How To Translate 3D CAD Files into .STL Files: SolidWorks

Additive manufacturing uses 3D CAD files in the form of a .STL (Standard Tessellation Language) file format. This is a standard file format that is supported by most major 3D CAD programs and is frequently used for rapid prototyping. A common question we get in this industry is, “How do I translate my 3D CAD files into .STL files?”  Normally, .STL creation is accomplished by exporting or “Saving As” a .STL file after all manipulations and adjustments have been completed. We’ll do the hard part of getting a machine ready to print your project.

Our Rapid Prototyping programmers have confided in us a few recommendations for file exportation that will culminate in the very best results for your project. Resolution determines, to an extent, how faceted your design will appear once printed. Some additive manufacturing processes require higher resolutions while others will work just as well at a lower resolution. Stratasys Direct Manufacturing offers finishing options that will enhance the appearance of any project and remove all build lines; however, if you require a simple strip-and-ship option, here are our programmers' tips. (Note: This process should work for exporting Blender files as well.)

Customize Before Exporting

First, to save .STL files in SolidWorks, go to "Save As" and select the .STL option.


After selecting the .STL file type, click on the "Options" button to adjust the settings. This is where you can ensure the file saves in a way that will give ideal printed results.


Once the “Option” screen has opened, you will have the decision of saving the file as “Coarse”, “Fine”, or “Custom”.

“Coarse” should be rarely used; “Fine” is a safe bet for FDM, PolyJet, SL, and most 3D Printing processes (depending on platforms). However, it is always best to analyze each geometry on a case by case basis.

“Fine” is a good setting for FDM parts built on SD10 and SD13 platforms, while products built on FDM HD7 platforms, PolyJet, SL, and SL platforms will build best with customized settings due to the small layers these processes and platforms build in. The “Custom” option will allow you to manually adjust the settings for .STL file export.

Before you finalize your exporting, we recommend playing around with the “Custom” options.


“Coarse” settings

Produce a faceted part (file size 183KB):


“Fine” settings

on the exact same part reveal a smoother surface finish (file size 444KB):


By manipulating your

“Custom” settings

with the slider bar (we set our deviation one third of the way at an angle set 80% of the way) the best result is achieved (file size 2.99MB):


Manipulation of the settings is what’s going to give you the best result. The above part now has a very smooth surface, the hole is nice and round and the geometries are clearer. Using the “Custom” setting can take a few tries to get the right surface and reasonable file size, but worth the extra step.

Things to Keep in Mind

If the slider bars on your part are set too high, the part will be very smooth but the file will be very large and difficult to transfer and load. It is important to remember that an extremely large file size does not necessarily equate to a better part. We recommend finding a happy medium between acceptable smoothness and file size. Some faceting is fine and will likely not show up on the printed part. The difference in the surface finish between the part saved with the “Fine” setting and the “Custom” setting pictured here will be so small as to be unnoticeable with most technologies.

Our suggestions also depend on the technology you are using. Fused Deposition Modeling (FDM), for example, is not going to benefit much from severely high resolution because of the nature of the process. A process like PolyJet, however, will greatly benefit from a higher resolution, especially PolyJet HD which prints within very tight tolerances.

Stratasys Direct Manufacturing's engineers are always on-call to help edit and upload your file into .STL from a number of popular 3D CAD file formats, and offer finishing options ranging from sand blasting to painting and vapor polishing.

This article part of a series detailing different ways to export and save files.

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