An STL is a type of standardized computer exchange file which contains a 3D model. The representation of the surface(s) of the object(s) in the file is in the form of one or more polygon meshes. The meshes in an STL file are entirely composed of triangular facets.
The name "STL" is taken from its extension, .stl, originally because the files were intended for a rapid prototyping process called Stereolithography. The file format has become a world standard for exchanging 3D mesh type objects between programs, and .stl's are now used as input for virtually all rapid prototyping processes, as well as some 3D machining. Nearly all 3D programs can export an STL and most can import them. See below for a list of programs that can export out to a STL file.
Faceting, or flat spots on your part file are relative to the resolution of the .stl file. A good .stl file size is between .5 meg for a simple file to 10 megs for a large complicated part. Generally if your part is outside of these parameters it should be resized.
Open the .stl file in your cad application and look at the faceting to ensure the part appears as designed checking for excessive flat spots on curves and contours. Also double check if your file is in inches or millimeters, some programs such as SolidWorks export in millimeters even if the drawing is in inches. Certain CAD applications do not open .stl files you can download Marcam Viewer which will open .stl files for free.
Resolution Too Low: When the faceting is too coarse you can see flat spots on curved surfaces. The flat spots in the .stl file will show up when the part is produced.
Perfect Resolution: Good .stl files have faceting similar to the files pictured on the left, and are manageable to work with and produce excellent prototypes.
Resolution Too High: while the parts will print when the resolution is too high, it can cause delays in processing parts because of the large size. Increasing the resolution excessively does not improve the quality of the produced part. Please ensure your .stl files are under 10 megabytes.
Repairing Your STL file. Click to download STL Repair.pdf from rhino3d.com
How to save STL file out from some popular programs.
If you do not use one of the following programs try saving your file into a format that one of these can open and then save out from there.
Alibre
1. File
2. Export
3. Save As > STL
4. Enter File Name
5. Save
Ashlar-Vellum
1. File > Export...
2. Select STL Export Type
3. Set Export Options to Binary > OK
4. Enter Filename
5. Save
AutoCAD
Your design must be a three-dimensional solid object to output an STL file.
1. Make sure the model is in positive space
2. At the command prompt type “FACETRES”
3. Set FACETRES BETWEEN 1 &10. (1 Being low resolution and 10 high resolution for STL Triangles).
4. Next, at the command prompt type “STLOUT”
5. Select Objects
6. Choose “Y” for Binary
7. Choose Filename
Autodesk Inventor
1. Save Copy As
2. Select STL
3. Choose Options > Set to High
4. Enter Filename
5. Save
CADKey
1. Choose Stereolithography from Export options
2. Enter Filename
3. Click OK
I-DEAS
1. File > Export > Rapid Prototype File > OK
2. Select the Part to be Prototyped
3. Select Prototype Device > SLA500.dat > OK
4. Set absolute facet deviation to 0.000395
5. Select Binary > OK
IronCAD
1. Right Click on the part
2. Part Properties > Rendering
3. Set Facet Surface Smoothing to 150
4. File > Export
5. Choose .STL
Mechanical Desktop
1. Use the AMSTLOUT command to export your STL file.
2. The following command line options affect the quality of the STL and should be adjusted to produce an acceptable file.
Angular Tolerance - This command limits the angle between the normals of adjacent triangles. The default setting is 15 degrees. Reducing the angle will increase the resolution of the STL file.
A. setting of 1 would mean the height of a facet is no greater than its width. The default setting is 0, ignored.
B. Aspect Ratio - This setting controls the Height/Width ratio of the facets.
C. Surface Tolerance - This setting controls the greatest distance between the edge of a facet and
the actual geometry. A setting of 0.0000 causes this option to be ignored.
D. Vertex Spacing - This option controls the length of the edge of a facet. The default setting is 0.0000, ignored.
ProE
1. File > Export > Model (or File > Save a Copy)
2. Set type to STL
3. Set chord height to 0. The field will be replaced by minimum acceptable value.
4. Set Angle Control to 1
5. Choose File Name
6. OK
ProE Wildfire
1. File > Save a Copy > Model
2. Change type to STL (*.stl)
3. Set Chord Height to 0. The field will be replaced by minimum acceptable value.
4. Set Angle Control to 1 5. OK
Rhino
1. File > Save As Select File Type > STL
3. Enter a name for the STL file.
4. Save
5. Select Binary STL Files SolidDesigner
1. File > Save
2. Select File Type > STL
3. Select Data
4. Click OK
ScanIP
1. File > Export > STL...
2. Select parts for export and export settings
3. Export
4. Enter Filename
5. Save
Solid Designer
1. FILE > EXTERNAL > SAVE .STL
2. Select BINARY MODE
3. Select part.
4. Enter filename.
-
5. Enter maximum deviation distance of .01 MM.
-
6. OK
SolidEdge
1. File > Save As
2. Set Save As Type to STL
3. Options
4. Set Conversion Tolerance to 0.001in or 0.0254mm
5. Set Surface Plane Angle to 45.00
6. Save
SolidWorks
1. File > Save As
2. Set Save As Type to STL
3. Options > Resolution > Fine > OK
4. Save
Think3
1. File > Save As
2. Set Save As Type to STL
3. Save
Unigraphics
1. File > Export > Rapid Prototyping
2. Set Output type to Binary
3. Set Triangle Tolerance to 0.0025
4. Set Adjacency Tolerance to 0.12
5. Set Auto Normal Gen to On
6. Set Normal Display to Off
7. Set Triangle Display to On
Medical Prototypes
Simpleware produces software to generate
STL files directly from volumetric 3D scan data such as CT, MRI,
MicroCT, Ultrasound, etc.
Information provided by Stratasys Corporation