The Unseen University - Observatory Tower

  • I have been following Thomas's construction thread for the "Unseen University" with great interest, as well as some other threads on different forums. In photos of the Observatory, I have noticed a dark helical stripe up the side of the tower, which has seemed a little odd (but then on Discworld everything is a bit odd!) Now I have come to it in my own construction, I see that the stripe is the printed representation of an external staircase. This seems to me something of a shame, as in other parts of the model the 3D shape is well represented.


    I have decided to try to model the staircase fully, so here is the story of my attempt. The strategy will be to have an inner cylinder to form the inner wall of the stairs, fix a helical staircase and "ceiling" to it, then wrap round an outer skin. This outer skin will be coloured and textured using a scan of the original skin, so needs to match its shape. The inner skin is essentially the same but reduced in width. For the ceiling I should like to have a smooth ruled surface between the walls, but this is not developable to a flat sheet, so I shall use more steps, with a narrow smooth edging which can probably be stretched into a helical shape.


    Alan

  • Hi Alan!


    After finishing the stairs for the Observatory Tower - would you mind constructing the same for the Tower of Arts? :D


    It's only "slightly" more work....


    Will you share your construction afterwards? Maybe I'm going to add this to my construction (if you won't mind)


    greetings, thomas

  • Hi Alan,



    great idea!


    I have the UU at home and Thoma´s report greatly increased my desire to build it.
    Yours will be a most welcome addition, the staircase struck me too as somewhat below par for that great kit.



    Cheers


    Zaphod

  • Firstly, I meant to include a photo of the tower as it comes in the book, so that people who do not have it can see what I am talking about.


    Thomas - the (supposedly) 8888 steps of the Tower of Art are sadly hidden inside. Otherwise I am sure that they would be good for honing my construction skills! I do intend to have a go at showing the last few visible as they emerge at the top, though.


    If the whole thing turns out to be buildable, I shall be very happy to make the outline patterns available for anyone else crazy enough to try it. Since I intend to paint the stonework using scans from the book, though, I shall have to ask permission from the copyright holders to make the coloured version available. I will try.


    Now for the test build. The central column is rather long and narrow to get really smooth, so I shall probably make it in two sections in the end. It is good enough for a test, though. The steps went on quite easily, though slowly. I found that I could only do three or four at a time before letting the glue dry thoroughly.


    More soon.


    Alan

  • Lots more steps for the ceiling (53 to add to the 56 steps proper). I also added a central former for the outer skin. Top and bottom formers will go in after the skin is fitted. (Photo 1)


    I am afraid I got so excited putting on the outer skin that I forgot to take any photographs until it was finished. It was all rather easier than I had anticipated, though access was a bit difficult at times. The time spent ensuring that all the shape calculations were accurate paid off in the lack of any fit problems. (Photo 2)


    On the other hand, I got the shape of the ceiling edging wrong - I divided the tower radius by the cosine of the helix angle instead of the cosine squared. That fixed, the edging went on easily enough. (Photo 3)


    Now for a session (or two, or three) with GIMP to paint all the parts.


    Alan

  • As expected, that took longer than expected (!) I am still learning how to use GIMP, so do not always use the best techniques first time.


    The main piece is just the original artwork, except that I thought that the edge above the stairway should have a sloping band of stones. This was a row from elsewhere on the wall, repeated a few times. The same row, inverted and then cut up into separate stones and rearranged in a circle, served for the strip which will finish off that edge, so the joins between stones will line up.


    The interior stonework came from the Tower of Art, reduced in size. The steps are from the entrance to the Tower of Art, too, cut into individual steps and arranged around the circles (and repeated LOTS of times).


    Part way up the outer wall, between the main stairway cutouts, there is an opening showing some internal wall and the start of some steps. I have added this opening to the original design.


    As to construction, I have the internal wall, the top half of the steps and the interior of this extra opening installed. More soon.


    Alan

  • I had another problem with the helical edging strip. I had forgotten to allow for the thickness of the outer wall, so the strip turned out to be 1% too long. No real problem in itself, but it meant that the joints between the stones did not line up properly. So, strip it off and print a new one 1% smaller. Success!


    Finally, a picture of the old and new together, and the finished Observatory. I think it looks better, but then I am biased.


    Alan

  • hi alan!


    fantastic work - why couldn't you come up with that a little bit earlier... *sigh*



    just jokin' - if I ever build the UU again, I will do the observatory tower the same was - jokin' again. :D


    regards, thomas