See also : CAD-Line dialog-box

See also : Globe-wwwGetting Started Tutorials > Import SOLIDWORKS Parts and Assemblies - (Internet connection)

Use the CAD-Line dialog-box | SolidWorks tab to import a Solid:

1.Import one SolidWorks® Part or Assembly document: see also Mass Properties

- or -

1.Import one STL file
2.Show or hide the Solid, change its accuracy, transparency, and colour.




tog_minus Import from SOLIDWORKS 


You must click two buttons: STEP 1: Read buttonRed-14-2 and WAIT, then STEP 2: Import buttonRed-14-12.  The other buttons are optional.

To see the model in Mechanism-Editors you must use Visibility toolbar > Show Model in Mechanism



ButtonRed-14-2 : Read : to read the active SolidWorks® document file-name you want to link with the CAD-Line.

Please WAIT to establish the connection with SolidWorks®. Read the messages in the Feedback-Area.

BOXES (Red-14-4Red-14-5Red-14-6) - after you click ButtonRed-14-2

SolidWorks Part / Assembly Red-14-4 (Read-Only) - SolidWorks® file-name, with its full path
SolidWorks ConfigurationRed-14-5 (Read-Only) - name of the active SolidWorks® configuration
Current Model StatusRed-14-6 (Read-Only)Red-14-8
Unavailable - before you import SolidWorks® document.
Out of Date - if the date/time of the file in boxRed-14-4 on disk memory is older than the current date/time.
Up to Date - if the date/time of the file in boxRed-14-4 on disk memory is the equal to the current date/time.

Optional Buttons(Red-14-1bRed-14-2) : When a SolidWorks® document file-name is in boxRed-14-4, you can use:

ButtonRed-14-1b: Remove : to remove the SolidWorks® document from the CAD-Line and boxRed-14-4

ButtonRed-14-3: OPEN : to open the SolidWorks® document in box Red-14-4 in SolidWorks , or open SolidWorks if it is not open

OPTIONAL Parameters : use before you import the model:

Coordinate SystemRed-14-8 :  select a Coordinate System if there is more than one in the SolidWorks® document.

File Quality Red-14-10a - control the linear and angular deviation and thus the accuracy of the Solid model

Fine: more vertices
Coarse: fewer vertices
Custom :  must be active to edit the Linear Deviation and Angular Deviation parameters.

When Custom is active you can edit the quality (and thus size) of the STL file.

Linear DeviationRed-14-7: Maximum =0.5mm; Minimum =0.014mm
Angular DeviationRed-14-9: Maximum =30º; Minimum =0.4º

See Below : Edge Angle Limit parameter


Button : Import Model Red-14-12

2.Click Red-14-12 to import the SolidWorks document in boxRed-14-4 onto the CAD-Line.

MechDesigner saves the document as an STL file-type and then imports that STL file onto the CAD-Line.

The STL file-name is: Document Name-Configuration-Name.STL

Optional Button

Button : Rename CAD-Line to SolidWorks Part name Red-14-11

Top tip: if you hover above the boxRed-14-4, the full path and file-name shows as a tool-tip, and in the 'Extended Hints' box.

After 3 seconds, the full file name disappears as a tool-tip, but not from the extended hints box.


Tile SolidWorks and MechDesigner applications before you use the Import button, to see any messages that may show in SolidWorks.

Pop-up in SolidWorks

Pop-up in SolidWorks

1.Expand the Display Options separator. The Number-of-Vertices will be >0 after the document has been imported. A large file can take some time to import - be patient!
2.Files that you download from the internet - for example a Servomotor - can be huge. Try to reduce their size before you import them, or do not import them!
3.Suspend Fillets. Always suspend Fillets in the SOLIDWORKS file. Use Chamfers if possible, they are much more efficient.
4.Suspend Cosmetic Threads.

tog_minus Display Options 

Dialog-CADLine-SW-Display Options

Show / Hide the Model

Click Show model check-box to show the Solid that is on the CAD-Line.

Note: You must also do Visibility toolbar > Show Solids in Mechanism to show Solids in the Mechanism-Editors


Drag the Transparency Slider-Bar to change the transparency of the CAD-file on the CAD-Line. Experiment!

Solid colour:

Click the Solid Colour button to open the Windows® colour picker

Number of Vertices: (read-only)

Complex files have more vertices. MechDesigner becomes slower when the Number-of-Vertices is very high.

