TheEuler angles are three angles introduced byLeonhard Euler to describe theorientation of arigid body with respect to a fixedcoordinate system.^[1]

They can also represent the orientation of a mobileframe of reference in physics or the orientation of a generalbasis in three dimensionallinear algebra.

Classic Euler angles usually take the inclination angle in such a way that zero degrees represent the vertical orientation. Alternative forms were later introduced byPeter Guthrie Tait andGeorge H. Bryan intended for use in aeronautics and engineering in which zero degrees represent the horizontal position.

Euler angles can be defined by elementalgeometry or by composition of rotations (i.e.chained rotations). The geometrical definition demonstrates that three consecutiveelemental rotations (rotations about the axes of acoordinate system) arealways sufficient to reach any target frame.

The three elemental rotations may beextrinsic (rotations about the axesxyz of the original coordinate system, which is assumed to remain motionless), orintrinsic (rotations about the axes of the rotating coordinate systemXYZ, solidary with the moving body, which changes its orientation with respect to the extrinsic frame after each elemental rotation).

In the sections below, an axis designation with a prime mark superscript (e.g.,z″) denotes the new axis after an elemental rotation.

Euler angles are typically denoted asα,β,γ, orψ,θ,φ. Different authors may use different sets of rotation axes to define Euler angles, or different names for the same angles. Therefore, any discussion employing Euler angles shouldalways be preceded by their definition.

Without considering the possibility of using two different conventions for the definition of the rotation axes (intrinsic or extrinsic), there exist twelve possible sequences of rotation axes, divided in two groups:

• Proper Euler angles(z-x-z,x-y-x,y-z-y,z-y-z,x-z-x,y-x-y)
• Tait–Bryan angles(x-y-z,y-z-x,z-x-y,x-z-y,z-y-x,y-x-z).

Tait–Bryan angles are also calledCardan angles;nautical angles;heading, elevation, and bank; oryaw, pitch, and roll. Sometimes, both kinds of sequences are called "Euler angles". In that case, the sequences of the first group are calledproper orclassic Euler angles.

The Euler angles are three angles introduced by Swiss mathematicianLeonhard Euler (1707–1783) to describe theorientation of arigid body with respect to a fixedcoordinate system.^[1]

The axes of the original frame are denoted asx,y,z and the axes of the rotated frame asX,Y,Z. Thegeometrical definition (sometimes referred to as static) begins by defining theline of nodes (N) as the intersection of the planesxy andXY (it can also be defined as the common perpendicular to the axesz andZ and then written as the vector productN =z ×Z). Using it, the threeEuler angles can be defined as follows:

• ${\displaystyle \alpha }$  (or${\displaystyle \phi }$ ) is the signed angle between thex axis and theN axis (x-convention – it could also be defined betweeny andN, calledy-convention).
• ${\displaystyle \beta }$  (or${\displaystyle \theta }$ ) is the angle between thez axis and theZ axis.
• ${\displaystyle \gamma }$  (or${\displaystyle \psi }$ ) is the signed angle between theN axis and theX axis (x-convention).

Euler angles between two reference frames are defined only if both frames have the samehandedness.

Intrinsic rotations are elemental rotations that occur about the axes of a coordinate systemXYZ attached to a moving body. Therefore, they change their orientation after each elemental rotation. TheXYZ system rotates, whilexyz is fixed. Starting withXYZ overlappingxyz, a composition of three intrinsic rotations can be used to reach any target orientation forXYZ.

Euler angles can be defined by intrinsic rotations. The rotated frameXYZ may be imagined to be initially aligned withxyz, before undergoing the three elemental rotations represented by Euler angles. Its successive orientations may be denoted as follows:

• x-y-z orx₀-y₀-z₀ (initial)
• x′-y′-z′ orx₁-y₁-z₁ (after first rotation)
• x″-y″-z″ orx₂-y₂-z₂ (after second rotation)
• X-Y-Z orx₃-y₃-z₃ (final)

For the above-listed sequence of rotations, theline of nodesN can be simply defined as the orientation ofX after the first elemental rotation. Hence,N can be simply denotedx′. Moreover, since the third elemental rotation occurs aboutZ, it does not change the orientation ofZ. HenceZ coincides withz″. This allows us to simplify the definition of the Euler angles as follows:

• α (orφ) represents a rotation around thez axis,
• β (orθ) represents a rotation around thex′ axis,
• γ (orψ) represents a rotation around thez″ axis.

