MechDesigner Glossary-EN

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MechDesigner Glossary-EN

Terminology and Glossary

This glossary lists the terms we use in MechDesigner and this Help documentation

Element-Names - those elements we explicitly add to the model

Derived Element-Names - names that we use to explain the instructions and understand the help

User-Interface - terms for the different areas of the MechDesigner application window, and general dialog-boxes.

Keywords - terms that are generally helpful

Element Names: Derived Element Names

Elements Groups

Element Names

Derived Names


Short Description



... the Model

The Model Element is the machine assembly. This element is always at the top of the Assembly-Tree.




The editor for the machine assembly. To add Mechanism-Editors, Planes and to view the moving model.


Model name-tab :


The tab to select the Model-Editor.



Model Triad :

The Origin and the fixed Coordinate-System of the Model

X-axis (Red), Y-axis (Green) and Z-axis (Blue).




The editor to add kinematic and machine-elements, and build kinematic-chains.  You must add one Mechanism-Editor. You can add many Mechanism-Editors .


Mechanism name-tab :


The tab to select a Mechanism-Editor.



Mechanism-Plane :

The XY-Plane of each Mechanism-Editor.



Mechanism Origin :

The 0,0,0 of the Mechanism-Plane. See also Base-Part.


Master-Machine-Angle (MMA) :

The angle (phase) of the Machine, from 0 to <360.



Machine Cycle

One cycle of the Master-Machine-Angle from 0 to 360




The editor to edit Parts, to add sketch-elements, sketch-constraints and dimensions.




A surface defined by its XY-axes

Mechanism-Plane :


The XY-axes of a Mechanism-Editor

Part Plane :


The XY-axes or a Part


Part / Added-Part.


A Part represents a machine component. Occasionally, it represents a virtual machine-element..



The fixed frame of the Mechanism-Plane

Geared Rocker Part


The Part that is driven by a Gear-Pair

Part-Outline :


The SYMBOL to identify a Part


Derived-Names for Parts


Motion-Part :


A Part in a kinematic-chain whose position is specified with a Motion-Dimension FB.


Rotating-Part :


A Part that rotates around a Point.


Sliding-Part :


A Part that slides along a Line.


Translating-Part :


A Part that moves across a Plane and does not rotate.


Reciprocating-Part :


A Sliding-Part that moves from its original position, then moves in the opposite direction to its original position, again and again.


Oscillating-Part :


A Rotating-Part that moves from its original position, then moves in the opposite direction to its original position, again and again.


Indexing-Part :


A Part that moves progressively in the same direction.


Kinematically-Defined Part :


A Part that has a mobility of zero. It has a Green Part-Outline


Connecting-Part :


A Part we join to other Parts with Ball-Joints.


Added-Part :


A Part. Not a Base-Part.


Free Part :


A Part that has a minimum of one degree-of-freedom. It has one joint with a different Part. It has a Blue Part-Outline.


Completely Free :


A Free-Part that does not have a joint It has a Blue Part-Outline. It has three degrees-of-freedom.




Revolute Joint :

It makes a Point in two separate Parts align; the Mechanism Planes align. Identical to a Revolute-Joint



Prismatic-Joint :

It makes a Line is two separate Parts coincide; the Mechanism Planes coincide. Identical to a Prismatic-Joint



Spherical-Joint :

It makes a Point is two separate Parts coincide; the Mechanism Planes do not coincide. Identical to a Spherical-Joint




A joint to force a circular Profile to have contact with an irregular Profile (or Curve derived from a Point-Cloud).




A Cam that is on one Mechanism Plane.



A Cam that is not one one Mechanism Plane.



The parent to a 2D-Cam in the Assembly-Tree. It can be a parent to one or more 2D-Cams.


Cam Follower


The Profile/Extrusion* of the sketch-loop that defines the shape of the Cam-Follower, which is in continuous contact with the Cam surface. The Profile/Extrusion is a child to a Part.



A Cam-Follower that is circular.



A Part, with a Cam-Plate, that usually rotates continuously in one direction.


Cam-Track, Groove, Rib.

The area between Cam-1 and Cam-2 (the internal and external Cams).  It may be a groove, slot and even a rib.




Two gears that you edit to modify the number-of-teeth, the module, and mesh.




The kinematic element at the output of a gear-pair that is operated by the gear with a motion at the input to the Gear-Pair


Rack & Pinion

Rack Driven Pinion :

Pinion Driven Rack :


The Rack and Pinion element is joined kinematically. Either the Rack motion 'flows' to the Pinion, or the Pinion motion 'flows' to the Rack. The Power may flow in the same or the opposite direction as the motion.

In the Kinematics Tree, the terms are 'Rack driven Pinion', or 'Pinion driven Rack'.




A Rotating Part (Pulley) that either drives a Belt, or a Belt drives the Pulley.


