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Old 9th August 2014, 11:46 PM   #3
Edymnion
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Default Re: Going from AC3D to .stl

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Originally Posted by MikeM View Post
I'm a long time, but occasional user, of AC3D - mostly for rapid sketches of industrial kit and machinery - so no 'pretties'. I now want to try and make some pieces for a laboratory experimental rig using 3d printing, and rather than struggle to learn Solidworks, would love to do it in AC3D. However there seem to me to be a couple of issues I don't understand.

1 How do I make the dimensions 'real world' instead of grid units? If I want a 100mm disk - I can make it 100 units diameter, but how does the conversion to .stl know what this means?

2 What happens to surfaces that are hidden when you merge two pieces. Even if you weld the vertices there are internal surfaces, often hundreds if trying to make smooth curves to accurate dimensions

Thanks in advance for any comments
You're in luck, I just happen to have gotten a 3D printer that runs off of ReplicatorG (which uses .stl as it's primary format).

The unit conversion is 100 micron = 1 small square in AC3D. Which makes one big square a millimeter.

However, working in that large of a scale is kind of impractical, the ReplicatorG software (the stuff that runs Makerbot) has a scale option built into it. I model mine at 1 small square = 1mm, 1 big square = 1 cm, and then when I import the stl into ReplicatorG I simply scale it all up by a factor of 10 to get a piece it likes.

One other thing to watch out for, stl format likes to lay things on their side. As in, any normal mesh you open with practically any program loads rightside up, the stl rotates it 90 degrees on the Z axis.

I've attached an image of a piece I'm printing out right now. The small one is the one I modelled in AC3D, the big one is the same one after I've rotated and scaled it properly in ReplicatorG for it to print the way I wanted.
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