Is their any way a script can be created that works to unroll non compound surfaces. I do a lot of retail work where fixtures are created and an I need to work out a flat pattern for applying graphics to surfaces i.e. around bent shapes. I know Rhino can do this but it would be great in Moi. Just thought I'd ask...

I wonder what would happen if "Unwrap" script were applied to a bunch of isocurves?

Unroll would be great.

Here is a manual unroll of a catenary shaped surface, using unwrap script.
(Just messing around to see if there is a possibility of a script.)
Put an isocurve in the center. Unwrapped three curves. Drew two outer lines. Did Planar.
I think it would only work on certain surfaces, like rolled up paper... (?)

edit: well, the length of the sides is not right...
The two curved edges would remain a bit curved, when unrolled...
Have to call it the unwrolled script, with a w. :-)

Hi Matt, unrolling is a very substantial and complex operation, it's not really something that can be produced very easily just by a script.

Scripts are best at doing things by automating existing functions and gluing several operations together. A surface unroll is not much like that at all, it's more of a completely new function.

I don't think it's very feasible for me to do surface unrolling in MoI - there is one developer at Rhino that spends a lot of time just on that one feature alone. It's pretty difficult for me to undertake tasks that take a substantial amount of development time like that.

So for the foreseeable future I would recommend using Rhino to do that particular task, it is not likely to be something that I will be able to add into MoI in any near time frame.

There are various other complications with it as well - only certain kinds of surfaces ("Developable surfaces") can be precisely unrolled, not just any surface that you might create. Most surfaces that you construct with compound curvature in them cannot be unrolled to a flat pattern exactly, for example a sphere surface cannot be unrolled to a flat pattern without incorporating a whole lot of stretching and/or compressing of the material involved.

So really to do unrolling very well would not only involve the unrolling itself but also a bunch of other tools involving developable surfaces, stuff like analyzing whether a surface is developable or not, maybe some construction tools that limited themselves to only construct things that were straight in one direction and thus developable, etc... So taken all together that's a huge amount of work really.

You also might want to look at Lamina Design, it takes polygon mesh input and can do an unwrap of the mesh: http://laminadesign.com/

- Michael

Hi Brian,

> I wonder what would happen if "Unwrap" script were applied to a bunch of isocurves?

That will only work if the surface is a developable surface - basically the isocurves being targeted have to be lines.

- Michael

Thank you for all the information.
I was thinking about some sort of reverse lineweb. Take a grid of isocurves, flatten them, and connect the ends with curves.
or do some kind of (sort of reverse) flow. But it just is too complicated, or un-doable... :)

Thanks Michael,

I thought it might be too complex an ask. I have checked our Laminadesign and this is a perfect tool for my designers. I can just imagine the complex forms they will dream up now! That's for the tip.

>> I don't think it's very feasible for me to do surface unrolling in MoI - there is one developer at Rhino that spends a lot of time just on that one feature alone. It's pretty difficult for me to undertake tasks that take a substantial amount of development time like that.


Maybe you can ask this developer if he wants to help you, and offer this function as a plugin for MoI at his own income.

I think, there are a lot possibilities to use it.

I once had to make a big barrel for a stage and used Rhino to unroll the planks. It was not very exact, but good enough for the stage.

Hi Rudl,

> Maybe you can ask this developer if he wants to help you, and offer this
> function as a plugin for MoI at his own income.

The developer works at McNeel, not independently, so I don't think that this would be possible.

There are quite a few areas like this where there would be a significant amount of work involved where it's just not feasible for me to put it inside of MoI, so if another program does do what you need then it's natural to use that program in combination with MoI to get your final result.

- Michael

Here is an approximation unfold of a simple moi catenary loft, (posted above), which appears to be a ruled surface, and I think it is also developable. Developable surfaces are a subset of ruled surfaces. Spent a lot of time doing google scholar searches for developable surfaces and NURBS. It is a very difficult subject. Flattening is used for ship hulls, shoes, and garments. I did not find any way to directly convert NURBS to an unrolled state, with the possible exception of the Rhino Unroll surface command. (Maybe it uses hidden meshes?) Unrolling, or flattening, can be done by converting the NURBS surface into meshes. More difficult NURBS surfaces can sometimes be cut up into strips of mesh triangles, and the pieces flattened. Some NURBS surfaces would require "stretching" and be "distorted."

The original .3dm was exported as a sketchup .skp file.
Two sketchup plugins were used, with sketchup version 8.
One was Jims unfold plugin for sketchup. View hidden geometry was selected, and all of the triangular slices were selected in order, a bit tedious.
The other plugin was TIG's Object exporter for sketchup.
Michael's Obj to 3dm program was used to get the flat model back into Moi. The flat was very small compared to the original, with inch/metric problem. Ran a rebuild on the edges.
http://sketchucation.com/forums/viewtopic.php?f=323&t=33448

https://sites.google.com/site/jimfoltz/my-sketchup-plugins

Final result is an approximation.

Also found a stripification pdf/algorithm, which used two nurbs curves to create strips of triangles. (Back to mesh again.) It may be scriptable, for simple nurbs patches...

There are some cheap programs to make paper 3d models.