Belt Driven-Pulley :

Pulley Driven Belt :


The Belt and Pulley elements are joined kinematically. Either the motion of the Pulley is found by the known motion of the Belt, or the motion of the Belt is found from the known motion of the Pulley.

Hence, in the Kinematics Tree, the terms are Belt Driven-Pulley, or Pulley driven Belt.




A distance, angle or length

Static Dimension :


A Derived Name. To imply the dimension does not change with time or machine angle.



The Motion-Dimension identifies the Part we will move with a specified motion. We call the Part a Motion-Part.



A driven* dimension between two sketch-elements. You use a Measurement FB to measure in the Mechanism-Editor. (*Driven: we can only observe and analyze its value). The Measurement also gives its first and second derivatives.

Reference Dimension


A dimension that gives a measurement between two sketch-elements that are in two separate Mechanisms


Function-Block ( FB )


Each Function-Block has an output-connector that provides motion-values that can be connected to the input-connector of a different FB. The motion-values at the output-connector are a function of the motion-values at its input-connector, the MMA or the measurement taken from a different kinematic-chain. We use the acronym FB for Function-Block in the help text.


Linear-Motion FB

Clock FB :


A FB whose output mirrors the Master-Machine-Angle (MMA). You can change the phase of its output relative to the MMA with the Linear-Motion dialog-box. WE sometimes use the term Clock as it is equivalent to a Machine-Clock.

Motion FB


A FB linked to a motion in MotionDesigner. The motion-values at its input-connector correspond to the X-axis of the Motion with which it has a link, and the motion-values at the output-connector correspond to the Y-axis of the same motion.

Gearing FB


A FB to apply a simple mathematical function to the input. You can also add a number before and after you multiply the input with the ratio.

Motion-Dimension FB


The Motion-Dimension identifies the Part you will move with a specified motion.

Motion-Path FB


The Motion-Path FB identifies the Sketch-Element in a Part, to which we add a Point at the origin of the sketch-element. A Motion FB will define how the motion moves along the sketch-element.

Point-Data FB


A measurement of a Point – it gives X and Y coordinate motion-values. (Position, Velocity and Acceleration) and also the Magnitude of the Point's motion. The Point-Data can also be used as an independent variable for other FBs.

Measurement FB


A measurement between sketch-elements; to give motion-values. You can use Measurement FB data as an independent variable for other FBs.

Cam-Data FB


A FB linked to a 2D-Cam to calculate Cam-Coordinates and provide data for Cam Analysis.

Graph FB


A FB to show data during a machine cycle

Spring FB


A FB to apply Force between two Points

Force-Data FB


A FB that measures Force or Torque data, at a Point or a Motor.

Design-Set FB


A user-defined collection of Dimensions and Motion-Dimensions from different Parts.

Math FB


A FB to do mathematical functions based on the input variables and parameters.

Stats FB


A FB to do Statistics based on the motion-values at its input-connector

Polynomial Fit FB


A FB to fit, mathematically, with polynomial functions.







The name for the Profile/Extrusion we add in MechDesigner, and also a Solid we can import from 3D-CAD.




Two contours that are offset from the Mechanism-Plane. The shape of the contours mirrors a sketch-loop in a Part.



The filled space between the Profile contours. The extrusion also has other properties: color, transparency, density, moment of inertia, mass.



A convenient Profile; a sketch-loop and a Profile added to a mechanism with one command - Add Auto-Profile.



A cut through an Profile/Extrusion




A dialog to show the exact element-properties.



The locus of a Point that shows on the Mechanism-Plane


Briefcase FB


A tool to put other FB inside - to make the model easier to manage.


Pattern FB


A tool to create copies of a Solid, with their motion anticipated over a machine=cycle.





A Line used to link with a DXF Drawing or STL File.

DXF File


A file that you import (open). It has the standard DXF format.



A DXF element in the Assembly-Tree, put there after you open a DXF file

DXF Outline :


A complete DXF Drawing in the graphic-area. You cannot edit it.

DXF Entity :


A single line, arc or circle entity in a DXF Outline. You cannot edit it.

DXF Drawing


An external DXF Drawing. You can edit it with other CAD.

DXF Layers


A 'sheet' in a DXF Drawing. You can show or hide each DXF Layer.

DXF Origin


The origin of the DXF drawing in the original CAD drawing.


Camlinks Outlines


DXF, or Polyline, that was imported into a Camlinks model, and subsequently imported into MechDesigner. You cannot edit a Camlinks Outline.





One of three trees in the Project-Explorer



Parts joined with Joints, with a minimum of one joint to the Base-Part.

Kinematically-Defined Part :


A Part in a kinematic-chain with a Mobility of Zero. It has a Green Part-Outline

Kinematically-Defined Chain :


A kinematic-chain with only kinematically-defined Parts. All of the Part-Outlines are Green. Each kinematically-defined chain has mobility of zero



A Joint: Lower-Pairs, Higher Pairs and Wrapping Pairs



Perfect Rigid Body. It has an exact length.