Extrinsic rotations are elemental rotations that occur about the axes of the fixed coordinate systemxyz. TheXYZ system rotates, whilexyz is fixed. Starting withXYZ overlappingxyz, a composition of three extrinsic rotations can be used to reach any target orientation forXYZ. The Euler or Tait–Bryan angles (α,β,γ) are the amplitudes of these elemental rotations. For instance, the target orientation can be reached as follows (note the reversed order of Euler angle application):

• TheXYZ system rotates about thez axis byγ. TheX axis is now at angleγ with respect to thex axis.
• TheXYZ system rotates again, but this time about thex axis byβ. TheZ axis is now at angleβ with respect to thez axis.
• TheXYZ system rotates a third time, about thez axis again, by angleα.

In sum, the three elemental rotations occur aboutz,x andz. This sequence is often denotedz-x-z (or 3-1-3). Sets of rotation axes associated with both proper Euler angles and Tait–Bryan angles are commonly named using this notation (see above for the six possibilities for each).

If each step of the rotation acts on the rotating coordinate system XYZ, the rotation is intrinsic (Z-X'-Z'').Intrinsic rotation can also be denoted 3-1-3.

Angles are commonly defined according to theright-hand rule. Namely, they have positive values when they represent a rotation that appears clockwise when looking in the positive direction of the axis, and negative values when the rotation appears counter-clockwise. The opposite convention (left hand rule) is less frequently adopted.

About the ranges (usinginterval notation):

• forα andγ, the range is definedmodulo 2πradians. For instance, a valid range could be[−π, π].
• forβ, the range coversπ radians (but can not be said to be modulo π). For example, it could be[0, π] or[−π/2, π/2].

The anglesα,β andγ are uniquely determined except for the singular case that thexy and theXY planes are identical, i.e. when thez axis and theZ axis have the same or opposite directions. Indeed, if thez axis and theZ axis are the same,β = 0 and only (α + γ) is uniquely defined (not the individual values), and, similarly, if thez axis and theZ axis are opposite,β = π and only (α − γ) is uniquely defined (not the individual values). These ambiguities are known asgimbal lock in applications.

There are six possibilities of choosing the rotation axes for proper Euler angles. In all of them, the first and third rotation axes are the same. The six possible sequences are:

1. z₁-x′-z₂″ (intrinsic rotations) orz₂-x-z₁ (extrinsic rotations)
2. x₁-y′-x₂″ (intrinsic rotations) orx₂-y-x₁ (extrinsic rotations)
3. y₁-z′-y₂″ (intrinsic rotations) ory₂-z-y₁ (extrinsic rotations)
4. z₁-y′-z₂″ (intrinsic rotations) orz₂-y-z₁ (extrinsic rotations)
5. x₁-z′-x₂″ (intrinsic rotations) orx₂-z-x₁ (extrinsic rotations)
6. y₁-x′-y₂″ (intrinsic rotations) ory₂-x-y₁ (extrinsic rotations)

Precession,nutation, andintrinsic rotation are defined as the movements obtained by changing one of the Euler angles while leaving the other two constant. These motions are not all expressed in terms of the external frame, or all in terms of the co-moving rotated body frame, but in a mixture. They constitute amixed axes of rotation system – precession moves the line of nodes around the external axisz, nutation rotates around the line of nodesN, and intrinsic rotation is aroundZ, an axis fixed in the body that moves.

Note: If an object undergoes a certain change of orientation this can be described as a combination of precession, nutation, and internal rotation, but how much of each depends on what XYZ coordinate system one has chosen for the object.

As an example, consider atop. If we define the Z axis to be the symmetry axis of the top, then the top spinning around its own axis of symmetry corresponds to intrinsic rotation. It also rotates around its pivotal axis, with its center of mass orbiting the pivotal axis; this rotation is a precession. Finally, the top may wobble up and down (if it is not what is called asymmetric top); the change of inclination angle is nutation. The same example can be seen with the movements of the earth.

Though all three movements can be represented by rotation matrices, only precession can be expressed in general as a matrix in the basis of the space without dependencies on the other angles.

These movements also behave as a gimbal set. Given a set of frames, able to move each with respect to the former according to just one angle, like a gimbal, there will exist an external fixed frame, one final frame and two frames in the middle, which are called "intermediate frames". The two in the middle work as two gimbal rings that allow the last frame to reach any orientation in space.

