mountains and valleys

Hello All,

Any ideas for how we could accurately test for the direction of paper folds, for example, when strips are unrolled, how might we change the color of diagonals so we know which is a mountain fold, and which is a valley fold?

This would be similar to Pepakura's output, but with more control I suppose ...

I realize the paper folding techniques have been somewhat exhausted on this forum, but I did a search and couldn't find anything related to this particular inquiry.

Very Best,

Tags: facets, folds, mountain, unroll, valley

Attachments:

UnrollStrip_v0804.ghx, 895 KB

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Permalink Reply by Chris Tietjen on August 25, 2011 at 3:30pm

You could look at the distance between the start points and end points of the normal vectors at the centroids on two adjacent panels. If the tips are closer together than the tails, your hinge line is a crease otherwise a ridge. Then to mark the crease draw a line between the two centroids and project the line to the surfaces.

Chris

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Permalink Reply by Nick Bruscia on August 26, 2011 at 12:41pm

Thanks Chris, this is a nice solution!

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Permalink Reply by taz on August 25, 2011 at 5:21pm

Finding the angle between faces can help...

See this concurrent discussion:

http://www.grasshopper3d.com/forum/topics/the-bisector-of-two-surfaces

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Permalink Reply by taz on August 25, 2011 at 5:49pm

Also check Daniels latest Kangaroo Origami example... it starts with colored mountain and valley curves.

http://www.grasshopper3d.com/profiles/blogs/kangaroo-updated-for-gr...

But this is the face angle concept for post processing...

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Permalink Reply by Nick Bruscia on August 26, 2011 at 12:43pm

I've started to do just that, and stopped for a moment to post here to get some other opinions. I hadn't gotten as far as the example(s) you posted below. Thanks for the help!

I'll also be sure to test drive the Kangaroo example - I was not aware of it until now.