File menu > Open

File toolbar > Open

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

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



CXL is the default file-type.

The MTD file-type, with the same file-name, should be in the same path as the CXL file. The MTD file-type has the motions that are needed for the model.

See also Why so many CXL files?


LXL file-type is the Library file-type.

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

See Also Open LXL File

See also Save As... LXL file-type


A ZXL file is a ZIP file-type.

File > open > ZXL extracts the files CXL and MTD file-types.

If the ZIP file includes STL, SLDPRT and DXF files, then these are also extracted from the ZXL file.


Use Application Settings | General | ZXL Output file location to specify two path options for extracted files.

Create sub-directory automatically... a sub-directory of the ZXL file.
Specify ZXL output directory. -I recommend this option, I usually specify the same path as the ZXL file itself.

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


File > Open > DXF file-type adds a DXF element to the Assembly-Tree. The DXF element is the 'container' for a DXF drawing.

To show the DXF drawing, you must link the DXF-element to a CAD-Line.

See also CAD-Line dialog-box > DXF tab

tog_minusMEC [Camlinks]

MEC is a Camlinks file-type.

Notes: The MEC file-type is available to open only when a Mechanism-Editor is active.

See also Open MEC files for more details.

Why so many .CXL and .MTD files?

If you explore to the path for the model files, you will see many files with the same file name but different file-extensions. Why is this?

They are files that MechDesigner creates automatically:

Auto-save option : check-box
Number-of-Backup files ≥ 0

These are set in Application Settings > General tab > File Options Separator

When the 'Number of Backup-Files' is set to three(3), and you open a MechDesigner file, it follows that:

1.If *.CXL.2 is found, we rename it to *.CXL.3
2.If *.CXL.1 is found, we rename it to *.CXL.2
3.We copy *.CXL to *.CXL.1
4.MechDesigner opens the *.CXL file.
5.Also, as above for the MotionDesigner *.MTD file:

To open a file with .1, .2 or .3 in the file-extension,

1.Delete the .1, .2, or .3 from the file-extension


Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd