Unroll polysurfaces

I am trying to unroll the attached surfaces and Rhino is not liking them, the items were imported from a solid works model, so they are not native to rhino. Any ideas as to why it is not giving me a good unrolled piece?Surfaces.3dm (3.0 MB)

Hi Gretchen - these are made up of a lot of faces - converted from a polygon mesh no doubt - Looks like three of the four will unroll, albeit with issues, if Explode=No ,all OK with Explode=Yes, here. Is the goal to get all the little flattened or to get a simpler surface that unroll as one thing?

@gretchenb - is the attached what you’re after, more or less? These are not super accurate, but is that the idea?
Surfaces_maybe.3dm (96.4 KB)


I am wanting to get one large outline for sheet metal to be cut from. They are made up of lots of faces, all from the solid works file that I was sent. I have done this several times with items that I have created in Rhino or AutoCad, but this stl file is giving me issues. Nothing seems to work, unroll, smash, squish, none of them are giving me a smooth outline. We have one much more complicated things than this without any issues, but all from scratch, not starting from a 3D file. I can’t view your file at the moment, our IT guy is working on our zoo issue.

So, I opened your file and that is what I am wanting. How did you unroll them? I was trying to do it in 5.0, but it wasn’t giving me anything as clean as this one.

Hi Gretchen - I (quickly in this case, in order to ask the question only) made new surfaces from the long edges of the polysurfaces all chained together and Joined, followed by Rebuild and Loft on the pairs of curves - you can do that as well, just being careful to get the right shapes. In the cases where the short edges are not straight across as you’ll get from a loft, you might need to ExtendSrf and then trim back with the correct edge curve.


I was hoping to not have to do that, but I guess if that is the best method, I will take the time to do. We were hoping to not have to create anything and just use the solidworks model. Thanks for the help!

i am sure or highly believe they could provide you with single nurbs surfaces instead of polysurfaces. it looks to me that those were meshed at some point then turned into unnecessary polysurfaces. not the usual solidwork output i would say.

I just requested a better file, we shall see if I get one.

I ended up creating curves and surfaces, it will be close enough for what the sculptor needs for this one. Thanks to both of you for your input.