File Format & File Quality

File Format and File Quality


The STL File

The STL file is the industry standard for rapid prototyping and the format required to get instant on-line quotes. The STL file format is simply a mesh of triangles wrapped around a CAD model. The size of the STL file is driven by two factors, the complexity of the surface and the faceting options used to create the STL file The more complex the surface, the more triangles produced. For example, if using simple geometry (not a lot of curves) the file may only be a couple hundred kilobytes. For complex models, 1 - 5MB file sizes will produce good parts. The key faceting options are Chord Tolerance (deviation) and Angular Control (angle tolerance). These options will change the number of triangles and therefore the faceting or resolution on your STL file. The faceting or resolution will determine the relative coarseness or smoothness of a curved area. Additionally the more triangles placed on the surface of the model, the larger the STL file.

STL (file format) - Wikipedia Definition

 

How do I get an STL file from my 3-D CAD Program?

Having a successful part made begins with the creation of a good .stl file. Here is a collection of information on how to create an STL file from some popular CAD programs:

Alibre

  • File
  • Export
  • Save As >STL
  • Enter File Name
  • Save

AutoCAD

  • Your design must be a three-dimensional solid object to output an STL file.
  • Make sure the model is in positive space
  • Set Facetres to 10
  • At the command prompt type STLOUT
  • Select Objects
  • Choose Y for Binary
  • Choose Filename
  • Choose Stereolithography from Export options
  • Enter the filename
  • Click OK

CADKey

  • Choose Stereolithography from Export options
  • Enter the filename
  • Click OK

I-DEAS

  • File >Export >Rapid Prototype File >OK
  • Select the Part to be Prototyped
  • Select Prototype Device >SLA500.dat >OK
  • Set absolute facet deviation to 0.000395
  • Select Binary >OK

Inventor

  • Click on File > Save Copy As
  • Select STL
  • Choose Options > Set to High
  • Enter File Name
  • Save

IronCAD

  • Right Click on the part
  • Part Properties >Rendering
  • Set Facet Surface Smoothing to 150
  • File >Export
  • Choose .STL
  •  

ProE

  • Click on File > Save As
  • Select the file type STL
  • In the Export STL dialog box, set Format to Binary
  • Set the Chord Height to .001". The field will be replaced by a minimum acceptable value for the geometry of the model
  • Set Angle Control to .5
  • Name the file and click the OK button
  • Pro/Engineer will save your STL file, and display your triangles on the screen

Rhino

  • File >Save As
  • Select File Type >STL
  • Enter a name for the STL file.
  • Save
  • Select Binary STL Files
  •  

SolidDesigner

  • File >External >Save STL
  • Select Binary mode
  • Select Part
  • Enter 0.001mm for Max Deviation Distance
  • Click OK
  •  

SolidEdge

  • File >Save As
  • Set Save As Type to STL
  • Options
  • Set Conversion Tolerance to 0.001in or 0.0254mm.
  • Set Surface Plane Angle to 45.00
  • Save

SolidWorks

  • File >Save As
  • Set Save As Type to STL
  • Options >Resolution >Fine >OK
  • Save

Think3

  • File >Save As
  • Set Save As Type to STL
  • Save
  •  

Unigraphics

  • File >Export >Rapid Prototyping
  • Set Output type to Binary
  • Set Triangle Tolerance to 0.0025
  • Set Adjacency Tolerance to 0.12
  • Set Auto Normal Gen to On
  • Set Normal Display to Off
  • Set Triangle Display to On