How do I convert angle to vector3?

Question

For example I have an object that I want to move at 45 degrees upwards. How do I get the vector coords that I need to push the object at? Thanks

- I want to MOVE the object. Not rotate, MOVE IT. So it moves diagonally 45 degrees. 45 degrees is just an example, I need to find how to convert from angle to vector. I do not want to rotate it, just move.

Answer 1

Answer by Bunny83 · Mar 26, 2011 at 02:24 PM

Bobadebob is right. Everything that involves rotations/angles you need a Quaternion. Just create a quaternion that rotates 45 upwards and multiply your vector2 with it to rotate the direction.

Use Quaternion.AngleAxis to create your quaternion.

var rot = Quaternion.AngleAxis(45,Vector3.right); // that's a local direction vector that points in forward direction but also 45 upwards. var lDirection = rot * Vector3.forward;

// If you need the direction in world space you need to transform it.
var wDirection = transform.TransformDirection(lDirection);

You can of course set up the vector the old, traditional way :D. Just some trigonometry (that's the day your math teacher was talking about)

var angle = 45.0;
var lDirection = Vector3(0, Mathf.sin(Mathf.Deg2Rad * angle), Mathf.cos(Mathf.Deg2Rad * angle));

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Mike 3 · Mar 26, 2011 at 02:25 PM 0

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small note - rot * vec, not the other way around

Bunny83 · Mar 26, 2011 at 02:46 PM 0

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You're right :D there's only an operator for Quaternion * Vector3. I'll fix that

behdadsoft · Aug 31, 2018 at 04:02 PM 0

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Hi @Bunny83

I need know one thing in your code, i seen a tutorial that has a code like your code. This is code:

     public Vector3 DirFromAngle(float angleInDegree, bool angleIsGlobal)
     {
         if (!angleIsGlobal)
         {
             angleInDegree += transform.eulerAngles.y;
         }
 
         return new Vector3($$anonymous$$athf.Sin(angleInDegree * $$anonymous$$athf.Deg2Rad), 0, $$anonymous$$athf.Cos(angleInDegree * $$anonymous$$athf.Deg2Rad));
     }

I don't understand why used Sin and Cos. and I need know why used Sin for X axis and used Cos for Y axis? Could you please explain me?

Tutorial link: link text

TimBur behdadsoft · Aug 31, 2018 at 04:25 PM 0

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This is a math question more than a program$$anonymous$$g question. The sin and cos functions are part of a branch of math called trigonometry. If you're really interested in gamemaking, it would be worth taking the time to learn trig. $$anonymous$$han Academy has a useful set of lessons here.

behdadsoft TimBur · Aug 31, 2018 at 08:00 PM 0

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Thanks for link. I made some games, but i accept my mathematical is weak. i now Y axis is sine and X axis is Cosine in Circle Trigonometry. i know some formula for change Degree to radians and vice versa. I need know Small things because i'm confused, if possible please answer my some little question. because i'm sure your answers help me to better understand.

1- I think this code want calculate angle in radians. right?

2- I know in Vector3, (x,y,z) must be float numbers so sine and cosine return a float number.Sine and Cosine Used for this reason?

3- why sine used for X axis and cosine for Z axis?

Thanks.

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How do I convert angle to vector3?

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