Unfolding with Compound Transforms

2013 update: this is probably a better way to go.

Unroll%20Brep.gh

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Cross posted here.

UPDATED TO WORK WITH VERSION 0.8.0010

Lately, in some of my work I have been investigating unfolding complex forms with Grasshopper. The newest release of Grasshopper enables the use of Compound Transformations, which makes it possible to quite efficiently unfold strips of planar surfaces. In the past I have had to use pepakura or other similar utilities to perform the unfolding outside of Rhino, or alternately a slow faux-recursive method where I essentially unfold one segment of the polysurface at a time.  
Below are a few definitions making use of this new capability.

The first, here (unfold_surface_strips.ghx), simply takes a list of surfaces that adjoin each other at an edge and unfolds them flat.


The second (triangulated_surface_strip_tool.ghx) utilizes the same processes in the first to unfold a triangulated version of an input surface. Strips can be evaluated in the U or V direction.



Finally, with the right settings on the same definition (setting V divisions to 1 and U divisions to some high number) it can be used to substitute for the UnrollSrf command in Rhino with a high degree of accuracy. This is an improvement in efficiency and accuracy over my earlier Unroll definition.