The second type of formalism is calledTait–Bryan angles, after Scottish mathematical physicistPeter Guthrie Tait (1831–1901) and English applied mathematicianGeorge H. Bryan (1864–1928). It is the convention normally used for aerospace applications, so that zero degrees elevation represents the horizontal attitude. Tait–Bryan angles represent the orientation of the aircraft with respect to the world frame. When dealing with other vehicles, differentaxes conventions are possible.

The definitions and notations used for Tait–Bryan angles are similar to those described above for proper Euler angles (geometrical definition,intrinsic rotation definition,extrinsic rotation definition). The only difference is that Tait–Bryan angles represent rotations about three distinct axes (e.g.x-y-z, orx-y′-z″), while proper Euler angles use the same axis for both the first and third elemental rotations (e.g.,z-x-z, orz-x′-z″).

This implies a different definition for theline of nodes in the geometrical construction. In the proper Euler angles case it was defined as the intersection between two homologous Cartesian planes (parallel when Euler angles are zero; e.g.xy andXY). In the Tait–Bryan angles case, it is defined as the intersection of two non-homologous planes (perpendicular when Euler angles are zero; e.g.xy andYZ).

The three elemental rotations may occur either about the axes of the original coordinate system, which remains motionless (extrinsic rotations), or about the axes of the rotating coordinate system, which changes its orientation after each elemental rotation (intrinsic rotations).

There are six possibilities of choosing the rotation axes for Tait–Bryan angles. The six possible sequences are:

• x-y′-z″ (intrinsic rotations) orz-y-x (extrinsic rotations)
• y-z′-x″ (intrinsic rotations) orx-z-y (extrinsic rotations)
• z-x′-y″ (intrinsic rotations) ory-x-z (extrinsic rotations)
• x-z′-y″ (intrinsic rotations) ory-z-x (extrinsic rotations)
• z-y′-x″ (intrinsic rotations) orx-y-z (extrinsic rotations): the intrinsic rotations are known as: yaw, pitch and roll
• y-x′-z″ (intrinsic rotations) orz-x-y (extrinsic rotations)

Tait–Bryan convention is widely used in engineering with different purposes. There are severalaxes conventions in practice for choosing the mobile and fixed axes, and these conventions determine the signs of the angles. Therefore, signs must be studied in each case carefully.

The range for the anglesψ andφ covers 2π radians. Forθ the range coversπ radians.

These angles are normally taken as one in the external reference frame (heading,bearing), one in the intrinsic moving frame (bank) and one in a middle frame, representing anelevation or inclination with respect to the horizontal plane, which is equivalent to the line of nodes for this purpose.

For an aircraft, they can be obtained with three rotations around itsprincipal axes if done in the proper order and starting from a frame coincident with the reference frame.

• Ayaw will obtain the bearing,
• apitch will yield the elevation, and
• a roll gives the bank angle.

Therefore, in aerospace they are sometimes calledyaw, pitch, and roll. Notice that this will not work if the rotations are applied in any other order or if the airplane axes start in any position non-equivalent to the reference frame.

Tait–Bryan angles, followingz-y′-x″ (intrinsic rotations) convention, are also known asnautical angles, because they can be used to describe the orientation of a ship or aircraft, orCardan angles, after the Italian mathematician and physicistGerolamo Cardano, who first described in detail theCardan suspension and theCardan joint.

A common problem is to find the Euler angles of a given frame. The fastest way to get them is to write the three given vectors as columns of a matrix and compare it with the expression of the theoretical matrix (see later table of matrices). Hence the three Euler Angles can be calculated. Nevertheless, the same result can be reached avoiding matrix algebra and using only elemental geometry. Here we present the results for the two most commonly used conventions:ZXZ for proper Euler angles andZYX for Tait–Bryan. Notice that any other convention can be obtained just changing the name of the axes.

Assuming a frame withunit vectors (X,Y,Z) given by their coordinates as in the main diagram, it can be seen that:

${\displaystyle \cos (\beta )=Z_3.}$ 

And, since

${\displaystyle {\sin }^{2}x=1-{\cos }^{2}x,}$ 

for  we have

${\displaystyle \sin (\beta )=\sqrt{1-Z_3^2}.}$ 

As${\displaystyle Z_2}$  is the double projection of a unitary vector,

${\displaystyle \cos (\alpha )\cdot \sin (\beta )=-Z_2,}$ 

${\displaystyle \cos (\alpha )=-Z_2/\sqrt{1-Z_3^2}.}$ 

There is a similar construction for${\displaystyle Y_3}$ , projecting it first over the plane defined by the axisz and the line of nodes. As the angle between the planes is${\displaystyle \pi /2-\beta }$  and${\displaystyle \cos (\pi /2-\beta )=\sin (\beta )}$ , this leads to:

