Dynamic simulation; insert constrain; revolution joint vs point to line joint

[Anonymous]

Hi!

I have a question regarding revolution and point to line  joints in dynamic simulation .

I am going through tutorial  https://www.youtube.com/watch?v=WrTSl1Dq4G4 

by @JDMather    

At 15:06

When  insert constrain is set,

In dynamic simulation sometimes I get revolution joint and sometimes I get point to line joint.

I don’t understand  why it works this way.

Thank you.

[JDMather]

Inventor is helping you out by automatically using a Point-Line rather than a Revolution Joint.

In the real world there would have to be a bit of clearance between the pins and the holes to permit motion without excessive friction.  The clearance would permit a tiny amount of twisting about the axis in addition to rotation.  

In previous releases of Inventor - it would have created a Revolution Joint automatically and then given you a warning about Overconstrained Condition because the arm can not "twist" about that pin as it would in the real world.  The Point-Line permits that twisting Degree of Freedom.

So Inventor is helping you out.  It might help you out incorrectly in some situations in which case you need to take charge and make proper decisions about constraints/joints.

BTW - your pawl is upside down.

[Anonymous]

Thank you!

[Anonymous]

@JDMather,

thanks for your reply!

I have understood you explanation saying

+++++++++++++

Inventor is helping you out by automatically using a Point-Line rather than a Revolution Joint.

++++++++++

But I don't understand why sometimes it is rotational and sometime it is  Point-Line.''

What is the base for making this decision ?

Thanks!

[JDMather]

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@Anonymous wrote:

What is the base for making this decision?

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I have no idea. 
I simply add the appropriate assembly constraints that I KNOW will get converted to my intended DS Joints, rather than having Inventor make the decision for me.

[Anonymous]

Thanks!