If you are new to 3D printing, take a look at my Blog and on the RepRap Wiki pages.
If you want to explore the sorts of things you can print with a 3D printer, take a look at Thingiverse
Here is how it was designed and printed -
The 3D file is up on Thingiverse here, along with the Sketchup model, go print one out!
A very simple guide to making models that are manifold (valid) for 3D printing -
While I was making the badge in Sketchup I had some of the usual errors you get when joining sections of modelled parts together (the text onto the badge face), so as a guide and tutorial here are a few notes about how to make a simple 'manifold' object for 3D printing.
Objects for 3D printing are usually .STL files, the information in a STL file describes the 'mesh' of the model using points and faces, basically made up of lots of triangles joined together describe the surface and contours of the model.
Typical model 'mesh'
Unlike a photo with a set maximum resolution, you can print a 3D model at any size you like, the triangles just get bigger, so you don't gain or loose detail and with most current fused filament 3D printers, if you enlarge a good model you will see more features being printed that were not possible with a smaller size due to the nature of the filament printing process.
This means that the model has a 'Quality' depending on number of triangles describing the surface, I will go further into model quality in another post shortly, but a basic example is shown below -
Top model uses many triangles and can be considered high resolution, middle is half the quality of the top and the bottom is a quarter of the quality / resolution.
If the mesh is valid and said to be 'manifold' is will have a surface without any defects, these can be holes in the faces, triangles that intersect each other, faces that share the same plane and other odd things like triangles or objects inside other complete meshes that basically make the object invalid.
If a 3D mesh has a problem, it's usually called a 'non-manifold' model, these can be repaired using programs like Netfabb but when designing 3D objects to be printed it's best to try and find and fix problems in the source rather than attempt to repair them later.
Many 3D modelling programs will allow you to join (union) objects together, (the basic free Sketchup does not let you do that automatically) programs like Autocad123D should make a valid mesh out of the two objects, and all you may need to do is remove the part of the object that was not part of the union. But it's always good to be aware of potential issues with 3D.
Example with two cubes -
You can get the sketchup file on the thingiverse page Here
Thanks for looking, and see you for more #30DoC tomorrow.