${\displaystyle \sin (\beta )\cdot \cos (\gamma )=Y_3,}$ 

${\displaystyle \cos (\gamma )=Y_3/\sqrt{1-Z_3^2},}$ 

and finally, using theinverse cosine function,

${\displaystyle \alpha =\arccos \left(-Z_2/\sqrt{1-Z_3^2}\right),}$ 

${\displaystyle \beta =\arccos \left(Z_3\right),}$ 

${\displaystyle \gamma =\arccos \left(Y_3/\sqrt{1-Z_3^2}\right).}$ 

Assuming a frame withunit vectors (X,Y,Z) given by their coordinates as in this new diagram (notice that the angle theta is negative), it can be seen that:

${\displaystyle \sin (\theta )=-X_3}$ 

As before,

${\displaystyle {\cos }^{2}x=1-{\sin }^{2}x,}$ 

for  we have

${\displaystyle \cos (\theta )=\sqrt{1-X_3^2}.}$ 

in a way analogous to the former one:

${\displaystyle \sin (\psi )=X_2/\sqrt{1-X_3^2}.}$ 

${\displaystyle \sin (\varphi )=Y_3/\sqrt{1-X_3^2}.}$ 

Looking for similar expressions to the former ones:

${\displaystyle \psi =\arcsin \left(X_2/\sqrt{1-X_3^2}\right),}$ 

${\displaystyle \theta =\arcsin (-X_3),}$ 

${\displaystyle \varphi =\arcsin \left(Y_3/\sqrt{1-X_3^2}\right).}$ 

Note that the inverse sine and cosine functions yield two possible values for the argument. In this geometrical description, only one of the solutions is valid. When Euler angles are defined as a sequence of rotations, all the solutions can be valid, but there will be only one inside the angle ranges. This is because the sequence of rotations to reach the target frame is not unique if the ranges are not previously defined.^[2]

For computational purposes, it may be useful to represent the angles usingatan2(y,x). For example, in the case of proper Euler angles:

${\displaystyle \alpha =\mathrm{atan2}(Z_1,-Z_2),}$ 

${\displaystyle \gamma =\mathrm{atan2}(X_3,Y_3).}$ 

Euler angles are one way to represent orientations. There are others, and it is possible to change to and from other conventions. Three parameters are always required to describe orientations in a3-dimensionalEuclidean space. They can be given in several ways, Euler angles being one of them; seecharts on SO(3) for others.

The most common orientation representations are therotation matrices, theaxis-angle and thequaternions, also known asEuler–Rodrigues parameters, which provideanother mechanism for representing 3D rotations. This is equivalent to the special unitary group description.

Expressing rotations in 3D as unit quaternions instead of matrices has some advantages:

• Concatenating rotations is computationally faster and numerically more stable.
• Extracting the angle and axis of rotation is simpler.
• Interpolation is more straightforward. See for exampleslerp.
• Quaternions do not suffer fromgimbal lock as Euler angles do.

Regardless, the rotation matrix calculation is the first step for obtaining the other two representations.

Any orientation can be achieved by composing three elemental rotations, starting from a known standard orientation. Equivalently, anyrotation matrixR can bedecomposed as a product of three elemental rotation matrices. For instance:$${\displaystyle R=X(\alpha )Y(\beta )Z(\gamma )}$$ is a rotation matrix that may be used to represent a composition ofextrinsic rotations about axesz,y,x, (in that order), or a composition ofintrinsic rotations about axesx-y′-z″ (in that order). However, both the definition of the elemental rotation matricesX,Y,Z, and their multiplication order depend on the choices taken by the user about the definition of both rotation matrices and Euler angles (see, for instance,Ambiguities in the definition of rotation matrices). Unfortunately, different sets of conventions are adopted by users in different contexts. The following table was built according to this set of conventions:

1. Each matrix is meant to operate by pre-multiplyingcolumn vectors$\left[\begin{array}{c}x\\ y\\ z\end{array}\right]$  (seeAmbiguities in the definition of rotation matrices)
2. Each matrix is meant to represent anactive rotation (the composing and composed matrices are supposed to act on the coordinates of vectors defined in the initial fixed reference frame and give as a result the coordinates of a rotated vector defined in the same reference frame).
3. Each matrix is meant to represent, primarily, a composition ofintrinsic rotations (around the axes of the rotating reference frame) and, secondarily, the composition of threeextrinsic rotations (which corresponds to the constructive evaluation of the R matrix by the multiplication of three truly elemental matrices, in reverse order).
4. Right handed reference frames are adopted, and theright hand rule is used to determine the sign of the anglesα,β,γ.

