[Diderick A. den Bakker]

On multiple curvatures and optical illusion. How did Tintin’s lunar rocket get in here?

A few remarks from designer Cor van Haasteren made me realise I should have said something about this in step 3, April 21.

We all know that paper curves beautifully in one direction, but not in two: it does not stretch, and will tear if you try this. Tintin’s rocket has a beautiful fluent curve horizontally (in other words, it is perfectly round on any level of the fuselage), but paper does not allow an extra fluent curve vertically.

# 4, 5, 6, 7: Fortunately our eyes (and the corresponding part of our brains) are easily cheated – we see what we expect to see, and it takes some closer scrutiny to notice the difference. (Nice off-topic example: which do you see first in # 4, the young girl, or the old woman? Be quiet, Freud! Now blink and you will see the other woman).

Back to Tintin. Everyone knows that the spaceship has a lovely fluent line – at first sight no one sees that the fuselage actually consists of a number of straight sided segments. You have to enlarge it quite a bit to make this visible (download it, then open it in Photoshop or similar). The picture of the nacelle shows that the more segments the designer makes, the better the impression of a really fluent line. The third picture is just another example – the cupola consists of a number of narrow ‘leaves’, each of them flat. The more leaves the better the final impression. To a computer designer, a ball consists of umpteen orange wedges.

In other words: one of two curves always consist of a number of straight lines.

Now back tot he first two pictures in Step 3:
# 1 and # 2: In # 2, Cor has converted the pen-and-paper drawing to a digital file. It sounds so simple, but is actually a whole lot of work. In his own words: ‘I used Illustrator to change the original drawings into a digital file, making use of all other sources such as other drawings and photographs’. Look closely, and you will see the suggestion of uninterrupted curves, whereas in reality, every segment is a sort of little box with straight sides, and the fuselage consists of a number of such 'boxes'.

Checking and comparing all measurements in different scale drawings – just imagine the patience and time this requires.

More in the next instalment.

PS: the Tintin model was designed by Jason Sutton. Contact me if you are interested.
For more pictures, go to papermodelsinternational.tumblr.com/, look for science fiction/