File menu > Open

File toolbar > Open

Top-Tip: How to Restore window size of the 'Save' and 'Open' dialogs

You can open different file-types in the Windows® Open dialog.



CXL is the file-type for a MechDesigner model.

The MTD file-type is the motions in MotionDesigner.

The CXL file and the MTD file should be in the same path.

OLD MODELS: MechDesigner may find a sketch-element that is over-constrained.

A pop-up will ask if MechDesigner can delete the constraint to allow the sketch to be solved. Click YES if you want to open the file. Please re-check the important sketches in the model.

If you are not sure. Save as... the model immediately to a new file-name.

See also: Why so many CXL files?


LXL is the file-type for a MechDesigner Library file.

Before you open a Library file-type, pre-select the Plane onto which you want to add the Library file.

See more: Open LXL File

See also: Save As... LXL file-type


ZXL is a file-type for a MechDesigner ZIP file.

Extract all file-types to one path.

The files include:

CXL and MTD file-types
STL, SLDPRT, SLDASM and DXF file-types that you have linked to CAD-Lines.

The STL, SLDPRT, SLDASM file-types become linked to the path in which you extract the ZXL files.


You can choose to specify the path in which to extract ZXL file-types:

Application Settings | General tab | File Options > Extract ZXL files to:

Create sub-directory automatically ( a sub-directory to the path location of the ZXL file )
Specify ZXL output directory.

I recommend you select Specify ZXL Output Directory. I usually specify the path of the ZXL file itself, but you can also select or create a new path.

See more: File menu > Save as... ZXL file-type.


When you open a DXF file-type, you add a DXF element to the Assembly-Tree as a child to the Model. The DXF element is the container for the DXF drawing.

To show the DXF Drawing in the graphic-area, you must link it to a CAD-Line.

Thus, to show a DXF drawing, there are two actions:

1.File > Open DXF file-type
2.Edit a CAD-Line and use the Cad-Line dialog-box > DXF tab.

You can link the DXF Element and DXF Drawing to one and many different CAD-Lines.

See more CAD-Line dialog-box > DXF tab

btn_delkeywordMEC [Camlinks]

MEC is a Camlinks file-type.

See more: Open MEC files

Why so many .CXL and .MTD files?

If you explore to your model files, you will see many file-types. Why so many files?

They are different backup files


CXL & MTD file-types: the default MechDesigner and MotionDesigner file-types.
ZXL the ZIP file-type for MechDesigner


When you open a model:

1.CXL.n and MTD.n are copied to CXL.n+1 and MTD.n+1
2.CXL.2 and MTD.2 are copied to CXL.3 and MTD.3
3.CXL.1 and MTD.1 is are copied to CXL.2 and MTD.2
4.CXL and MTD are copied to CXL.1 and MTD.1
5.A copy of CXL and MTD are saved to RAM


After every # commands:

1.The copy of CXL and MTD in RAM are saved to ~CXL and ~MTD on disk
2.A new copy of CXL and MTD are saved to RAM

WARNING : You overwrite the original model each Auto-Save

See Application Settings > General tab > File Options to edit:

Number-of-Back-up copies : n
Number-of-Commands between each Auto-Save : #
Do you want to use Auto-Save?
Do you want to save model to ZXL on exit?


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