How many is too many? It depends on your PC.

Experiment with the Fine, Coarse and Custom radio buttons in the 'Model import from SolidWorks' separator.

Try to make Number-of-Vertices < 20,000.

Top Tips:

Make a new SOLIDWORKS Configuration if there are many features that add vertices for cosmetic reasons.

In the new configuration, reduce the number of vertices:

Remove Fillets, cosmetic fillets.
Use Chamfers to show model edges.
Do not import models with balls in ball bearings!
Make the model as simple as possible.

tog_minus STL File Import 

When do you need to import STL files?

When you do not have SolidWorks.
You have or can save a model as an STL file.


STL file that you save from CAD do not have a Coordinate System.

Before you save the original CAD part as an STL file:

oMove the original CAD part so that its Origin, X–axis, and Y–axis coincide with the Origin,  X-axis, and Y–axis of the CAD-Line in MechDesigner.
oMove the original CAD part along the Z-Axis, to move it relative to the Mechanism-Plane in MechDesigner - or see below CAD Solid XYZ Position.
Save the STL file in Binary Format and in SI meters



To import an STL file

CAD-Line dialog > SolidWorks tab > STL file import separator:

1.Click the Browse button
2.Select an STL file (Binary)
3.Click the Import STL File Button:

Look at the model in MechDesigner. If you can see many 'edges':

4.Increase the Edge Angle Limit parameter - see Edge Angle Limit magic number below
5.Re-import the STL file

Edge Angle Limit

Change the apparent quality of the STL file in the graphic-area.

The Edge Angle Limit parameter analyses the angle between two adjacent facets in the STL file.

If the angle between two adjacent facets in the STL file is less than the Edge Angle Limit parameter, then we do not show the edge between the two facets.

If the angle between two adjacent facets in the STL file is greater than the Edge Angle Limit parameter, then we do show the edge between the two facets.

Magic Number for Edge Angle Limit to removed unwanted edges from facets.

Enter in the Edge-Angle Limit box: Angular Deviation (its actual value from its parameter value box - above - not the words! ) * pi / 2

Compare the top image, to the left, with the bottom image.

Angular Deviation =  8º

In the top image the Edge Limit Angle parameter = 6º.
In the bottom image the Edge Limit Angle parameter = 8*pi/2 =  12.56637º.



tog_minus CAD Solid XYZ Position 


After you import the SolidWorks document, if it is not in the correct place, you can move it in the X, Y and Z axis direction.

You cannot rotate the SolidWorks document. If necessary, rotate it in SolidWorks before you import it to MechDesigner.



STL files render the surfaces of CAD models as a mesh of triangles, in a process called tessellation.

The number of triangles, and thus the STL file-size, is a function of the complexity of the original model and the accuracy at which you define the tessellation.

Note: The Number-of-Vertices is proportional to the number-of-triangles, and, thus,  an indication of the STL file-size.

Strategies to reduce the STL file-size.

Reduce the Complexity of the Original CAD Model

Model designs that have small gaps' and very small whiskers adversely affect the quality of the original model. Therefore, before saving to STL file,  perform a geometry check of the model files.

I find it helpful to add a new CAD model configuration, in which I will make the changes that reduce the STL file-size.

In the new configuration:

Suspend small fillets, especially if they do not have a real function.
Replace fillets with chamfers, if possible, especially along straight edges.
Suspend all fasteners
Suspend fastener holes and hole features.
Suspend all cosmetic details.

Reduce the accuracy with which you save the STL file

We instruct SolidWorks to save the model as an STL file, which we then import onto the CAD-Line in MechDesigner.

We use two parameters in MechDesigner to control the accuracy of the STL file

Linear Deviation:


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

In Import from SolidWorks above : Maximum Linear Deviation is 0.05mm.

Angular Deviation:


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

In Import from SolidWorks above : Maximum Angular Deviation is 23º.

STL Appearance in MechDesigner

STL with a only few vertices can be faceted. Before you decrease the Linear or Angular Deviation parameters, see if the Edge Angle Limit parameter will help.

If you save the model as an STL file from other CAD, then look for Angular, Linear or Chordal Deviation parameters, or similar options, before you save the STL file.

Tutorials and Reference Help Files for MechDesigner and MotionDesigner 14.2 + © Machine, Cam, Mechanism, and Motion Design Software by PSMotion Ltd