I'm going to show you guys how to turn almost any 3d shape you have into a real object. I used a regular hot wire cnc. The hot wire cnc is that computer controlled machine that cuts letters out of eps or xps foam. I actually saw an instructable on this site about making a cheap hot wire cnc. Adding a turning table to a foam cutter cnc allows you to make any round shape like columns, vases, spheres, eggs. I'm going to show you how you can create complexe shapes using a turning table. My goal was to make two pieces of 3 meters Anubis. Anubis was a god in egiptian culture with human body and jackal head. I didn't make the 3d figure, I actually found it for free on the internet so I'm only showing you the technique I used to convert a 3d shape into a real life object.
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Step 1: Cut Your 3d Shape to Make It Fit in Your Hot Wire Cnc
The first thing I did was to cut the 3d object in smaller pieces for two reasons: 1. it had to fit in my foam cutter cnc (that is 60 cm high); 2. I only needed the left half of the body for the next process, because, you'll see in a minute that I easily mirrored it.
Step 2: Rotate and Render the 3d Object Using Only Paralel Projection
Very important in this next process is to use "paralel projection" instead of regular "perspective" camera. The next step was to take each and every object piece, rotate it, and render it after each rotation. The program I used had a rotation tool that allowed me to rotate it by 15 degrees. So I rotate every piece 12 times clockwise and made images of it.
Step 3: Convert Your Images to Vector Hot Wire Path
Then I had to convert the outline of every object in every image into a vector tipe. When I converted my patterns to vectors I made sure that, at all times, the hot wire path doesn't go under my foam. You have to make the path of your hot wire to go around like in my picture (my hot wire cnc starts from the right side of the machine).
Step 4: Making a Turning Table for Your Hot Wire Cnc
Now I had my patterns prepared. What I didn't have was a turning table for my foam cutter cnc, so I had to make one. That wasn't so hard. I just cut a circle out of a polywood and made a hole in the middle of it. I also made a similar hole in the middle of my foam cutter cnc table, then I joined them with an appropriate screw for it to spin smoothly. The only things missing from that turning table were the marks for the degrees so I printed a circle with the right pattern.
Step 5: Cutting and Peeling Off
Now I only had to cut out my shapes one by one. One other thing: I early told you that you only need the left half of the body and you will easily be able to mirror it. You don't actually need to mirror the patterns because you'll go crazy. You will need to use the same patterns, in the same order, but, the only thing you have to do is to rotate clockwise if you wat to make, for example, the left leg or rotate counter clockwise if you want to make the right leg. It's that easy! After you finished cutting one object 12 times you peel off the unnecessary remains of foam and you reveal your object.
Step 6: Sanding
Of course it will need a little sanding. You will only need to smooth the edges a little. For less sanding you can use this technique I've shown you, but rotating your object by 10 degrees or less. Of course you will also have alot more vectors to make. It's up to you.
Step 7: Here They Are!!!
I know it looks like alot of work but once you have your shapes in a vector format you will be able to make your 3d object as many times as you want and as large as you want. I was able to make 2 pieces of 3 meters Anubis in like...10 days. So that's it. This is one way to convert your 3d object into a real life object and it's quite accurate. I know there are at least two other methods to do it, using the hot wire cnc, but I didn't make a tutorial about them... yet
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