Setting out a right angle triangle: both sides are about 3m. I would like to make it right angled as accurately as possible. The obvious way of doing this is to split a laser beam into 2 beams 90 deg apart by firing it into an accurately ground internally reflecting prism. Is there any such device on the market?
There's no requirement for levelling in this: just need a 'perfect' right angle. I've looked at a variety of laser levels and line drawers but none appear to do this, or at least fail to proclaim the facility on the packaging. Or any other suggestion?
TIA