Why do we need to define the ARel of AnyRefNodes？

[Taejun (MA Taejun)]

Hi, I know the position (sRel) and orientation (ARel). But why do we need to define the ARel of Foot_Contact_Right？ It is just a point, why does a point have an orientation? Thank you！

Best，
TJ

[Bjorn (Bjørn Keller Engelund)]

Hi @Taejun

AnyRefNode is a derived class of AnyRefFrame so it is actually a reference frame represented as a node, hence it needs an orientation.

Best regards,
Bjørn

[Taejun (MA Taejun)]

@Bjorn

AnyRefNode is a derived class of AnyRefFrame so it is actually a reference frame represented as a node, hence it needs an orientation.

But I am still a little confused about this. In this case, I wonder why Foot_Contact_Right needs Arel while ToeNode_Left does not? What's the difference between these two frames?

[Bjorn (Bjørn Keller Engelund)]

Often the foot coordinate systems are aligned so positive z-directions point medially - that is not the default of anybody, hence the flipped node.

Best regards,
Bjørn

[Taejun (MA Taejun)]

@Bjorn

the flipped node.

Sorry， but I still can't get the meaning of the flipped node. Could you please give me some examples of this kind of node？

[Bjorn (Bjørn Keller Engelund)]

The coordinate systems of the feet are aligned so the positive z-direction points medially. The Arel orientates the coordinate system correctly.

Best regards,
Bjørn