Hello, I’ve been having a little trouble with flattening an object accurately in Rhino. I’ve trying to create a physical model of a building proposal, and it needs to be almost completely accurate to form (I’m using museum board, scoring the back side to bend up via laser cutter). The problem is I can’t do an unroll surface on this object because of the double curves. I tried to use squish but it would distort this piece completely. What would be the best way to approach this?
i am not sure about the material you use, i assume its very ridgid and not well suited for something like that, additionally the shape is extremely tricky to “flatten”.. either way you should also explode the polysurface first and flatten only one surface not the entire compound. you can also use ExtractSrf with copy yes to just extract either the top or the lower surface,
what you then could try since all other methods indeed do not produce a good result is to use ProjectToCPlane on that extracted surface, make it a bit bigger to compensate for the stretch.
To clarify the material I’m using is rigid and is similar to a poster board (4 ply, about 1/16" thick), which makes it pretty difficult to do curved shapes.
Your method works but one thing I’m not sure about is if curvature for the inner bend is going to be preserved when I try to fold it up. Btw In this screenshot I scaled up the model to the length of its edge curve (the blue curve) then projected it on the cplane.
That shape has double curvature, which means you can’t make it starting with a single flat sheet without stretching/compressing/shearing the sheet. That is how geometry works.
It could be made from multiple strips bent and glued together.
As shown, it can’t be done. As you’ve noted, it has double curvature.
The only way to achieve this is to approximate the area that is doubly curved, which is the area in blue, below. Think about making it out of flat strips, either in orange direction or pink direction. Alternatively, it could be made in flat panels by combining the orange and pink direction cuts. Panelling Tools may come in handy here.
