Matching Tranforms returns false though they appear to match

Unity Engine
1

I have the following code:

if (transform.rotation == aimRotation )
            {
                aiming = false;
            }

where the first transform.rotation = “(0.0, -0.1, 0.0, 1.0)”
and the aimRotation = “(0.0, -0.1, 0.0, 1.0)”
yet the statement above never makes it to the aiming = false line. Now the true values for x, y, z do not match as in the -0.1 may actually be -0.0589878 but I am comparing the rotation value not the actual x,y,z. Any ideas why unity sees them as not matching?

2

Well first off whenever dealing with floats, you should never rely on == to work. I’d pick some small value and compare the difference:

if ( Mathf.Abs(floatOne-floatTwo) < .01)
      // Do stuff when they are equal

Secondly transform.rotation is a Quaternion , which is a strange beast all together. It has four member main members w,x,y,z that are coeffeicients to a matrix that describes the objects rotation. Who knows how == is overloaded or how it operates on Quaternions.

Rotations do have a way to get at the x,y,z angles of a rotation though:

transform.rotation.eulerAngles

Does your code necessarily care about the rotation in all 3 dimensions? If you just care about the rotation around the Y-Axis (3D character turning around in the world) you could use :

if (transform.rotation.eulerAngles.y == aimrotation.eulerAngles.y)

OR

if (Mathf.Abs(transform.rotation.eulerAngles.y-aimrotation.eulerAngles) < toleranceValue)

Change the .y to .z if working in 2D

1 Like
3

Thanks. I was doing the == becasue the actual value for the rotation is “(0.0, -0.1, 0.0, 1.0)” in the debug inspector, but you could be right about any overloads that may get more detailed. I found (just to see my scene work) that if I ToString the “(0.0, -0.1, 0.0, 1.0)” value, i get the correct matches, but it is just for testing, too much overhead for that funtion when you have a couple hundred entities all aiming.

I am in 3D on a terrain, so it is possible that an entitiy might point “downward” towards another if it is on a mountain or cliff. I will give you example a run this evening to see if things smooth out.

4

It’s important to note that values in the console will be rounded for readability.

There’s also the Mathf.Approximately function to check if two floats are very close.

2 Likes
5

If you’re comparing rotations you could also check if the angle between them is near 0 or check the dot product to see if they face in the same direction

1 Like
6

Thanks all, will give all of these a look and see what works for my game.