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DarkScience

Vector to Angle , and vice versa

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I'm currently trying to figure out how to convert XYZ to PYR. Here are my classes.

Also i'm currently looking it up. I know of sin/cos. I'm learning what i can from online docs.

Vector:
[SPOILER]

#region Properties
public float X;
public float Y;
public float Z;
public float Forward { get { return Y; } set { Y = value; } }
public float Right { get { return X; } set { X = value; } }
public float Up { get { return Z; } set { Z = value; } }
#endregion
#region Constructors
public Vector( )
{ X = 0; Y = 0; Z = 0; }
public Vector( float x , float y )
{ X = x; Y = y; Z = 0; }
public Vector( float x , float y , float z )
{ X = x; Y = y; Z = z; }
#endregion
#region Methods
public Vector Normalize( )
{ }
#endregion
#region Operators
public static Vector operator +( Vector vector1 , Vector vector2 )
{ return new Vector ( vector1.X + vector2.X , vector1.Y + vector2.Y , vector1.Z + vector2.Z ); }
public static Vector operator -( Vector vector1 , Vector vector2 )
{ return new Vector ( vector1.X - vector2.X , vector1.Y - vector2.Y , vector1.Z - vector2.Z ); }
public static Vector operator /( Vector vector1 , Vector vector2 )
{ return new Vector ( vector1.X / vector2.X , vector1.Y / vector2.Y , vector1.Z / vector2.Z ); }
public static Vector operator *( Vector vector1 , Vector vector2 )
{ return new Vector ( vector1.X * vector2.X , vector1.Y * vector2.Y , vector1.Z * vector2.Z ); }
public static void operator ++( Vector vector )
{ vector.Z++; }
public static void operator --( Vector vector )
{ vector.Z--; }
#endregion

[/SPOILER]

Angle:
[SPOILER]

#region Properties
public float P;
public float Y;
public float R;
public float Pitch { get { return Pitch; } set { P = value; } }
public float Yaw { get { return Yaw; } set { Y = value; } }
public float Roll { get { return Roll; } set { R = value; } }
#endregion
#region Constructors
public Angle( )
{ P = 0; Y = 0; R = 0; }
public Angle( float pitch , float yaw )
{ P = pitch; Y = yaw; R = 0; }
public Angle( float pitch , float yaw , float roll )
{ P = pitch; Y = yaw; R = roll; }
#endregion
#region Methods
public Vector Forward( )
{
}
public Vector Right( )
{
}
public Vector Up( )
{
}
#endregion

[/SPOILER] Edited by DarkScience

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I didn't look at your code, but there seems to be a conceptual problem with what you are doing: XYZ describes a vector, while PYR describes a rotation. These are different things, and you can't convert one to another.

What are you really trying to do?

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I didn't look at your code, but there seems to be a conceptual problem with what you are doing: XYZ describes a vector, while PYR describes a rotation. These are different things, and you can't convert one to another.

What are you really trying to do?


You don't appear to understand the Vector/Angle model. It is possible and is done in just about every game out there. PYR can be converted to a normal which is a direction represented in XYZ and vice-versa.

Also i may of just figured it out. Ensuring consistency now ...
Never mind still don't have it .... Edited by DarkScience

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first set
[spoiler]

double A_P = math.DegreeToRadian ( P ); // 0 to 360
double A_Y = math.DegreeToRadian ( Y );// 0 to 360
double A_R = math.DegreeToRadian ( R );// 0 to 360

normal.X = ( Math.Sin ( A_Y ) );
normal.Y = ( Math.Cos ( A_Y ) );
normal.Z = ( Math.Tan ( A_P ) );
[/quote]

seems to give.

Angle: {P=0,Y=0,R=0}
Forward: {X=0,Y=1,Z=0}

Angle: {P=0,Y=90,R=0}
Forward: {X=1,Y=6.12303176911189E-17,Z=0}

Angle: {P=0,Y=180,R=0}
Forward: {X=1.22460635382238E-16,Y=-1,Z=0}

Angle: {P=0,Y=270,R=0}
Forward: {X=-1,Y=-1.83690953073357E-16,Z=0}

Angle: {P=0,Y=360,R=0}
Forward: {X=-2.44921270764475E-16,Y=1,Z=0}
[/quote]

Y seems to be correct at 0,180,360 but incorrect in between.
X seems to be correct at 0,90,270 but incorrect in between and oddly enough at 360.
[/spoiler]

second set
[spoiler]

double A_P = P; //math.DegreeToRadian ( P );
double A_Y = Y; //math.DegreeToRadian ( Y );
double A_R = R; //math.DegreeToRadian ( R );

normal.X = ( Math.Sin ( A_Y ) );
normal.Y = ( Math.Cos ( A_Y ) );
normal.Z = ( Math.Tan ( A_P ) );
[/quote]

seems to give

Angle: {P=0,Y=0,R=0}
Forward: {X=0,Y=1,Z=0}

Angle: {P=0,Y=90,R=0}
Forward: {X=0.893996663600558,Y=-0.44807361612917,Z=0}

Angle: {P=0,Y=180,R=0}
Forward: {X=-0.80115263573383,Y=-0.598460069057858,Z=0}

Angle: {P=0,Y=270,R=0}
Forward: {X=-0.176045946471211,Y=0.984381950632505,Z=0}

Angle: {P=0,Y=360,R=0}
Forward: {X=0.958915723414307,Y=-0.283691091486527,Z=0}
[/quote]

Y is correct at 0 and incorrect every where else.
X is correct at 0 and incorrect every where else.

though the values are -1 to 1 which is the correct format.

