Confusion about defining motion using markers

Altair Forum User

Hello,

 

I'm having a little confusion with defining a motion using markers. As seen in attached image, even though all translation and rotations which are available can be defined with respect to marker 2, there is still a selection for marker 1, which seemed irrelevant to me. I have checked the doc page, and what it says about the marker 1 and marker 2 fields is: 'Select the first and second markers to which to the motion is applied.'

 

I find this confusing, as there are translation/motion options only for marker 2. And by intuition, I should need only one marker to define a motion with respect to it. Why do I need to select a marker 1? I would appreciate any information to clarify this.

 

Thank you.

 

Sincerely

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Praful

Motion using Marker means that a motion is given to Marker 1 in relative to Marker 2. So, it is the marker 1 (or the body that marker 1 belongs to) that moves relative to marker 2.

Marker 2 is the reference.