For the sake of simplicity, the following table of matrix products uses the following nomenclature:

1. X,Y,Z are the matrices representing the elemental rotations about the axesx,y,z of the fixed frame (e.g.,X_α represents a rotation aboutx by an angleα).
2. s andc represent sine and cosine (e.g.,s_α represents the sine ofα).

These tabular results are available in numerous textbooks.^[3] For each column the last row constitutes the most commonly used convention.

To change the formulas forpassive rotations (or find reverse active rotation), transpose the matrices (then each matrix transforms the initial coordinates of a vector remaining fixed to the coordinates of the same vector measured in the rotated reference system; same rotation axis, same angles, but now the coordinate system rotates, rather than the vector).

The following table contains formulas for anglesα,β andγ from elements of a rotation matrix${\displaystyle R}$ .^[4]

The Euler angles form achart on all ofSO(3), thespecial orthogonal group of rotations in 3D space. The chart is smooth except for a polar coordinate style singularity alongβ = 0. Seecharts on SO(3) for a more complete treatment.

The space of rotations is called in general "TheHypersphere of rotations", though this is a misnomer: the groupSpin(3) isisometric to the hypersphereS³, but the rotation space SO(3) is instead isometric to thereal projective spaceRP³ which is a 2-foldquotient space of the hypersphere. This 2-to-1 ambiguity is the mathematical origin ofspin in physics.

A similar three angle decomposition applies toSU(2), thespecial unitary group of rotations in complex 2D space, with the difference thatβ ranges from 0 to 2π. These are also called Euler angles.

TheHaar measure for SO(3) in Euler angles is given by the Hopf angle parametrisation of SO(3),${\displaystyle \text{d}V\propto \sin \beta \cdot \text{d}\alpha \cdot \text{d}\beta \cdot \text{d}\gamma }$ ,^[5] where${\displaystyle (\beta ,\alpha )}$  parametrise${\displaystyle S^2}$ , the space of rotation axes.

For example, to generate uniformly randomized orientations, letα andγ be uniform from 0 to 2π, letz be uniform from −1 to 1, and letβ = arccos(z).

Other properties of Euler angles and rotations in general can be found from thegeometric algebra, a higher level abstraction, in which the quaternions are an even subalgebra. The principal tool in geometric algebra is the rotor${\displaystyle \mathbf{R}=[\cos (\theta /2)-Iu\sin (\theta /2)]}$  where${\displaystyle \theta =}$ angle of rotation,${\displaystyle \mathbf{u}}$  is the rotation axis (unitary vector) and${\displaystyle \mathbf{I}}$  is the pseudoscalar (trivector in${\displaystyle {\mathbb{R}}^3}$ )

It is possible to define parameters analogous to the Euler angles in dimensions higher than three.^{[6][7][unreliable source?]} In four dimensions and above, the concept of "rotation about an axis" loses meaning and instead becomes "rotation in a plane." The number of Euler angles needed to represent the groupSO(n) isn(n − 1)/2, equal to the number of planes containing two distinct coordinate axes inn-dimensional Euclidean space.

InSO(4) a rotation matrixis defined by two unit quaternions, and therefore has six degrees of freedom, three from each quaternion.

Their main advantage over other orientation descriptions is that they are directly measurable from a gimbal mounted in a vehicle. As gyroscopes keep their rotation axis constant, angles measured in a gyro frame are equivalent to angles measured in the lab frame. Therefore, gyros are used to know the actual orientation of moving spacecraft, and Euler angles are directly measurable. Intrinsic rotation angle cannot be read from a single gimbal, so there has to be more than one gimbal in a spacecraft. Normally there are at least three for redundancy. There is also a relation to the well-knowngimbal lock problem ofmechanical engineering.^[8]

When studying rigid bodies in general, one calls thexyz systemspace coordinates, and theXYZ systembody coordinates. The space coordinates are treated as unmoving, while the body coordinates are considered embedded in the moving body. Calculations involvingacceleration,angular acceleration,angular velocity,angular momentum, andkinetic energy are often easiest in body coordinates, because then the moment of inertia tensor does not change in time. If one also diagonalizes the rigid body's moment of inertia tensor (with nine components, six of which are independent), then one has a set of coordinates (called the principal axes) in which the moment of inertia tensor has only three components.

