During a two hour train journey, I constructed the frame for the whole assembly of the scanner digitally in a piece of software called "Cinema 4D".
It took me quite some time to make the virtual model to become what is called "water-tight" *.
Finally we needed to find a way to turn the virtual CAD-model into an actual physical object.
It seemed that 3D-printing technology, which we already successfully used to build some smaller custom parts, was the way to go. However, the fact that the volume of the object in questions is the critical factor for the fabrication-costs lead us to dismiss the 3D-printing process.
(As it lies in the nature of a frame to occupy a huge geometrical volume even though it's empty on the inside, we ended in a price offer of more that 4500$)
Where do we go from here..?
* To give you a comprehensible example, think of you returning home from a holiday, carrying a souvenir model of one of the pyramids of Gizhe with you. The little souvenir-pyramid has about the size of the palm of your hand and is hollow, meaning it has no bottom covering part and only consists from the side-walls, but for a model this is - of course - perfectly ok.
You might want to place it on the book-shelf but it looks a bit lost there between the books that are slightly taller.
You come up with an idea: you will impose the pyramid over a paper coffee-cup like if it stood on a socle-mounting (the pyramid overlapps the cup a little bit).
The pyramid thrones now suitable on the very top of your shelf!
Yet, your work is not perfect - the pyramid sits very shaky and unstable on the round edge of the paper-cup, the circulating air that results from just opening a window will wave the pyramid from its base.
As you investigate the problem, you will find out, that in fact the inner walls of the pyramid make contact on just 4 single points of the paper-cup, because of the cylindric shape of the latter.
Now in terms of a virtual 3D computer graphics model in a figurative sense making our souvenir-pyramid water-tight would mean to cut the paper-cup into shape so any single point of the cups edge touches the pyramid, all around the full 360 degrees regardless of the two completely different shapes of a round cup and a square pyramid!
