Best way to model paper polyhedra?

[Scoox]

I would like to make a jagged face mask out of card, what is essentially an irregular polyhedron. Here's an example:

I don't know where or how I should start. I would appreciate it if someone could point me in the right direction. At this point I'm just trying to figure out what's the best tool for this job.

First thing that comes to mind is the sculpt environment, but when I drag edges, faces that originally were flat go all curvy and I would like all faces to remain flat.

Last, I would need to split the faces, add flanges or tabs so I can glue them together and and flatten then design (similar to flatten in the sheet environment).

Thanks 🙂

[jeff_strater]

to just create the model as shown, I would use 3D sketch lines, all connected, in one sketch, and use Boundary Patch to create the planar faces, then thicken to make it solid.  However, that won't get you the ability to unfold it.  You could try using Sheet Metal to create the folded structure (one Flange for each facet), but that will be a lot more work.  Theoretically, it should unfold, if you set it up right.

[Scoox]

Thanks @jeff_strater, I'll definitely give that a go, though I've not had much success with 3D sketches in the past (coincident lines disconnecting themselves).

[Scoox]

I tried but when I drag 3D sketch points other lines and points get moved around as well, so it's impossible to create a mesh I can manually sculpt. I think I need something like Blender.

[jeff_strater]

@Scoox, I have no doubt that there are better ways to do this, including maybe Blender (never used it, so I can't say).  But, you can do this in Fusion using sketch geometry and Boundary Patch.  I would probably start with a 2D sketch, simply because 2D is more convenient.  Construct a series of triangles using line.  The key here is to look for the square inference when constructing each line:

this indicates that you are connecting to an existing point.  That assures that your sketch will stay together when those points are moved.  Once you have the triangles laid out, you can use Move to move them off the sketch plane.  Make sure you select Sketch Objects in Move, and that you click on the points to move.  Since this is a symmetric object, I would only model half of it, and mirror it at the end.  So, you have to make sure that the boundary of the model stays on that sketch plane, so you have a clean plane to mirror it.

It will be a lot of work, but this is how I'd go about it in Fusion.

Screencast will be displayed here after you click Post.

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[TrippyLighting]

The difficulty in this mode is to keep the polygons with more than 3 vertices flat. If the whole object would be made from triangles only this would not be a problem, because triangles are by definition flat.

There is some special software designed to solve exactly this sort of problem space Pepakura Designer

[Scoox]

@TrippyLighting Pepakura came up while Googling this. From the software's website:

Note that Pepakura Designer does not have 3D data design features.
You require 3D data before starting to use Pepakura Designer. Pepakura Designer supports common 3DCG file formats.

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Perakura takes a 3D model and flattens it so you can make it out of paper. This is basically what I want but it means I'd still need to create the actual 3D model somewhere else.

I would have thought Fusion's sculpt would have been able to do this—the concept is not too far off—but straight lines and faces go curve the moment you move them.

[TrippyLighting]

You CAN do this in the sculpt environment and simply make sure you model this in box view mode.

When completely done with the model - I cannot stress this enough, you have to be completely done, perhaps only very minor adjustments - then crease all edges and then after conversion it will retain the polygonal look.

If it should fail to convert, then simply while in the sculpt work space export the control cage into a ,obj file.
Re-import this and convert it directly into a BRep.