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Convert all the files!

Convert all the files!
Thanks Tom!

It seemed like a simple enough request… While at Milwaukee Makerspace we were discussing creating snowflakes on the Laser Cutter, and I mentioned that there should be some existing art on OpenClipArt.org, but it was down that night, so I jumped over to Thingiverse and found this snowflake.

As a bit of background, I’ve been pretty damn good at file conversions in the past. Audio, video, markup, raster images, anything 2D has been pretty simple. I mean, I’ve been using Photoshop since version 1.0.7. I know how to deal with that stuff… but 3D? It’s a whole new nightmare world!

Snowflake

The file was an STL, which is meant for 3D printing, but we needed more of a 2D vector file. I know how to load a DXF file into the Laser Cutter, so I figured I’m import this STL into Google Sketchup (via a plugin) and then export as a DXF (via another plugin) and that would be it.

Well, that didn’t work. (Oh, and by “didn’t work” I mean I was unable to open the DXF file in Inkscape. At this point I was still waiting to use the Laser Cutter so I didn’t get to try importing it on that machine. I figured that as long as I was waiting, I’d try to get a format I knew would work.) On to the next idea.

I exported the STL from Google Sketchup as a DAE file, and was able to open that in MeshLab. Once again I tried a DXF export, but that one wouldn’t open in Inkscape either. Argh!

Snowflake

So I made a radical decision… Since I could view the file in MeshLab, I just did a screen shot so I could get a nice, clean 2D version of it.

Snowflake

Of course if I had known I was going to do this, I probably could have just done it in Google Sketchup by altering the view… Still, the MeshLab method seemed solid.

Snowflake

I then took the screen shot and opened it in Photoshop, did a little editing, and converted it to black and white. (I considered creating paths, and exporting them, but at this point I wanted to go with what I knew (or thought) would work, and that meant getting a clean PNG file into Inkscape to convert it from a raster to a vector file via trace bitmap.

Snowflake

So finally, I had my SVG file! A vector file I could open in Inkscape and export as a clean DXF file that I was reasonable sure would open and work on the Laser Cutter…

Snowflake

Oh wait, at some point along the way I had created an OpenSCAD file, to test the other DXF files. They wouldn’t render due to some weirdness, but the new one I exported from Inkscape did. This made me feel a little more secure that this file would work.

So how did it turn out? I don’t know!

The Laser Cutter was in use making ornaments, and I couldn’t stay late enough to get a chance to use it.

And just to be clear… while there were many steps in the process above, the whole thing took about 20 minutes from the first file export to getting what seemed to be a good DXF file.

I’ve converted a lot of files in my time, but doing so for these CNC machine is proving to be a new challenge.

Of course half the fun is seeing if it will work, you know, on the machine… which I hope to test at some point. :)

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Simplfying STL Files with MeshLab

Cow (Sketchup)

So back when I first used the MakerBot at Milwaukee Makerspace, my daughter asked me to make her a cow. (The kid likes cows!) Since my 3D modeling skills were not up to the task (and still aren’t, at least not for a cow) I found a cow in the Google 3D Warehouse and brought it into Sketchup.

It looked fine, so I exported it as an STL file and did a print. A very small print. It looked OK (but not great) and since it was small there wasn’t really much detail.

Since then I’ve looked at other files in the Google 3D Warehouse, but since most of stuff there is for screen display and not 3D printing, things tend to be very complex, at least in the well done models. More complex than might be needed for a 3D print, at least from the Makerbot.

I’m still pretty new at this 3D modeling stuff, but simplifying the model seems to be what we want. In the 2D world I’ve been doing the same sort of thing for 20 years, but in 3D? It’s new ground.

Enter MeshLab!

From the MeshLab web site: “MeshLab is an open source, portable, and extensible system for the processing and editing of unstructured 3D triangular meshes. The system is aimed to help the processing of the typical not-so-small unstructured models arising in 3D scanning, providing a set of tools for editing, cleaning, healing, inspecting, rendering and converting this kind of meshes.”

I’m mainly interested in using it to reduce the complexity of 3D models.

Cow Original (MeshLab)

Here is the STL file I created from the original cow in Sketchup, as seen in MeshLab.

Cow Reduced (MeshLab)

Here is the same file after reducing the complexity using the Quadratic Edge Collapse Decimation filter. I still feel like it’s a bit of black magic figuring out exactly what numbers to use, and what checkboxes to check, but this is what I used for this one:

MeshLab Settings

I’m fairly pleased with the results (though I haven’t tried to print it yet) but now that I’ve got a (loose) handle on mesh reduction, I’ll dig into the tutorials on YouTube from MrPMeshLabTutorials, including this one on Decimation.

(Of course I still wish MeshLab had an Undo function.)

Oh, and if you really want to 3D print a cow, this recently added to Thingiverse cow is probably the one you want. :)

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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?