How to Calculate Rotation of Points Between Two 3D Points?

  • Thread starter Thread starter simchris111
  • Start date Start date
  • Tags Tags
    Formula Rotation
AI Thread Summary
To calculate the rotation of multiple points between two 3D points, the middle red point can be determined as the average of the upper and lower green points. The other red points should be positioned based on a weighted average of the middle red point and the nearest green point, with the weight influencing the bias towards the green point. However, the limitation of Autodesk Maya's native math nodes, which do not include a weighted average node, poses a challenge. Users can still compute a weighted average using available operations like addition, multiplication, and division. This approach allows for flexibility in determining the rotation of any number of red points based on the green points' rotations.
simchris111
Messages
2
Reaction score
0
I'm working with 3D applications, and I'm trying to figure out how to calculate the rotation of x number of points between two points.

I've made a video to illustrate what I mean:
https://www.youtube.com/watch?v=CmIk8I8itrQ

So the thing is, I need to find some kind of formula that calculates the rotation of the red points based on the rotation of the green ones. The middle red point should always be 50% between the top and the low point, but the red points below and above the middle should bias the rotation towards their closest green point. In this case I have 5 red points, it would be awesome if the formula also worked on more points.


So the formula has to work only from knowing the number of red points, and the rotation of the upper and lower green point.


I'm sorry if this is stupidly simple, but I can't seem to wrap my head around it.
 
Mathematics news on Phys.org
The middle red point seems to be just the average of the two green points, so that's easy. As for the other red points, unless there's some complexity I'm missing, you could probably just take them to be the weighted average of the rotation of the middle red point and the nearest green point; the weight will determine how biased it is towards the green point.
 
Number Nine said:
The middle red point seems to be just the average of the two green points, so that's easy. As for the other red points, unless there's some complexity I'm missing, you could probably just take them to be the weighted average of the rotation of the middle red point and the nearest green point; the weight will determine how biased it is towards the green point.
Thanks for your reply :)

That could work, however I'm limited to my 3D-application's native math-nodes (Autodesk Maya), and it doesn't seem to have a node that can do a weighted average operation. It has an average node, but not a weighted average node.

I'm sorry I forgot to say that in the first post, the math-functionality I can use is limited to these:
Plus, Minus, Avarage, Multiply, Divide, Power, Compose Matrix, Decompose Matrix, Transpose Matrix, Inverse Matrix, Vector Product
 
If you can add, multiply and divide, you can compute a weighted average.
 
Seemingly by some mathematical coincidence, a hexagon of sides 2,2,7,7, 11, and 11 can be inscribed in a circle of radius 7. The other day I saw a math problem on line, which they said came from a Polish Olympiad, where you compute the length x of the 3rd side which is the same as the radius, so that the sides of length 2,x, and 11 are inscribed on the arc of a semi-circle. The law of cosines applied twice gives the answer for x of exactly 7, but the arithmetic is so complex that the...
Is it possible to arrange six pencils such that each one touches the other five? If so, how? This is an adaption of a Martin Gardner puzzle only I changed it from cigarettes to pencils and left out the clues because PF folks don’t need clues. From the book “My Best Mathematical and Logic Puzzles”. Dover, 1994.
Back
Top