Motion-Parts: A Part joined with a Pin-Joint, and its motion is specified by a motion-values at the input-connector of a Motion-Dimension FB.



Motion-Parts: A Part joined with a Slide-Joint, and its motion is specified by motion-values at the input-connector of a Motion-Dimension FB.



A Part whose position is determined by the motion at the input gear (drive gear), the number-of-teeth on each gear, and the mesh (internal or external)

Revolute-Joint (Pin-Joint)


Pin-Joint: A Joint with a Point in two different Parts that are made to be coincident

Prismatic-Joint (Slide-Joint)


Slide-Joint: A Joint with a Line in two different Parts that are made to be coincident.

Spherical-Joint (Ball-Joint)


Ball-Joint: A Joint with a Point in two different Parts - that can also be in a two different Mechanism-Editors - are made to be coincident.

Dyad :


Each Dyads has two Parts and three Joints

R-R-R Dyad


Planar Dyads

The two Parts in a Planar Dyad lie on one Mechanism-Plane.

The joints are Pin-Joints or Slide-Joints.

R-R-P Dyad


RPP Dyad


RPR Dyad


PRP Dyad


SSR Dyad


Spatial Dyads: One Part lies on a Mechanism Plane; the other Part in the Dyad joins Parts in two different Mechanism Planes.

SSP Dyad




Dyad that uses a Motion-Point to guide a Point.



Dyad that uses a Motion-Point to guide a Point.

Kinetostatic Force Terms




The force needed to drive Parts with the motion given to them, given their Mass, and inertia, and any external Force applied to them.




The moment that is needed to rotate a Part with the motion given to it and any other Parts joined to it.




To the left of the Graphic Area



Identify the elements you select in the graphic-area or the Assembly-Tree



It provides hints or instructions for the active command. It may also open a short dialog, where you need to select one or more elements, to complete a command



List the Elements in the Model in various formats

Assembly-Tree :


A hierarchical and chronological List of the Elements you have added to the model

Kinematics-Tree :


A list of the kinematic-chains with Motion-Parts, Dyads and Geared-Rockers that may be in each Kinematic-chain

Geometry-Tree :


A list of Constraints and Dimensions in the sketch-elements. It is only available when you use the Part-Editor.



Message Area


The Area below the graphic-area. It gives you information, warnings and errors for each command that fails to complete.

Hints and Instruction


The hint, with a short instruction, of the active command, or the command as you move your mouse-pointer above a command or tool.

Animation Speed Slider


Tool to speed up or slow down the animation

Force Vector Scale


Buttons to increase or decrease the length of Force Vectors

Torque Vector Scale


Buttons to increase or decrease the length of Torque Vectors

Velocity Vector Scale


Buttons to increase or decrease the length of Velocity Vectors

Acceleration Vector Scale


Buttons to increase or decrease the length of Acceleration Vectors



The Machine Clock.



Number of revolutions of the Machine.





A 'Static' Dimension. Note : it is possible to make a dimension to be a 'Motion Function'.

Smart Dimension


Use the dimension tool to add a Static Dimension: between Points, two Lines, three Points, a Line and a Point, the Length of a Line, the radius of a Circle




A Line has a point at each end - the start-Point, at the Origin of the Line, and the end-Point



An Arc has a Point at each end, and a center-Point.



A Circle. It has a Point at its center, called the center-Point.



A point is a Point!

start-Point :


The Point where you mouse-button-down at the start of a Drag to add a sketch-element or Part

end-Point :


The Point where you mouse-button-up at the end of a Drag to add a sketch-element or Part

center-Point :


The Point at the center of an Arc or a Circle



A 'spline' that you can edit, at each end, its angle, curvature and rate of change of curvature.



A Line that you can use to link and show a DXF Drawing, a SOLIDWORKS, or STL files.



A shape that mirrors the shape of a 2D-Cam or Gear-Pair.



A shape defined a series of 'nodes' with curvature continuity at and between the 'nodes'.


Reference sketch-element


A sketch-element copied from a different Mechanism-Editor. It is orange.

Sketch-Element Constraints



To make two Points, two Lines, a Point and a Line, or a point and X-axis or Y-axis to be at the same location or along the ray of the line or axis.



To make two Circles, Arcs, or a Circle and an Arc, have the same center-point.



To make two Circles or Arcs, or two Lines, have the same radius or length.



To make the Points at the ends of two lines, or a line and an X-axis or Y-axis, to be equally far from each other.



To make two Lines, or Line and an X or Y-axis perpendicular.



To make a Point join to the mid-point of a Line



To make a Line and Circle or Arc tangent, or a Circle and a Circle tangent.



To make a Line or two Points Horizontal.



To make two Points to have equal X-axis