There is a useful instrument I found on Ebay which can be used for measuring pyramid angles. After constructing a PVC pyramid I found the angles were not exact. This is due to sagging of the pipes especially if sand is added. Plumbing grade PVC pipes are available in Australia but not furniture grade pipe. Plumbing grade pipe is also more bendy. Plastic is not the best material for precision pyramids. Wood or bamboo may be a better choice.
Thanks for the note. You’re right about precision. Always strive for it because the end result can work its way out of desired end result. And woods are easier to precise cut than pvc. Yet it’s a lot lighter and can be move about.