File Preparation for 3D printing at the Bartlett DMC

Basics

The way you process your three dimensional data will depend on the 3D program you are using to model in. Different programs utilise different approaches to modelling, however, the following points need to be considered independently of your software type:

  1. Ultimately the data you supply needs to be in .STL format.  The three dimensional geometry created in your 3D program can be converted to this file format typically under the File–Export menu of most programs.
  2. All geometry to be 3D printed must be in three-dimensions. Any two-dimensional geometry will not be processed or built by the 3D printer.
  3. All three-dimensional geometry must consist of closed volumes.  Further, all closed volumes must have a minimum of 1mm thickness.  Single surfaces cannot be built.
  4. Generally it is best to unify any parts that are attached in to one file, and surface normals should be correctly orientated.

Some issues can be fixed in our software, but some will need to be corrected first in the native software.  With typical deadlines in mind, it is good practice to bring the model down to us as early as is possible to help identify any problematic data.

Exporting Guidelines

  1. Once you have checked that your file consists of only three dimensional closed volumes you are ready to export your file.
  2. Translate your model to the HOME axis of 0,0,0
  3. Scale your file to final print output size
  4. Change the units in your application to millimeters
  5. Exporting an STL file usually involves the ‘Export’ or ‘Save As’ function. STL is the most common file format for use in 3D printing. Your three-dimensional design will be converted to a three-dimensional triangulated polygon mesh, made up entirely of triangles. STL stands for Standard Triangulation Language.
  6. If your application does not export to STL the next preferred file formats are .3ds and .dwg. This format can be brought into almost any 3D CAD application and exported to STL from there.
  7. Double check your .STL file to ensure it looks right and is to the correct size and scale

Program Specific Guidelines

Rhino

http://wiki.daap.uc.edu/groups/infocenter/wiki/354c5/

http://www.design.upenn.edu/files/preparing-3D-print-files.pdf

Maya

http://tutorialhbaal.wordpress.com/2010/10/17/creating-a-3d-print-from-maya/

 

DMC advice: http://bartlett-dmc.blogspot.com/p/file-preparation.html