[/spoiler]

this is what im using to determine the accuracy of the values, they seem to slightly off in the second set though very close to what there suppose to be. Seems to increase in inaccuracy the larger the number.
http://www.mathsisfu...Cosine, Tangent Edited by DarkScience

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You don't appear to understand the Vector/Angle model.


I guess I can't help you, since I don't understand anything.

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[quote name='DarkScience' timestamp='1339437639' post='4948229']
You don't appear to understand the Vector/Angle model.


I guess I can't help you, since I don't understand anything.
[/quote]

Hoping you're not saying that in a sarcastic way in which your mad. I don't insult people in that way and wasn't implying anything by that comment.

Also I believe i will try a more manual way of doing what it is i desire. By converting 0 to 360 to -180 to 180 and applying some arithmetic's to convert it to x and y. Edited by DarkScience

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My comment was sarcastic, but I am not mad. The point of my first post is that you should probably try to explain how that vector XYZ expresses a rotation (i.e., how do you apply it to another vector?), so you can make things more clear to yourself and others. The procedure to convert PYR to the other format might become apparent once you express things precisely.

Also, giving some background about what you are trying to accomplish will generally get you much better help. Perhaps the solution to your problem would be trivial if you used some other representation for rotations, for example. Edited by alvaro

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I didn't look at your code, but there seems to be a conceptual problem with what you are doing: XYZ describes a vector, while PYR describes a rotation. These are different things, and you can't convert one to another.

What are you really trying to do?


Thought it was clear from the code i posted. But i shall explain further. Also Can't be done isn't asking for a better explanation nor is not reading all that i posted advised when your goal is to understand what i am after.

This is the object orientation in 3D space.
-X is Left, +X is Right
-Y is Backward , +Y is Forward
-Z is Down , +Z is Up

Now this is the view as in camera or object rotation.
-Pitch is Down, +Pitch is Up
-Yaw is Left, +Pitch is Right
-Roll is Roll Left, +Roll is Roll right // this isn't as important right now

The goal is to convert Pitch , Yaw , Roll to X , Y , Z and then back.
So Angle( 0 , 0 , 0 ) would be in XYZ ( 0 , 1 , 0 ).
So Angle( 0 , 90 , 0 ) would be in XYZ ( 1 , 0 , 0 ).
So Angle( 0 , 180 , 0 ) would be in XYZ ( 0 , -1 , 0 ).
So Angle( 0 , 270, 0 ) would be in XYZ ( -1 , -1 , 0 ).
So Angle( 0 , 360, 0 ) would be in XYZ ( 0 , 1 , 0 ). Edited by DarkScience

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You don't appear to understand the Vector/Angle model. It is possible and is done in just about every game out there. PYR can be converted to a normal which is a direction represented in XYZ and vice-versa.

Orientation and position are related but VERY different.

To represent position in 3D space you need spatial coordinates.
To represent orientation in 3D space you need a PYR triplet, or a 3x3 matrix, or a quaternion.


The first says where you are, the second defines your orientation (which can be used to determine what directions are up and forward).

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Alvaro is correct: a triplet of pitch, yaw and roll (Euler angles) represents a 3D orientation. An euclidean 3D vector can at most represent a direction in 3D space (plus a magnitude). That direction can be e.g. an axis of rotation, or a look-at direction, but it does not capture a full 3D orientation.

If representing an axis of rotation with a 3D euclidean vector, one needs to add in a single scalar (the angle of rotation about that axis) to make it a complete representation of a 3D orientation. This is commonly called an axis-angle representation of an orientation. If you are looking to convert an axis-angle representation to a 3D rotation matrix (and then to an Euler triplet), see e.g. MathGeoLib's float3x3::RotateAxisAngle function (boils down to Quat::SetFromAxisAngle).

If representing a look-at direction with a 3D euclidean vector, one needs to add in the concept of a 'up' vector (also called a 'world up' or a 'scene up' vector, a fixed vector specifying the upwards direction convention in the scene), or a single scalar 'roll' (being equivalent to above axis-angle) to make it a complete representation of a 3D orientation. This orientation however cannot have any roll, if the up vector is kept static. If you are looking how to turn a look-at direction vector into a 3D orientation, see e.g. MathGeoLib's float3x3::LookAt.

To convert a rotation matrix to pitch-yaw-roll components (Euler angles), see e.g. MathGeoLib's float3x3::ToEuler*** conversion functions.

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