How to unroll a surface?

why does the command “Unroll Srf” affect the numbers of degrees. I have the problem to get 1 degree in V direction when i m using the unroll command and so the edges in one direction is totally strait. How i can control this effect. and in fact its not the same surface (same area size) at all. Why is that and what im doing wrong?

Can you post the Rhino file with the surface?

unrolling_08.3dm (71.7 KB)

in fact i want to have the same degree like the origin surface.

Hi alxwu- use UnrollSrfUV to maintain U and V directions and parameterization… not degree though.


UnrollSrfUV is not working too. you showed me the workaround with trimmed edges. is there another solutions ? any one?

Right now, I would say that making the trimmed surface is the only way to get an accurate unroll from that shape.