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CAD-Line > STL Import tab

See also : CAD-Line dialog-box

Use this tab if you do not have SolidWorks.

Use STL Import to:

Import one STL file - it will be a CAD-Solid in MechDesigner

Edit the STL File Units to equal those Linear-Units of the original STL file

Edit the Edge Angle Limit to remove facet lines.

Before you save an STL file in your CAD:

Rotate the model in your CAD to the correct orientation relative to the Mechanism-Plane before you import it.

Save the model (in your CAD software) as a Binary STL file-type.

Remember its Linear units.

After you import an STL file:

See Display Options tab to move the STL file in the X, Y, Z-axis directions.

CAD-Line dialog-box

STL Import tab

MD-Dialog-CADLine-STL Import-tab
btn_delkeyword  STL File Import 


The STL file tessellates the surfaces of the CAD model as a mesh of triangles. Each triangle can appear as a small face - a facet. The number of facets is a function of:

the complexity of the original model, and

how accurately you want the STL file to tessellate the original CAD model.

To build complex models, and to import many STL files, you want:

Small file-size for each model

AND each STL file to appear as the original CAD models.

AND not to see the facets on each STL file, or to see only those facets that define real edges in the model.

Strategies to reduce the STL file-size.

Strategy 1:

Reduce the complexity of the original CAD Model = SMALL file-size

Add a new configuration for the CAD model. In the new configuration:

Do a geometry check of the CAD model file to find if it has any small gaps or whiskers.

Suspend small fillets, especially if they do not have a function.

Replace fillets with chamfers, especially along straight edges.

Suspend all fasteners

Suspend fastener holes and hole features.

Suspend all cosmetic details.

Simplify bearing models, and other complex models you may have downloaded from the internet.

Strategy 2:

Reduce the accuracy of the STL file

There are two parameters to control the accuracy of the STL file. These are in the SOLIDWORKS tab.

Linear Deviation :

The maximum Linear deviation (distance) between the surface of the original CAD model and the tessellated surface of the STL file.

Angular Deviation :

The maximum angular deviation between adjacent facets of the tessellated surface of the STL file.

If you do not have SolidWorks, you must find these parameters in your 3D-CAD before you save to the STL file. It is possible they are options in the Save as > STL file-type dialog.

Strategy 3:

Use the Edge Angle Limit parameter - see STL File Import above

STL files may show their facets. You can improve how the facets display with my Magic Number!

Edge Angle Limit = Angular Deviation × 3.14159÷2


Below, the two images are of the same SOLIDWORKS part.

They appear to be identical. However, there is a large difference in the number of facets and vertices.

STL tessellation: Large number of Vertices

STL tessellation: Large number of Vertices

BAD - many facets

Linear Deviation = 0.014mm and

Angular Deviation = 0.4º

There are

119132 vertices

~40000 triangles

The STL file size is 3.5 Mega Bytes

STL tessellation: Few number of Vertices

STL tessellation: Few number of Vertices

GOOD - few facets

Linear Deviation = 0.5mm and

Angular Deviation = 5º

There are:

7533 vertices

2500 triangles

The STL file size is 0.365 Mega Bytes