# llVecDist

*LSL function*

```lsl
float float llVecDist(vector vec_a, vector vec_b);
```

- `vector vec_a`: First vector.
- `vector vec_b`: Second vector.

- Returns: `float`
- Energy: 10

Returns a float representing the undirected, non-negative distance between vectors vec_a and vec_b.

Returns a [float](https://wiki.secondlife.com/wiki/float) that is the undirected nonnegative distance between **vec_a** and **vec_b**.

```lsl title="How to use" frame="terminal"
float result = llVecDist(ZERO_VECTOR, ZERO_VECTOR);
```

## Examples

<details open>
<summary>Example 1</summary>

```lsl
default {
    state_entry()
    {
        vector input_1 = <1.0,2.0,3.0>;
        vector input_2 = <3.0,2.0,1.0>;
        llOwnerSay("The distance between " + (string) input_1 +
            " and " + (string) input_2 + " is: "+(string)llVecDist(input_1, input_2) );
    }
}
```

</details>

<details>
<summary>Example 2</summary>

```lsl collapse={1-9}
//To reset script on touch if the object has been rotated since the last script reset
float gTolerance = 0.05;  //This corresponds to about a 3 degree rotation
default
{
	state_entry()
	{
		llSetObjectDesc((string)llRot2Euler(llGetRot()));
	}

	touch_start(integer total_number)
	{
		if (llVecDist(llRot2Euler(llGetRot()), (vector)llGetObjectDesc()) > gTolerance)
		{
			llSay(0,"This object has rotated. Automatic reset engaged.");
			llResetScript();
		}
	}
}
```

</details>

### Video Tutorial

https://www.youtube.com/watch?v=D0WvH58IWEo

## Notes

- Mathematically equivalent to:
- [llVecMag](/functions/llVecMag/)( **vec_a** - **vec_b** )
- [llSqrt](/functions/llSqrt/)( (vec_b.x - vec_a.x) \* (vec_b.x - vec_a.x) + (vec_b.y - vec_a.y) \* (vec_b.y - vec_a.y) + (vec_b.z - vec_a.z) \* (vec_b.z - vec_a.z) )
- Knowing this, there are ways to circumvent `llVecDist` for more efficient code.
- For example, vector v3 = (v1-v2); v3\*v3 &lt; (f\*f); is over twice as fast as `llVecDist(v1,v2)` &lt; f;

## See also

### Functions

- [llVecMag](/functions/llVecMag/)
- [llVecNorm](/functions/llVecNorm/)

---

*Source: [LlVecDist](https://wiki.secondlife.com/wiki/LlVecDist) on the Second Life Wiki. Content from the Second Life Wiki article LlVecDist (revision 1210534, 2022-03-23), CC BY-SA 3.0.*

---

From lsl.dev: https://lsl.dev/functions/llVecDist/