How to model cardboard thickness and crease in Rhino (for a cardboard object)

Hi!
I have to create a model of a cardboard object, and I don’t really know what would be the best strategy to model with fidelity the thickness and the creases.
The object is like a piece of origami and has many creases rather sharp. I started to draw panels with 6mm thickness, but when it comes to create the sharp bent or crease it gets complicated. I tried sweep to rail, and It gives some good results, except for sharp angles where the paper folded one onto the other…
Since the model is for producing a Hi-Def rendering…
If you have any idea on how to proceed, please kindly let me know.
Thank you
Cheers,

Hi David,

I’ve recently done a couple of cardboard engineering projects where I’ve had to emulate boxes and folded objects.

I found working with the flat net as a 2D surface which is split at the creases to be very helpful, this was for step by step IKEA type guides.

Where I’ve modelled things for product shots I’ve measured the boxes when fully made up and then added a thickness, then added fillets. The trick to stop them looking like extruded boxes is to add the curves to the surfaces, you’ll notice that the boxes are slightly deformed when made up - nothing is really square.

It’s a tricky one - I wanted to animate some items being unfolded but gave up on it as it would be cost prohibitive to the client.

Hope that helps a little

Cheers

Andy

P.S. I was looking to use a program or plugin that would allow me to join the edges of the box so when I rotated elements they would be joined together mechanically - didn’t find it though, it would have really helped with one project as it wasn’t a square item but had some awkward internal angles.

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Hi Andy,

Thank you. Yes, exactly, the Ikea type of schematic is also the target. I agree with adding the fillets towards the end, but for the thickness of the paper I always have problems. Your idea with the flat net as a 2D surface is interesting, could you tell me more precisely the steps you used? The problem is to have each panel folded properly with it’s thickness not penetrating another panel.
I’m not sure to grasp fully your point with the flat net 2D surface thing, please kindly let me know more about that. Thank you.

My friend suggested that I should draw each crease as a gutter (with thiner thickness) and then bend the panel fallowing an axis along the crease. I think the idea is interesting but difficult to achieve.

For the look of the surfaces, since mine is thick paper card (and not corrugated board) texture does the trick quite nicely.

As for software, I have Sketchup 2015 with Unfold and Flattery plugins. It’s really good if your models are basic and with not too many complex surface (and no thickness). To join edges and do complex moves and assembly I can’t think of anything but Grasshopper for Rhino Windows. The learning curve on Grasshopper is steep, though, is you have a particular project to work on there’s enough support on the web to reach your goal.

This would be my way to achieve what you are aiming for:

Create a set of curves as a pattern for your creased section:

Extrude to the length of the crease:

Create your cardboard panels in whatever way you prefer, extrusion, surface offset, etc.:

Use the “Bend” - command. Use the red line as your spine, and check the “Limit to Spine” - option:

Bend as required:

The result, not perfect (some bulging near the crease), but maybe good enough:

Hope this helps,
Max.

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Wow Max, Thanks a lot! That’s good!
I couldn’t use the “bend” commend the right way last time I used it, but I’ll give it more work now.
Thanks, that’s a good option.
I’m gonna try that ASAP.
Cheers

Works even better if you select the outer edge of the crease section as the spine:

No bulging, and my guess is that the outer surface is not distorted, so you will be able to use that as the actual cardboard cutting pattern.

Bends > 90 degrees will cause some interference of the panels, but that will probably happen in real life too. Better to create two creases close together then.

Max.

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I experimented with Max’s idea, and it works well with most creases up to 120 degrees of bent.
For a very tight bent at 180 degrees, it is necessary to reconstruct the crease so that the sides don’t overlap.

Thank you very much for helping and sharing!

:grinning: