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2D plates from 3D objects

brocstl001

One of my, uh, “hobbies” is figuring out alternative workflows, or ways of solving a specific problem. I often do this with a bias towards open source or free software, because I like to know how to do things, and share how to do things, even when you don’t have expensive commercial software.

If you remember reading about Broc’s model in one of my Digital Fabrication posts, he mentioned using the “Unroll Developable Srf” function in Rhino to create flat pieces. Well, I have access to Rhino at UWM, but any piece of software on my own machines is preferable because I have easy and immediate access to it 24 hours a day, 7 days a week.

Broc's STL in 123D Make

With this in mind, I set about trying to do what Broc did, without using Rhino. I ended up using 123D Make from Autodesk. It’s not open source, but it’s (mostly) free if you’re willing to create an account and share your personal info.

Broc's STL in 123D Make

123D Make has a bunch of nice options for breaking 3D objects into “slices” that can be assembled using various methods. (Supposedly there’s a beta version that does finger joint boxes.) It took a bit of tweaking things, but I was able to create slices just like the ones Broc made in Rhino.

Broc's STL in pieces

The output from 123D Make was a vector-based PDF file with all the parts in 2D.

Broc's STL in pieces

The PDF was easily imported into Inkscape, where it can be set up for being cut by a CNC machine. There’s a minimal amount of clean-up needed to remove any attachment tabs that the application generates. Try as I might, it did not allow me to put a value of zero on some of the parameters. Maybe in the next version. :/

(Oh, you could always print out paper templates and cut things the old fashioned way if you’re not a CNC user.)

Here’s a great promo video 123D Make that shows some of the slicing capabilities.

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3D Modeling Applications

3D Modeling Applications

Well, the time has come… For years I ignored the third dimension, working only in 2D. Even then, I typically favored raster graphics in Photoshop over vector graphics in the likes of Illustrator. Of course the Egg-Bot brought with it the need to dig into Inkscape, and I’ve done well enough there, finding it useful enough for my vector-based tasks… but now comes…. 3D!!!

Now that I’ve got access to a MakerBot, I have this need to deal with 3D modeling software, starting out with converting formats, and eventually designing things on my own, and actually output STL files. So begins my journey, and a look at some of my options:

3DTin
I mentioned 3DTin.com in my last MakerBot post, and while it’s a great way to get started and have something usable in less than 10 minutes, I don’t know that it will be a serious tool for what I’d like to do. It seems to have no concept of converting formats. It’s still a great (although limited) tool, for what it is…

Google Sketchup
Our pals at Google have Sketchup (the free version) which seems pretty darn popular, and thanks to a few awesome plugins, I’ve been able to import and export STL files. (I haven’t tested the printing of any yet, but that will happen soon.) Sketchup confuses me. I should probably spend some time with a tutorial and figure it out. Is the free version limited? I know that they took out the ability to export DXF files in the latest version, and to get that back you’re expected to buy the pro version for $495. Yikes!

Blender
I must say, that without a doubt, Blender is one of the most confusing pieces of software I’ve ever used, and I’ve used Windows… at a large corporation even! I know Blender is powerful, and in the hands of @knellotron or another skilled operator, great things can be done. But even just trying to import and export a file was too difficult. The “File” menu kept disappearing!

123D
From the folks at Autodesk comes 123D. Windows only. I won’t even look at it unless they create a Mac OS X version.

OpenSCAD
Well, there’s always OpenSCAD, the “Programmers Solid 3D CAD Modeller.” But it’s all codey and programmey, and not visual, which may be cool for some things, but it’s probably not the best to start out with…

I even went so far as to fire up Processing and write code to output STL files via the unlekkerLib library, which is outdated anyway and I should be looking at the ModelBuilder library. Argh…..

So that leaves me with a “???” which should be obvious is a question to you: What do I do?