Compare Vector3

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Hi,how do I compare 2 vectors? Ex: if vectorone is almost the same as vectortwo by a percentage then do something;

I want to be able to do something if the vectors are almost the same , the error being another variable.

Answer 1

Best Answer

Answer by lordlycastle · Apr 20, 2015 at 03:43 PM

You can use Distance as @Sarthak123 showed, that would be the simplest, but won’t give more control over what you wanna do. Writing you own function should be quite simple. You could do something like

 //With absolute value
 public bool Approximately(Vector3 me, Vector3 other, float allowedDifference)
         {
             var dx = me.x - other.x;
             if (Mathf.Abs(dx) > allowedDifference)
                 return false;
 
             var dy = me.y - other.y;
             if (Mathf.Abs(dy) > allowedDifference)
                 return false;
 
             var dz = me.z - other.z;
 
             return Mathf.Abs(dz) >= allowedDifference;
         }
 //With percentage i.e. between 0 and 1
 public bool Approximately(Vector3 me, Vector3 other, float percentage)
         {
             var dx = me.x - other.x;
             if (Mathf.Abs(dx) > me.x * percentage)
                 return false;
 
             var dy = me.y - other.y;
             if (Mathf.Abs(dy) > me.y * percentage)
                 return false;
 
             var dz = me.z - other.z;
 
             return Mathf.Abs(dz) >= me.z * percentage;
         }

You can also write a function that take in a vector to compare in a similar fashion, so you’ll be able to send different values for each element.

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Crystalline · Apr 20, 2015 at 03:51 PM 0

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Thanks a lot, your solution is really useful and what I was looking for!

Bonfire-Boy · Apr 20, 2015 at 04:31 PM 0

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$$anonymous$$inor bugbear of $$anonymous$$e... it's best not to use the word "percentage" when it varies between 0 and 1, because it can confuse the hell out of collaborators and lead to bugs. The word "fraction" does the job.

TheCellCH · Nov 18, 2019 at 10:53 AM 0

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This function as written like this returns the wrong answer doesn't it? We send back false if the distance is higher for x or y this meaning if x or y is not close the function returns what we expect. But for z the distance has to be further away to be true, which is the opposite of what we want.

Correct me if I'm mistaken here.

proandrius · May 09, 2020 at 04:33 PM 0

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It returns wrong answer.

It should be this at the end:

 if ($$anonymous$$athf.Abs(dz) > allowedDifference)
     return false;
 
 return true;

aleksei_sobolevskii · Nov 18, 2021 at 07:42 PM 0

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This is a great answer but not quite right. In the variant with percentage, when you compare abs delta for an axis with a percentage value, the percentage part should also be abs. Consider comparing vectors with negative values.

Answer 2

Answer by Hrungdak · Apr 20, 2015 at 02:44 PM

You can use Vector3.Distance(firstVector, secondVector). It returns a float value that gives you the distance between two coordinates in Unity3d-Units.

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Crystalline · Apr 20, 2015 at 03:31 PM 0

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Thanks It should work.

Answer 3

Answer by Sarthak123 · Apr 20, 2015 at 03:10 PM

It depends on how you want it to be, according to your problem, this might help -

 //UnityScript
 
 var vctr1 : Vector3; // first vector
 var vctr2 : Vector3; // second vector
 var factor : float; // Distance you want between 2 vectors.
 var dis : float; // distance between 2 vectors
 
 function Calc()
 {
 dis = Vector3.Distance(vctr1, vctr2); // Calculating Distance
 if(dis <= factor) // checking if distance is less than required distance.
 {
 //do something
 }
 }

However, if you want to calculate/check on only a single axis, like if you want to know if player has crossed destination in Z-axis, i.e., if player is ahead of destination, then this will be more effective -

 if(player.position.z > destination.position.z)
 {
 //do something
 }

The above process can be used for any axis. Finally, it depends on how you want it, and how you use it.

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Crystalline · Apr 20, 2015 at 03:30 PM 0

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Thanks this should work !

Compare Vector3

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