sounds like more complexity than you want.

	▲	Elucalidavah 4 hours ago \| parent [-]
		These controls are largely independent; whereas the complexity being talked about here is interdependent GUI elements. Something about every complex GUI being a spreadsheet-style calculation.