How do you scale your models to be a certain size when printing?

I've been casually looking at 3D printing for the last 3 months or so. I almost picked up a Robo3D printer in March, but then money got a little tight. Just waiting for money to start coming in as expected again, then I'm probably going to pick up the Robo3D if I haven't decided on a better printer.

In the mean time, I've read a ton of posts on what to expect, what I'll need to have/know, etc. I've also messed around with Blender a little bit and had shapeways print a dog tag I was working on, but I still can't figure out how exactly you get your 3D model to be a specific size. To get the dog tag about right, I just selected everything at once, then in/decreased the size until it was about what I wanted. To check the size, I kept uploading the file to shapeways, which was a bit tedious.

One of the more challenging ideas I wanted to would be to print out a case that with some soldering and maneuvering, I would be able to make a NDS fit inside a 3D printed replica of a DMG model Gameboy. Now obviously with this, unless you just wanted to use a ton of hot glue and leave a lot of space, the measurements to hold things like the cartridge slots, screens, and motherboards would have to be pretty precise. My question is, how would you translate real life measurements into measurements in 3D software. Is that something that would be done in the modeling program, or the slicing program? Any input you have would be greatly appreciated.

TL;DR: I want to make a Gameboy DMG case that the motherboard/screens/etc of a NDS would fit inside, but don't know how to scale the real-life measurements to 3D printing measurements. How do?

 

You can specify the lengths and sizes of the objects you draw in the 3D design program. I can't remember how to do it in blender off the top of my head. In Rhino3D you can specify you're measurements down to 0.001mm. Check out some other 3D CAD software, there's several free programs. If you then want to scale it down or up from you're design you can do this in the printing software, it may use the slicer to do it though. I've done it in Repiterhost, it's really easy.

 

Cool, thanks for the info. I'll go check out Rhino3D when I get a chance. I've heard there are some pretty good ones, I just downloaded Blender a few months back just to see if making anything would be something I'd actually be able to do.

 

YouTube will be your friend for learning. That's pretty much the way I've learnt.

 

To easily check measurments, you can also download Netfabb (free version) and use it to see your sizes. Quick and easy.
Good luck!