What's the difference between LThigh_ConPlanes and LThigh_ConNodes?

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1

Hi,

I am still learning from the model(stair_assist_exo.any) from the last seminar. When I read"LCreateConNodesOnExo.any". I found there are two kinds of points, LThigh_ConPlanes and LThigh_ConNodes. What's the difference between them? Here, there is no information about contact planes. Besides, what's their physical meaning? Thanks！

Best，

TJ

2

Hi TJ,

In the file you mentioned ("LCreateConNodesOnExo.any"), there is some explanation provided about ConNodes (short for contact nodes) and ConPlanes (short for contact planes).

  // Contact nodes must be oriented normal to contact surface for the conditional 
  // contact class to work. Nodes are arranged in vertical lines that run across the
  // contact surface of the exoskeleton (except foot base, where GRF prediction is used).
  
  // Contact planes contain reference frames that are needed for the orientation of the 
  // contact nodes. ARel of each Contact plane is referred by contact nodes in the same
  // vertical line (relative to exo). Each node is oriented with z axis normal to the 
  // surface (pointing inwards), y axis parallel to the length of the part (vertical line)
  // and pointing upwards. IN SOME CASES, Y AXIS IS NOT ALWAYS PARALLEL TO THE LENGTH

The Con Nodes must be correctly oriented for the correct definition of the normal in the conditional contact class. Essentially, the Arel of Con Nodes refers to the orientation defined for the corresponding Con Plane. Instead of defining the correct orientation manually for each Con Node, a few Con Planes were defined with the correct orientation.

Best,
Dave

P.S. For other users, the example referred to in this question is available here.

3

Great, I think it is very interesting. I think it is a very effective way. Thanks!

Best,

TJ

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