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A little help here. I recieve 1 rotation per axis from a hardware gyroscope so 3 rotations for 3 axes (x,y,z) in total. When I use a matrix based rotation I get weird rotations perhaps because of the multiplication order (RotX*RotY*RotZ <> RotY*RotX*RotZ), I have also tried MatrixYawPitchRoll but the same effects appear. Thus I concluded that I should use quaternions but as fas as I can think I must create 3 quaternions, one per rotation, but when I combine them with multiplication I get the same effects as a matrix based rotation... So can someone please tell me how to properly use 3 rotations to create and combine quaternions whithout having the appearance of the previous multiplication effects?

P.S. D3DXQuaternionRotationYawPitchRoll still suffers the same effects as matrix based rotation.

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  • the problem you experience is called Gimbal lock. The linked wikipedia page gives details as how to solve it using quaternions (I suppose that the DX function given in question converts them first to matrices, which voids the property of quaternions). Commented Mar 16, 2013 at 1:52
  • thanks didierc for your comment i have already used these transformations... And as far my understanding goes i think that D3DX ready fuction are just a wrapper for these.. Commented Mar 16, 2013 at 2:17
  • @ribben: What are these "multiplication effects" you're talking about? Commented Mar 16, 2013 at 2:48
  • when i am using matrixes and i perform RotZRotYRotX when i rotate the gyroscope at this order X->Y->Z everything seems fine... but the gyroscope must be able to ratate in any order so i get weird rotations... Commented Mar 16, 2013 at 3:03
  • @ribben: A gyroscope cannot gimbal lock. Nor can it change the order in which the rotations apply. Or if it can, then it's a poorly-coded gyroscope. Does it at least tell you when it changes the order of rotations? Commented Mar 16, 2013 at 4:34

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Quaternions are not a magical salve that washes away rotational issues. All quaternions are is a cheap way to represent a specific orientation and to do orientation transforms.

Your problem is that you are not representing your orientation as a quaterion; you're representing it as a 3 angles. And it is that representation that causes your rotation problems.

You need to stop using angles. Represent an object's orientation as a quaternion. If you want to adjust your orientation, create a quaternion from your adjustment angle/axis, then multiply that into the object's orientation. Re-normalize the quaternion and you're done.

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please give me a logic behind you thought.... I have 3 rotations e.g. step 1: create quaternions from axes step 2: .......
@user1070700: Your problem is step 1. Actually, your problem is step 0. You do not have 3 rotations; you have an orientation. As long as you think of your orientation as "3 rotations", you will continue to have this problem.
ok i am open minded and am all ears... But as step 0 is that gyroscope is sending me 3 rotations... Tell me how to manage them to make the proper rotation using quaternions
@ribben: Your problem doesn't seem very clearly specified. A piece of hardware, a gyroscope, is sending you this data. Is the problem the order you're doing the rotations in? Does the hardware not tell you the order to do them in? Are you adjusting the angles later, or is this gyroscope sending you data every frame?
there is a hardware gyroscope from which through serialport and a microprocessor i get three radial speeds (degrees/sec) then at a sample rate 60Hz through integration i transform these values to angles (degrees). The problem here is that the gyroscope it may do a 180 degree at y axis and then rotate only at z or x and cause of multiplication of matrixes (my first approach) this wouldn't show the correct rotation. Thats why i wanted to use quaternion to get rid of multiplication and gimbal lock... Once again thanks for your help!
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I see 2 main source of problems.

  1. Your conversion from Euler Angels is broken.
  2. You use invalid Euler Angle scheme. There are exists 24 types of schemes of Euler Angels http://en.wikipedia.org/wiki/Euler_angles

Simply Euler Angle scheme is order of rotations around axis XYZ, ZYX, ZXZ ...

All conversions to/from matrix/quaternion can be found in source code to excellent article by Ken Shoemake, 1993.

http://tog.acm.org/resources/GraphicsGems/gemsiv/euler_angle/

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