﻿ Kinematic Analysis Tools: Instant Values

# Tutorial 2B: Kinematic Tools

## Kinematic Analysis Tools

We use these tools to show kinematic values at the Master-Machine-Angle [MMA].

We can also plot the kinematic values for a complete machine cycle with a Graph FB.

 Tool 1: Element-Properties dialog-box

The Element-Properties dialog-box is a list of the kinematic values for an element in different coordinate systems.

The kinematic values are for only at the Master-Machine-Angle [MMA]. However, you can move the model to any MMA while this dialog is open, to review the kinematic-values at a different MMA.

Elements that have Element Properties are:

 • Part, Pin-Joint, Slide-Joint, 2D-Cam, Part-Outline, Line, Circle, Arc, Point, Gear-Pair, Function-Blocks, Wire...

To show the Elements Properties dialog-box:

In detail, In the graphic-area:

 1 Hover [move your mouse-pointer above] any element so that it becomes red... [do not click the element ]
 2 CTRL key down + Click the element

The Element-Properties dialog-box is now open.

The two steps above are frequently described as one step: Hover+CTRL+Click.

Note:

 • If you Hover+Ctrl+Click more than one element, the Element Properties dialog-box does not open. You must try again.

Element-Properties dialog-box : Point

For Example: Element-Properties of a Point.

In this case, the Element Properties are of 'Point23', which is a child to Part3 [Element's Part], which is a child to Mechanism [Element's Mechanism].

Properties of a Point:

In the case of a Point, the properties are:

 • 'Part Pos': the Point's vector position within the coordinate-system of the Part.
 • 'Mech Pos': the Point's vector position within the coordinate-system of the Mechanism-Editor.
 • 'Glob Position': the Point's vector position within the coordinate-system of the Model-Editor.
 • 'Velocity', 'Acceleration':
 o i , j : the magnitude of the vector's Velocity and Acceleration , in the X and Y directions, respectively
 o |n| : the total magnitude of the vector's Velocity and Acceleration
 o Θ :  the direction of the vector's Velocity and Acceleration . ['0' is the X-axis direction of the Mechanism-Plane]

'V' indicates they are 'vector' values.

 Tool 2: Trace-Points

A Trace-Point shows the path of a Point on the Mechanism-Plane for a machine cycle.

Other terms for a Trace-Point are: locus, curve, and coupler curve.

You can show any number of Trace-Points.

To show a Trace-Point:

 1 Click Kinematic-elements toolbar > Add Trace-Point
 2 Click a Point in the graphic-area [usually a kinematically-defined chain]
 3 Click in the Command-Manager

Note: If, you do: 2. Right-Click a Point, the Command-Manager accepts the Point and the Trace-Point shows immediately.

SELECT-ELEMENTS DIALOG-BOX

When there is more than one Point that is coincident with a different Point, the Select Elements dialog-box opens.

 1 Click a Point in the Select Elements dialog-box
 2 Click to close the Select Elements dialog-box
 3 Click in the Command-Manager

Do 1-3 again for other Points. , in the same or different Parts.

To delete a Trace-Point

 1 Click the Trace-Point in the graphic-area so that it becomes RED, and also shows in the Selection-Window
 2 Click the 'delete' button on your keyboard.

- or -

 2 Right-click the Point in the Selection-Window
 3 Click 'Delete' in the contextual-menu

Note Useful Information.

If the Point:

 1 Is a Point sketch-element - that is, it not a start-Point, end-Point, or centre-Point of the other types of sketch-elements
 2 ... AND does not have a dimension or constraint that limits its position in the Part-Editor
 3 ... AND has a Trace-Point...

...then, you can drag the Point [slowly] in the Mechanism-Editor and the Trace-Point will update.

The Point must satisfy ALL of 1 & 2 & 3 before it is possible to drag the point and trace-point in the Mechanism-Editor

 Tool 3: Kinematic Vectors: Velocity and Acceleration

To Show or Hide a Point's Velocity and Acceleration Vectors:

See How to open an element's dialog-box, , OR

In the graphic-area:

 1 Double-click a Point on a Part that has a Green Part-Outline

The Point: Vectors and Position dialog-box opens.

 2 Click Show or Hide Vectors
 3 Click the Show Velocity Vector or Show Acceleration Vector, or the two check boxes

Accept the default Scope [Local], and Velocity Vector Options [Mag] [short for magnitude]

 4 Click the button to close the Point: Vectors and Position dialog-box.

Do 1-4 again to show the kinematic vectors of different Points, or to hide vectors for those Points that show vectors.

Note 1:

If necessary, change the colour of the graphic-area, or the vectors, to see more clearly the vectors and the kinematic-values

Note 2:

You can double-click a Point, and the velocity or acceleration vector to open this dialog-box.

Cycle (shortcut 'C') to see the vectors change with each step of the machine cycle.

About the Velocity and Acceleration Vectors in the graphic-area

 • The vectors show only when the Point moves relative to the Mechanism-Plane
 • The length of the vectors are proportional to the Point's instantaneous Velocity and Acceleration.
 • The magnitude of the vectors shows at the arrowhead of each vector
 • The colour [default] of the vectors are Velocity, Acceleration
 • The vectors update their values and length each Machine-Step

Scope Option

The vectors are relative to the:

 • Local xyz axes - Mechanism Axes [default]
 • Global XYZ axes - mODEL-aXES

Velocity Vector Options

The Velocity vectors are the:

 • Magnitude of the Velocity [default]
 • X component of the velocity
 • Y component of the velocity

To scale the vectors:

You can stretch or shrink the length of the vectors. Click the Velocity and the Acceleration (Accel.) buttons in the Feedback-Area.

 1 Click the up button to increase the length of the vectors

- or -

 1 Click the down button to decrease the length of the vectors

Top-Tip - make the vectors very short to see only the magnitude of the vectors near to the Point.

ALT + Click show the 'Instant Scale'

To show the Dimensional Instant Radar Scale:

In the graphic-area:

 1 ALT key down + Mouse-Click

The Instant-Scale shows next to your mouse-pointer.

As you zoom-in or zoom-out the scale also auto-scales.

There are 10 concentric circles.

There are two darker circles, which have the actual dimension value at their radius.

 • Middle Dark Circle [5]
 • Outer Dark Circle [10]

You can linearly interpolate the dimensions of the other circles.

Note: reduce the number of digits to reduce the number of zeros

See Application-Settings > Number-Format.

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