Unroll surface glitch - Rhino says its unrolling a surface ok, but where is it?


#1

hi there. I am new to this forum and only have been using Rhino for a week or two.

I am trying to unroll a surface. when I use the unroll command, Rhino appears to unroll it ok. at least it thinks its ok as it says: ‘4 surfaces unrolled’. However, no 2d geometry shows up anywhere in my file as far as I can tell.

all layers are on and visible and no objects are hidden. and if I create and unroll a simple box in the same file, it unrolls ok, so presumably its my surface that is the problem, not the Rhino settings… but i don’t know what it is that Rhino doesn’t like about it, so don’t know how to proceed.

any one have any experience of this scenario ? and/or knowledge of what I can do to fix??

thanks v much

unroll_prob_pascal.3dm (77.8 KB)


(Pascal Golay) #2

Hi Jack - the results will be at the World origin - are your inputs way off in the distance someplace?

-Pascal


(David Cockey) #3

Also on the World XY plane.


#4

hi pascal & david, i cant see anything at the xy origin. and if i check zoom extents can see nothing elsewhere either…


(Pascal Golay) #5

Hi Jack - can you send me or post the input surfaces?

thanks,

-Pascal


#6

Hi Jack, try ‘SelLast’ then ‘Zoom Selected’ straight after unrolling and you should see if the result is present.


#7

brian, thanks for the suggestion. unfortunately, ‘sel last’ highlights the surface i selected to unroll, not any new result


#8

yes, thanks Pascal. i just added the file to my post


(Pascal Golay) #9

Hm Command line reports

“Area is 874948.7533 sq millimeters (5807.87 % ) bigger after unrolling”

Trying one by one.
Oh. It’s all one kinky surface- this will not work - hold on…

So, with DivideAlongCreases to split the surface into the four surfaces (How was it made?), some of these unroll and one at least does not. I would split off the pointy ends of these and unroll them - use Split >Isocurve to split off the very tips of the surfaces. ShrinkTrimmedSrf the large part and UnrollSrf these. Basically, it does not like the singularities at the ends (UV compressed to a point).

unroll_prob_pascal_PG.3dm (207.4 KB)

-Pascal


#10

@pascal thankyou very much for looking and solving¬! mystery solved. i’ll follow your instructions.