Being a Trekkie with access to a 3D Printer, I just had to try my hand at designing my own rendition of the U.S.S. Enterprise and making a 3D print of it. I used OpenSCAD to create a simple version of the Enterprise, exported the design into a STL file, and used the ReplicatorG software and a MakerBot Replicator to print the design.

The printed Enterprise is 3.5" long, 2" wide, and 1" deep. I used gold colored ABS filament to make the print. The printed Enterprise and the OpenSCAD view of the model are shown in the attached photos.

I made this at TechShop.

Step 1: Materials, Tools, and Software

To make the Enterprise I used the following materials, tools, and software:

Materials:

1.75mm width Gold ABS filament from Octave Systems

Tools:

The 3D printer I used was a MakerBot "Replicator" at TechShop.
A set of small hand cutting tools to remove excess support structure material from the model. I used the "3D Printer Tool Kit A" from Octave Systems. You could use an Xacto knife and dental tools as well.
A small pair of needle nose pliers also used to remove support structure material.

Software:

OpenSCAD - a script based free open source 3D modelling software. You could also make the model with 3D modelling software like Autodesk Inventor.
ReplicatorG - free open source software for converting the output of OpenSCAD into the instructions used by a 3D printer.

Step 2: Design in OpenSCAD

I created the design with OpenSCAD. OpenSCAD is different than most 3D modelling programs: rather than do your design with a graphical user interface, you write scripts that define the geometric shapes of parts of your model and the placement of those parts. I used OpenSCAD because I have a programming background and I wanted to see the difference between the two approaches. OpenSCAD is powerful, but in hindsight, it would have been much faster and probably easier to do this simple design using a graphical 3D modeling software like Autodesk Inventor or 123D Design.

Basically what the OpenSCAD script does is:

define the saucer section (two cones attached to each other on the wide ends)
define the engines (a sphere half embedded in the front of a cylinder, a cone attached at the rear, and a rectangular solid at an angle to connect to the main body)
define the main body (a sphere half embedded in the front of a cylinder and a trapezoidal solid attached to cylinder and the saucer section)

Various views of the model are shown. The colors have no effect on the 3D printed model - I used the colors to help me debug the script and get proper placement of the parts.

After I was satisfied with the design, I created a STL file of the design using the "Save As..." option in OpenSCAD as shown in the last screenshot.

The OpenSCAD script and the STL file are attached.

Step 3: Making the 3D Print

To make the 3D print of the model, I opened the STL file in ReplicatorG, sized it and placed it on the printing platform, and then used the "Generate" command to generate the instructions (GCode) used by the 3D Printer to print the design. The settings I used are shown in the first screenshot. One of the important options I used was the "Exterior Support" option - the saucer section and engines must have support during printing.

The next three screenshots show various views of the model in the ReplicatorG software. It took 1 hour and 52 minutes to print the Enterprise.

Step 4: Remove Raft and Support Structure

The photos in this step show what the Enterprise looked like after the printing finished. The model had a cocoon of support material around the bottom. This support material ensured that the saucer section and engines did not droop or sag during printing. In the last two photos, you can see the raft that the model was built on and the support material after the raft was removed.

To clean up the model, I gently pulled off the raft. I then removed as much of the support material as I could by gently tearing it off. For the most part, the raft material easily pulled off. I used needle nose pliers to remote any stubborn pieces and then used the cutting tools to remove any additional excess material.