The angular velocity of a rigid body takes asimple form using Euler angles in the moving frame. Also theEuler's rigid body equations are simpler because the inertia tensor is constant in that frame.

In materials science, crystallographictexture (or preferred orientation) can be described using Euler angles. In texture analysis, the Euler angles provide a mathematical depiction of the orientation of individual crystallites within a polycrystalline material, allowing for the quantitative description of the macroscopic material.^[10] The most common definition of the angles is due to Bunge and corresponds to theZXZ convention. It is important to note, however, that the application generally involves axis transformations of tensor quantities, i.e. passive rotations. Thus the matrix that corresponds to the Bunge Euler angles is the transpose of that shown in the table above.^[11]

Euler angles, normally in the Tait–Bryan convention, are also used inrobotics for speaking about the degrees of freedom of awrist. They are also used inelectronic stability control in a similar way.

Gun fire control systems require corrections to gun-order angles (bearing and elevation) to compensate for deck tilt (pitch and roll). In traditional systems, a stabilizing gyroscope with a vertical spin axis corrects for deck tilt, and stabilizes the optical sights and radar antenna. However, gun barrels point in a direction different from the line of sight to the target, to anticipate target movement and fall of the projectile due to gravity, among other factors. Gun mounts roll and pitch with the deck plane, but also require stabilization. Gun orders include angles computed from the vertical gyro data, and those computations involve Euler angles.

Euler angles are also used extensively in the quantum mechanics of angular momentum. In quantum mechanics, explicit descriptions of the representations of SO(3) are very important for calculations, and almost all the work has been done using Euler angles. In the early history of quantum mechanics, when physicists and chemists had a sharply negative reaction towards abstract group theoretic methods (called theGruppenpest), reliance on Euler angles was also essential for basic theoretical work.

Many mobile computing devices containaccelerometers which can determine these devices' Euler angles with respect to the earth's gravitational attraction. These are used in applications such as games,bubble level simulations, andkaleidoscopes.^{[citation needed]}

• 3D projection
• Rotation
• Axis-angle representation
• Conversion between quaternions and Euler angles
• Davenport chained rotations
• Euler's rotation theorem
• Gimbal lock
• Quaternion
• Quaternions and spatial rotation
• Rotation formalisms in three dimensions
• Spherical coordinate system

• Biedenharn, L. C.; Louck, J. D. (1981),Angular Momentum in Quantum Physics, Reading, MA:Addison–Wesley,ISBN 978-0-201-13507-7
• Goldstein, Herbert (1980),Classical Mechanics (2nd ed.), Reading, MA: Addison–Wesley,ISBN 978-0-201-02918-5
• Gray, Andrew (1918),A Treatise on Gyrostatics and Rotational Motion, London:Macmillan (published 2007),ISBN 978-1-4212-5592-7
• Rose, M. E. (1957),Elementary Theory of Angular Momentum, New York, NY:John Wiley & Sons (published 1995),ISBN 978-0-486-68480-2
• Symon, Keith (1971),Mechanics, Reading, MA: Addison-Wesley,ISBN 978-0-201-07392-8
• Landau, L.D.;Lifshitz, E. M. (1996),Mechanics (3rd ed.), Oxford: Butterworth-Heinemann,ISBN 978-0-7506-2896-9

• "Euler angles",Encyclopedia of Mathematics,EMS Press, 2001 [1994]
• Weisstein, Eric W."Euler Angles".MathWorld.
• David Eberly.Euler Angle Formulas, Geometric Tools
• An interactive tutorial on Euler angles available athttps://www.mecademic.com/en/how-is-orientation-in-space-represented-with-euler-angles
• EulerAngles – an iOS app for visualizing in 3D the three rotations associated with Euler angles
• Orientation Library – "orilib", a collection of routines for rotation / orientation manipulation, including special tools for crystal orientations
• Online tool to convert rotation matrices available atrotation converter (numerical conversion)
• Online tool to convert symbolic rotation matrices (dead, but still available from theWayback Machine)symbolic rotation converter
• Rotation, Reflection, and Frame Change: Orthogonal tensors in computational engineering mechanics, IOP Publishing
• Euler Angles, Quaternions, and Transformation Matrices for Space Shuttle Analysis, NASA