Modeling a character for 3D printing

I’m excited to be trying out the Shapeways 3D printing service. I asked my friend (and esteemed MAKE Editor-in-Chief) Mark Frauenfelder if he’d mind me using one of his wonderful character designs, a cute little fellow called Red Critter. He gave his blessing and I was off.

I built the polygonal model using Autodesk Maya (you could use just about any 3D package, that’s just the one I’m most familiar with). Mark and I went through a couple of revisions to preserve the cookie-cutter appeal of the original. I can tell you from experience that it is rarely simple to realize a 2D character in 3D. This first model was built from as few polygons as possible, which makes revisions easier. I also built him fairly neutral, so I could add a “pose” later.

Since the Shapeways model cost is based on how much raw material you use, I decided to hollow out part of the model, as you can see in the xray view.

Once we were happy with the model, I added a few twist and bend deformations to “pose” him. I also increased the model resolution to around 15,000 quadrangulated polygons so that it would look smooth.

Next, I exported the mesh with the Collada plugin to a format that Shapeways will accept. I uploaded the mesh, chose a material type called “white, strong, & flexible”, and placed my order.

Now, all I have to do is wait for the package — they say it’ll be here in a few days. I’ll post photos once they arrive.

7 Responses to Modeling a character for 3D printing

aris on February 5th, 2009 at 5:57 pm said:

Quick question: does making a fully enclosed hollow cavity actually count? I cannot see a way for the unused material to be removed from the center. Or is it that you pay for how much material is set?

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fabber on February 5th, 2009 at 6:20 pm said:

@aris
Since they use a 3D printer which builds the model up layer by layer they don’t need to hoollow it out, they just don’ ever put anythign there in the first place. Since the fabricating material is the expensive part (other than the machine itself of course) it makes sense that they charge by amount of used material.

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garethb2 on February 5th, 2009 at 8:46 pm said:

This is awesome, John. I SO want Frauenfelderian art in 3D!

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John Park on February 5th, 2009 at 9:06 pm said:

Thanks Gar! His stuff’s awesome; I want to make the full Adventure in Lollipopland collection!

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monkey on February 5th, 2009 at 9:27 pm said:

but if they print layer by layer wouldn’t some of the non-’cured’ material be in there too?

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Colecoman1982 on February 6th, 2009 at 8:59 am said:

The real question is, is their software/process smart enough to know to hollow it out automatically or do you have to include the hollow in your design? If they hollow it out automatically, what if I needed a part to be solid for strength reasons? I would expect that you would have to include a cavity in your 3D model if you want to save material (and, by that token, cost).

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John Park on February 6th, 2009 at 10:09 am said:

Colecoman, they will print what you send them (actually, they check for errors first, such as non-manifold faces or open shells). It’s up to you to hollow it out. If you make a default primitive cube, it’ll print as a solid model.
To hollow it out, you can make a second, slightly smaller cube inside the first and reverse it’s normals. This will print as a hollow model with thin walls. Minimum wall thickness is about 2mm.

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