Just a quick note, I have seen frustum written frustRum, with an ‘r’. Both spelling seem to exist in the industry, so I wanted to know if it’s a mistake or not.
From the Wikipedia Frustum entry : “The spelling frustrum, listed as “erroneous” by the Oxford English Dictionary, is frequently encountered and might be considered a variant.”
Moreover Google returns 48 900 hits for FrustRum and 307 000 for Frustum.
So I’ll stick with the ‘Frustum’ spelling 😉