Saturday, December 8, 2012

From 3D to Print - Part 1: Tool Chain

I'd like to preface this by saying: Two posts in one day! Wooo! There now that we have that out of the way...

Earlier today I had mentioned that I was going to be providing a crash course in 3D modelling for later use in 3D printing. There are some gotcha's that you are going to have to look out for. This is not an all in one Turn Key solution. So we want to pay close attention to our steps and make an effort not to have to revisit them along the way.

First, let's examine our tool chain. A tool chain is, simply put, a group of software and possibly other assets used in a specific series of steps every time in order to facilitate coming up with results that will maintain a similar quality every time. Once you get used to doing things in a similar fashion it will streamline the process as well.

The tool chain I use in order to perform my 3D modelling in preparation for printing a model starts with a very simple 3D tool called Milkshape. Weighing in at $35 for a registered license, it's simple and solid, and you can do some pretty complex things with it. The main drawback of Milkshape is that it's simplicity doesn't allow you to do a lot of complex things very easily.

What I mean by this, is that you can in fact make some very complex models in Milkshape, however I like to use it to do the simple stuff first. The learning curve on Milkshape isn't very steep at all and you probably won't end up using the majority of the options in Milkshape. Making 3D models manually in Milkshape can get tedious though, the more complex they get, the more tedious things get. This is why I essentially build a basic model in Milkshape, I call this a "frame" model, because I'm just using Milkshape to draw simple shapes, get the model set up in a rough fashion, and then exporting this rough "frame" model into another software program where I can start adding a lot of detail. A gotcha with Milkshape is that it is very easy to create something called non-manifold edges. The next step in the process, importing to Sculptris, has issues with non-manifold edges. We'll cover this later on in the series though.

After building my basic shape in Milkshape, I will export it to a format called Wavefront OBJ. I then import it into a software called Sculptris. Sculptris is really cool software which allows you to treat a 3D object in the same fashion as a lump of clay. Another great thing about Sculptris: It's Free! By default Sculptris will present you with a perfect circle which you can push, pull, draw on, etc. Sometimes getting this circle into the exact shape you want with any kind of precision can be overwhelming with Sculptris though. If you aren't so worried about things being an exact shape you can simply start in Sculptris if you want. Unfortunately this doesn't work well for non-organic looking things in my experience. Your mileage may vary!

Once I have my image all detailed out using Sculptris, I will then export it again as an OBJ file. From here I will import it into a software called Meshlab. Meshlab has some awesome filters for repairing models and making them less messy over all. It will take some getting used to in order to spot problems on export from Sculptris, but with a little practice you'll soon know which tools to use for various problems in Meshlab in order to make your model come out looking great. The other important thing about Meshlab is it can export directly to Collada .DAE format. This is important for the next step.

So now we have a polished model, but how do the dimensions add up as far as size goes? That's where a nifty tool called SketchUp comes in to play. SketchUp will allow you to actually measure the length of specific sections of your model, or even the entirety of your model and allow you to set size constraints on the model as well. Essentially we are giving the 3D image a real world scale in SketchUp. From here, you export the model as an STL file with the dimensions.

This final STL file can then be sent to a 3D printer, or uploaded to Shapeways, in order to bring your creation to life. It is time consuming yes, but I would say a lot less than creating a master mold of an object modeled entirely out of greenstuff and then mixing plastic epoxies to create your own miniatures.

I will be creating a Resources section on my blog where I will add pages containing this first part of my 3D modelling crash course as well as subsequent parts. I also plan on adding other WH40K resources, such as SVG files for printing symbols and banners on sticker paper, as well as being useful for CraftROBO cutting machines for making paint templates!

I'd love to hear comments and suggestions, as well as anyone else's experiences with 3D Modelling as it pertains to making your own custom plastic miniatures and bits.

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