What does director_collection mean specifically？

[Fhy0720]

Hi! I am currently doing some development based on Elastica+RL, but I found that Elastica+RL has stopped updating, so I am looking for help here.
I want to know what self.shearable_rod.director_collection means? I noticed that each element in it is a 3*3 array, which seems to be used to indicate the direction of the rod. But I can't understand its specific meaning. For example, I want to be able to approach a point on the rod vertically along a certain direction. I think this seems to be obtained through the information provided by self.shearable_rod.director_collection[..., x], where x is a certain information point on the rod. But I currently can't understand the meaning of the specific elements of self.shearable_rod.director_collection. Can you help me solve it?
Thanks for your contribution!

[armantekinalp]

Hi @DISCORDzzz

The self.shearable_rod.director_collection represents the frames attached to each element of the rod, organized in a size of 3 × 3 × n_elem. For a more detailed explanation, please refer to this paper, where the concept of directors is illustrated using 𝑄 throughout the text.

[armantekinalp]

Also I am converting this to a discussion since it is a question.