Elements and their Graphical Symbols

MechDesigner uses symbols to represent different elements in the graphic-area.

You can change the size of symbols with Application Options | Accessibility.

Symbols stay the same size when you Zoom-in or Zoom-out, as does your cursor [mouse-pointer].

Symbols in the Graphic Area


Planes in the Model-Editor.

The model has three fixed Planes that show in the Model-Editor.

Model Axes in the Model-Editor

The model shows the fixed Red, Green and Blue axes. They locate the '0, 0, 0' position, which is the 'Origin' of the Model.


Planes in the Mechanism-Editor.

The axes on each Plane show the orientation of the Plane. The X,Y and Z axes are Red, Green and Blue, respectively.

Part Outline Symbols

Part-Outline in the Mechanism-Editor

To edit a Part, you double-click the Part-Outline, or use other edit element methods.

The Part-Outline is the symbol for a Part.

The Part-Outline symbol for an Added-Part is oval1s-red
The Part-Outline symbol for a Base-Part is a rectangle2s.

CAD-Lines in Parts

In an Added-Part, the Part-Outline always stays 'wrapped' around a CAD-Line3s.

You must add sketch-elements to the Base-Part.

Pin-Joint Symbols

Pin-Joint in the Mechanism-Editor

The symbol of a 'Grounded' Pin-Joint is equivalent to a 'Dowel Symbol'1s-red, as used in Technical Drawings.
The symbol for a Non-Grounded Pin-Joint is a thick circle2s. It has a slightly larger diameter than the Points that you select to 'make' the Pin-Joint.


Slide-Joint in the Mechanism-Editor

This symbol for the Slide-Joint consists of a narrow1s-red and wide2s rectangle.
The length of each rectangle is equal to the length of each Line that you select to make the Slide-Joint.
A small arrowhead3s identifies the 'positive' direction of the slide-joint. The arrowhead is at the start-Point of one of the Lines.

Part Axes Symbol

Part-Axes in the Mechanism-Editor

The Part-Axes symbols are 'small' in a Mechanism-Editor.
The 'Rusty Red' Axis points along the X-axis direction
The 'Green Axis' points along the Y-axis direction
The Axes of the Base-Part1s-red align with Axes of the Mechanism-Plane
The Axes of an Added-Part2s align with the start-Point of the CAD-Line and the +ve direction of the CAD-Line.


Part Axes Symbol

Part Axes in the Part-Editor

The Part-Axes symbols are 'large' in the Part-Editor.
The length of the CAD-Line maybe longer or shorter than the X-axis.
If you zoom-in, the Part-Axes stay the same size relative to the display, - while the CAD-Line will appear to become longer.
The CAD-Line is 'Dark Green'.

You can use Part-Axes as a Line for dimensioning or to add a new Plane.


Point Symbols

Point symbols in the Mechanism-Editor: Points may be Blue1s-red (Not kinematically-defined), or Green2s (kinematically-defined)

Point symbol in the Part-Editor: Points may be Blue3s (Not geometrically defined), or Black4s (geometrically defined)


'+' : centre-Points (centre of Arcs and Circles)

'O' : start-point or end-point of Lines or Arcs.

'CirclePlus' : start-Point or end-Point that is coincident with a centre-Point

Model Triad in Model Editor

Origin Triad Symbol in Model-Editor

The Triad identifies the Origin and the X,Y and Z-axes of the Machine Frame.

The Red Arrow is in the Global Positive X-direction,
The Green Arrow is in the Global Positive Y-direction. In MechDesigner, +Y is up.
The Blue Arrow is in the Global Positive Z-direction

In this image, Planes are off.

To hide or show Planes, see Filters menu (or toolbar) > Display Filters | Show/Hide Planes.

Velocity and Acceleration Vectors

A Vector Symbol

You can show vectors in the graphic-area when you:

Use the Point: Vector Display and Location dialog-box to show the Velocity-Vector and Acceleration-Vectors of a Point.
Use Force Calculations and show the Force-Vectors and Torque-Vectors.


Function-Block input and output Connector Symbol

The input-connectors are to the left of the Function-Blocks.
The output-connectors are to the right of the Function-Blocks.
Wires are from an output-connector to an input-connector.


Motor Symbol

When you show Forces, the Motor Symbol1s-red that drives a Joint is the 'Power Source'.
This image shows the Motor at a Pin-Joint2s.
You can move the Motor to a different joint, as required.


Spring Symbol

A symbol of a 'Spring'1s-red shows in the graphic-area between the anchor Points of the Spring.


Ball-Joint and Connecting-Part Symbol

The Ball-Joint1s-red has its own symbol.
Edit its radius in the Ball-Joint dialog-box.
The Connecting-Part2s symbol replaces the Part-Outline when you join a Part to a different Part with two Ball-Joints.
Points that are Not Locked

Not Locked

Points that are Locked


The 'Locked Point' Symbol

When you use the Point Vectors and Location dialog to 'Lock and Specify' a Point in a Part, the Points show as 'Small Dowel Symbols'.


Mass Symbol

Profile Mass2s: When you add a Profile, there is an Extrusion that has Mass. A small dowel symbol shows at the Centre-of-Mass of each Profile.
Total Mass1s-red: When you show Forces, the Centre-of-Mass Symbol is a small dowel. The Total Mass is given near to the Centre-of-Mass symbol. The colour of the symbol is the same as the Part-Outline, which becomes a random colour when you Display Forces.
Total Mass = Mass of Extrusions + Mass of Imported Solid + Mass of User Defined Mass.


2D-Cam Contact Points1s-red

When you add a 2D-Cam, the Contact points between the Cam and the Cam Follower are shown as small dowel symbols.

If these Points do not delete when you delete a cam, then edit the Cam-Part, and delete them.



The Symbol for a Motion-Point is a small triangle inside a small circle.

The circle is slightly smaller than the standard symbol for a Point.



The Symbol for a Gear is two involute Gears, 1s-red2s

The Gear-Pair is a kinematic-element - it transmits motion from its input part to the output-part.

You can edit the number-of-teeth, and other parameters.



The Symbol for a Driving Pulley1s-red is a different default colour to a Driven Pulley2s

See Application Settings Graphics > Display colours.

A Belt can drive the Pullets, or a Pulley can drive the Belt.

Why is the Base-Part not Green?


There are 3 possible reasons that the Base-Part is not Green:

1.Visibility toolbar  > Display Forces is active


When Forces are displayed, each Part is given a new, random colour. The Base-Part is a new random colour.


To make the Part green, you should:

Icon-ForceDisplay-OFFClick the Visibility toolbar > Show Forces again

When the icon is grey [left] the Base-Part should be Green.



2.Visibility toolbar > Show other Sketches and Mechanism is active


If 'Show other Sketches in Mechanism' tool is active, and a different Mechanism-Editor is in front of the active Mechanism-Editor, then the Base-Part of the other Mechanism-Editor will show over the Base-Part in the active editor.

If you spin the model you will be able to see the Base-Part of the active Mechanism-Editor.


3.Visibility toolbar > show Model in Mechanism is active

When the Model is being shown in the Mechanism, we also show the Planes. The Base-Part is being partly hidden by a Plane.

To hide Planes, you can either:

Icon-ShowModelinMechIcon-HideModelinMechClick Visibility toolbar > show Model in Mechanism to hide the Model in Mechanism.


- or -

Icon-DispFilt-PlanesClick the Display toolbar > Show/Hide Plane to hide Planes

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