Automated unrollsrf command

I am attempting to use a vb component posted by Marc Hoppermann some time ago which uses a vbscript to call in the rhino unrollsrf command. The problem I am having is that the vb in its current state does not include the option to select curves or points on the surface to unroll as a guide (something the rhino command does).

I have made some attempts at modifying the vbscript but i honestly don't really know how to do it. See the discussion that I have had on another GH page here http://www.grasshopper3d.com/forum/topics/when-comes-the-unrollsrf

I anyone can take a look at this and solve it for me it would be amazing. I basically need to unroll a surface using its centroid a a reference point to the realign the unrolled surface around a common point. Some of the surfaces have a slight double curvature which I understand will distort the unrolled surface but in this case it is acceptable. The unroll curve or point is the crucial part.

Thanks

Leon

Attachments:

messing about with the vb unroll.ghx, 345 KB

Replies to This Discussion

Permalink Reply by Jacek Jaskólski on August 20, 2010 at 3:50am

Do you need to achieve this solely inside the vb component?

If not, you could try remapping your geometry from one surface to another:
- divide the base curve
- get the uv coordinates of the sample point by using ClosestPt on the base surface
- evaluate the unrolled surface at those coordinates
- interpolate curve

It's probably good to reparametrize both surfaces first just in case.

Does this work for you?

Permalink Reply by leon on August 20, 2010 at 4:05am

Hi Jacek,

Wow. Thanks alot.

I don't know why that hadn't occurred to me but its been giving me a headache for a while. The problem was that analyzing the area centroid after unrolling gives a different location to doing it first and then unrolling the point as part of the command (this is possibly in part due to the closest point command changing the location).

Anyway your solution is perfect and gives me a straight forward way of locating the 2 surfaces around a common point.

Thanks again

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