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how do I rotate float3?

Discussion in 'Physics for ECS' started by Conspiracy, Jan 18, 2020.

  1. Conspiracy

    Conspiracy

    Joined:
    Oct 22, 2016
    Posts:
    40
    I want to rotate a float3 -90 degrees. i.e from (0,1,0) to (1,0,0). I tried to multiply the float3 with quaternion.AngleAxis but that doens't work. If anyone knows how to do this without manually calculating the matrices pls help..
     
  2. Antypodish

    Antypodish

    Joined:
    Apr 29, 2014
    Posts:
    10,775
    New rotation = current rotation * rotation offset
    New vector = new rotation * vector
     
  3. Conspiracy

    Conspiracy

    Joined:
    Oct 22, 2016
    Posts:
    40
    how would I do it in code tho? like I said multiplying quaternion with float 3 doesnt work so....?
    Thanks
     
    DragonCoder likes this.
  4. Antypodish

    Antypodish

    Joined:
    Apr 29, 2014
    Posts:
    10,775
    I suggest look into topics covering adding and subtracting rotations, using quaternions.

    In Dots you of course need use math.mul, instead *
    Order of multiplication is extremely important, when comes to deal with rotations.
     
    erenaydin, Chmyke and Conspiracy like this.
  5. Conspiracy

    Conspiracy

    Joined:
    Oct 22, 2016
    Posts:
    40
    Nvm, I just use matrix calculation.
    For anyone wondering if you wanna rotate float3 to the z-axis just use this formula/code :

    float3 vector
    float3 rotatedVector = new float(vector.y, -vector.x, vector.z)

    basically you just switch the y and x and multiply x with -1
     
    Last edited: Jan 18, 2020
  6. Riderrr

    Riderrr

    Joined:
    Mar 6, 2015
    Posts:
    1
    You can multiply it by cos/sin of target angle. For example:

    Code (CSharp):
    1.  
    2. float angle = -90;
    3.  
    4. float x = 1;
    5. float y = 0;
    6. float z = 0;
    7.      
    8. float3 newVector = new float3(
    9.  x * math.sin(math.radians(angle)),
    10.  y * math.cos(math.radians(angle)),
    11.  z
    12. );