I'm trying to curl branches (curves) vertically on a main trunk but the rotation direction changes based on the z rotation of the starting point. There is also twisting going on. I'm guessing there's a simple answer to this? I am revising the original question to include the problem of bending/curling the main branch - as the previous answer generously provided does not solve this issue of the axis of rotation not working once the main branch changes.
Since you have subsequently changed your question (bent main stem instead of straight, as seen before), this answer is hereby obsolete. This is a pity, and please try to avoid a later modification or always ask your question in such a way that it can be answered clearly. Thank you!
Here would be the solution:
To generate the correct rotation axis in this case, you would simply have to generate the cross product from the positions of the points and the up vector. This will give you exactly the axis per spline point that you show here as the Y-axis (the green axis).
Otherwise, you have done everything right.
PS: It would be fantastic if you could always share your blend file with us in your next questions, because that would simplify things a lot. That way, every time someone has to rebuild your node trees, and that can be quite time-consuming sometimes. Thanks!
$\begingroup$ quellenform. Thanks so much again. so much to learn.. I will figure out how to include blend files here. $\endgroup$– LGoodAug 7, 2022 at 15:31
$\begingroup$ @LGood blend-exchange.com $\endgroup$ Aug 7, 2022 at 15:32
$\begingroup$ @LGood I'd appreciate it if, instead of downvoting an answer, you'd try to clarify in the comments. Because since you changed your question afterwards and also didn't share a blend file at the beginning, this answer hereby became obsolete. Thanks! $\endgroup$ Dec 20, 2022 at 12:47
$\begingroup$ OK - still new to this and wasn't sure how to modify the question after the fact. Next time I will make a new question. $\endgroup$– LGoodDec 20, 2022 at 18:28
$\begingroup$ @LGood No harm done. Please just try to ask the question as focused as possible next time and address only one topic if possible. This way you will get a concrete answer that may help others solve a similar problem. However, please avoid changing questions after a satisfactory answer has been given, because strictly speaking this changes the topic. $\endgroup$ Dec 20, 2022 at 18:52