Could you tell me if Quaternion (-Q0, Qx, Qy, Qz) is exactly the same as (Q0,-Qx, -Qy, -Qz)?
I am testing a SW tool against a formula and I have noticed that sometimes the signs are different.
The calculated position of an object in 3D space, from a SW tool, is as follows: Quaternion (-Q0, Qx, Qy, Qz) From a formula, I obtained: (Q0,-Qx, -Qy, -Qz)
No, they are not the same quaternion. One is the negative of the other. Whether they achieve the same result in an operation depends on the operation. If you are only concerned about the final orientation of the rotation represented by the two different quaternions, then they represent the same final orientation. But if you feed these two different quaternions into a control algorithm, then one will generate commands to physically rotate the object the "short" way around, and the other will generate commands to physically rotate the object the "long" way around. Whether this difference means anything to you depends on your application.