Getting Started Tutorials - MotionDesigner > Tutorial 5: Edit the Start of Traditional Motion-Law

Edit the Start of a Traditional Motion-Law

With a Traditional Motion-Law you can specify the Start-Position and End-Position.

You CANNOT (usually) edit the Velocity, Acceleration, or Jerk at the Start and End of the Traditional Motion-Law.

The velocity and acceleration values are usually zero at the Start and End of a Traditional Motion-Law.

In this Tutorial, we show you how to edit the Start-Position of a Traditional Motion-Law.

We cannot edit the Velocity, Acceleration or Jerk values at their Start or their End, They are defined by the mathematical definition of the Traditional Motion-Law.

We consider the two cases:

How to edit the position at the start of a Traditional Motion-Law when:

Case 1: The motion-law of the Previous-Segment is a Traditional Motion-Law.

Case 2: The motion-law of the Previous-Segment is a Dwell Motion-Law.

VIDEO

How to...

Edit the Start of a Traditional Motion-Law


In the image above, the: Selected-Segment (RED) is Modified-Trapezoidal - a Traditional Motion-Law. Previous-Segment is Dwell - also a Traditional Motion-Law.
Start Blend-Point Editor	To edit the Position at the End of the Dwell - when it is the Position at the Start of the Modified-Trapezoid 1.Click the Modified-Trapezoid Segment - so that it becomes the Selected-Segment 2.Click the Blend-Point and Segment toolbar > Start Blend-Point Editor icon
Blend-Point Editor Y-axis Position Values MODIFIED-TRAPEZOIND is the Selected-Segment
In the Y-axis Values separator of the Blend-Point Editor : The End-Position Control-Button and the Start-Position Control-Button are READ-ONLY. Thus you cannot enter a value in the data boxes ! First Remember: Start-Position = Start of the Selected-Segment (the Modified-Trapezoid) End-Position = End of the Previous-Segment (the Dwell) Why are they READ-ONLY?
Definition 1 :	DWELL: Position at End of Dwell = Position at the Start of Dwell
Rule 1 :	Dwell: You must edit the Start-position of the DWELL Segment
	Rule 1: Select the Dwell segment 3.Click the Previous-Segment icon in the Blend-Point Editor.
Blend-Point Editor Y-axis Position Values DWELL Segment is the Selected-Segment
The Dwell Segment is now the Selected-Segment. We cannot edit its Start-Position. Again, why? a MotionDesigner Rule:
Rule 2 :	If the Match Control-Button is active, ... you must edit the end-Position of the Previous-Segment (to the Dwell-Segment)
	Rule 2 : 4.Use the Spin-Box (or enter a value with your keyboard) to edit the End-Position of the Previous-Segment. In the image below, the End-Position=100 Notice : Start-Position (of the Dwell Segment) = 100 This is because the Match Control-Button is active.
Blend-Point Editor Y-axis Position Values DWELL Segment is the Selected-Segment
SUMMARY: How you must edit the Start of a Traditional Motion-Law when the Previous Segment is a Dwell. Select the Dwell Segment ... ... edit the End-Position of the Previous-Segment to the Dwell ... automatically, the End-Position of the Dwell Segment = Start-Position of the Dwell Segment (see Definition 1 of DWELL: End-Position=Start-Position) ... automatically, the Start-Position of the Modified-Traditional segment = End-Position of the Dwell Segment Note: The above statements are with Match-Control Buttons = active.


In the image above, the: Selected-Segment (RED) is Modified-Trapezoidal - a Traditional Motion-Law. Previous-Segment is Modified-Sinusoid - also a Traditional Motion-Law.
Start Blend-Point Editor	To edit the Position at the End of the Modified-Sinusoid - when it is also the Position at the Start of the Modified-Trapezoid Motion-Law 1.Click the Modified-Trapezoid segment - so that it becomes the Selected-Segment 2.Click the Blend-Point and Segment toolbar > Start Blend-Point Editor icon
Position Values in the Blend-Point Editor
In Y-axis Values of the Blend-Point Editor (see image above) 3.Make sure the Specify End Position Control-Button is active 4.Make sure the Match Control-Button is active 5.Edit the End-Position with the Spin-Box tool, or use you keyboard to enter a new motion value. The End-Position value is the position at the end of the Modified-Sinusoid Segment CASE 1 is easy and the normal case.
Question: Why are the Velocity, Acceleration, and Jerk Control Buttons disabled? Answer: You cannot edit them. The motion-derivatives are defined by the mathematical function for the Modified-Sinusoid and Modified-Trapezoid segments. The Velocity and Acceleration values are zero - by definition of the Mathematical Function - the Motion-Law.