Thursday, September 16, 2010

This One Rings a Bell (11)

Progress at last. That Bézier spline tool did the trick, allowing me to obtain accurately curved common rafters and irregular hip rafter. That advance in turn made possible the development of the roof surfaces and the curved parallelogram shaped jack rafters. Yes, those too are complicated!

Here's a view of the irregular hip corner, showing the situation:


I used the French method for off-centering the arris for the hip backing cut. This technique results in the same amount of wood left at the hip under each jack rafter mortise. The hip's length is provisional for the time being, and will probably be trimmed shorter. The hip does not extend all the way to the ridge, as this would mean that more of the commons would need to be divided around the hip. There will be a pair of flanking cantilevers which will serve to bear the loads in the area of the hip, and I will be drawing those shortly.

Here's a view from the inside, a view no observer of the completed tower will ever see:


I went on and produced the materials which lay atop the rafters, some 3/4" boarding and the peel and stick, etc, and was then able to obtain some views of the entire roof. Here's one view:


The lines present in the roof plane are simply abutments between planes in the sketch - in the actual roof there will be no lines there. The lines make it look like there are slight creases in the roof, which will not be the case in reality.

Bird's eye view - notice that the fact that the hips are irregular is not so obvious:


One of my favorite views of the irregular irimoya:


Sharp-eyed readers might note that the fukiji is a bit more pronounced in its swell than the picture from the previous posting- I discovered a drawing error from before which caused the old one to actually taper down slightly at it was supposed to be swelling. Dang! Redrawing that part, which curves up, curves in, and has a slight twist towards the end, took another three hours. I really hope I don't have to draw it again!

One more of the drawing, though it looks a little, um, lonely without the bell hanging in there:


I'll re-insert the bell in the final drawings, as it is very data-dense and slows down the rendering.

The copper tile paneling I found to paste on the roof doesn't really do justice to how the roof will look. Here's a glimpse of the sort of result I am seeking to obtain, but haven't been able to depict accurately in the drawing:


Nothing quite so sublime as copper shingles, except for bark shingles perhaps.

Okay, tomorrow I will re-establish the verge boards on the gable and their associated fascia. After that comes the ridge above the ridge and the oni-gawara, or 'ogre tiles'. Then I need to deal with the minoko, which given its complex curvilinear shape will be tough to draw I'm sure, and finally, last but not least, I can place the internal structural elements in the upper roof. Those wondering how it all goes together and works as a roof will have to wait until then to see how I configure those parts. For this point in time I'm relieved to have finally obtained the roof shape I was after. What a battle!

Thanks for coming by the Carpentry Way today. --> on to post 12

5 comments:

  1. Chris,

    This is fascinating stuff. I'm enjoying your posts immensely, thank you for doing this for all to see.

    Dan

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  2. Chris

    The photo with the copper shingles, is that the 'drooping verge' that you mentioned before? I have something similar on my house, but its just 85 years of gravity and a heavy barge rafter with no brackets.

    The new drawings look great. Can't wait to see more!

    Tom

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  3. Dan, thanks for that - glad you are enjoying the read.

    Tom, yes, the photo does show the minoko - one variety anyhow. it will be tricky to draw, and SketchUp lacks a feature to allow it to simulate the 85 years of sagging you mention...

    I'll be doing a post on minoko in more detail in the next few entries.

    ~Chris

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  4. Stumbled on your blog researching roof designs for a japanese inspired garden structure. Beautiful work!

    ReplyDelete
  5. Anon,

    thanks for your comment and kindly sentiment. Just a reminder: please append your name to any future comments (even when posting as 'anonymous')or I will delete them. The rules are stated clearly just below this section.


    ~Chris

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