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JBlackhole16-Pearl
16-Pearl
December 12, 2016
Solved

find angles for a 3D rotation

  • December 12, 2016
  • 2 replies
  • 3113 views

to all

I am trying to set up a Find() to see if I can solve the following problem

given a vector in global coordinate system (vglobal) and a vector in a local coordinate system (vlocal) so that the local co-ordinate system has rotated by angle (a,b,c)

can one find these angles? in other words if one knows the starting vector and the final (vector) can one find the transformation

problem is set up (see attached) but the exact syntax for the Find() is failing me

Thanks

Regards

Best answer by Werner_E

Here is a variations which does not limit you to vectors of same length (if only the directions counts) and at least in the example given for some reason unknown to me provides the  "expected" solution:

Regards

Werner

2 replies

V
VladimirN24-Ruby III
24-Ruby III
December 12, 2016

Something like that?

Pic_1.png

    J
    JBlackhole16-PearlAuthor
    16-Pearl
    December 12, 2016

    thanks a lot VladimirN. Much appreciated. Will look into the proposed way of doing it

    W
    Werner_E25-Diamond I
    25-Diamond I
    December 12, 2016

    It would make sense to turn the solve block into a function dependent on the two vectors.

    Of course there are many ways to turn one point into another as long as they have the same magnitude (which is not the case with your example!), so the solve block will stop at the first one it comes by and which may not be the one you have in mind.

    You can use your example, too, if you multiply vglobal by 2:

    J
    JBlackhole16-PearlAuthor
    16-Pearl
    December 12, 2016

    thanks a lot VladimirN. Much appreciated. Didn't think about the function but for the real thing may actually be slightly "neater" approach

    W
    Werner_E25-Diamond IAnswer
    25-Diamond I
    December 12, 2016

    Here is a variations which does not limit you to vectors of same length (if only the directions counts) and at least in the example given for some reason unknown to me provides the  "expected" solution:

    Regards

    Werner

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