Graphics Reference
In-Depth Information
Next,
R θ v 2 e 2 R θ =
x e 23
y e 31
+
x e 23 +
y e 31 +
(s
z e 12 )v 2 e 2 (s
z e 12 )
=
v 2 (s e 2 +
x e 3
y e 123 +
z e 1 )(s
+
x e 23 +
y e 31 +
z e 12 )
= v 2 2 (xy sz) e 1 + s 2
z 2 e 2 +
2 (yz + sx) e 3 .
x 2
+ y 2
Substituting
s 2
y 2
x 2
z 2
+
=
1
we have
R θ v 2 e 2 R
v 2 2 (xy
sz) e 1 + 1
2 x 2
z 2 e 2 +
sx) e 3 .
θ =
+
2 (yz
+
Next,
R θ v 3 e 3 R θ =
z e 12 )
= v 3 (s e 3 x e 2 + y e 1 z e 123 )(s + x e 23 + y e 31 + z e 12 )
=
(s
x e 23
y e 31
z e 12 )v 3 e 3 (s
+
x e 23 +
y e 31 +
v 3 2 (xz
sx) e 2 + s 2
z 2 e 3 .
x 2
y 2
+
sy) e 1 +
2 (yz
+
Substituting
s 2
z 2
x 2
y 2
+
=
1
we have
R θ v 3 e 3 R θ = v 3 2 (xz sy) e 1 +
2 (yz sx) e 2 + 1
2 x 2
+ y 2 e 3 .
Therefore,
R θ vR θ =
R v 1 e 1 R
R v 2 e 2 R
R v 3 e 3 R
+
+
or as a matrix
v 1
v 2
v 3
2 (y 2
+ z 2 )
1
2 (xy sz)
2 (xz + sy)
v 1
v 2
v 3
=
2 (x 2
z 2 )
2 (xy
+
sz)
1
+
2 (yz
sx)
2 (x 2
y 2 )
2 (xz
sy)
2 (yz
+
sx)
1
+
which is the same matrix representing the quaternion triple qpq 1 .
The reader should not be put off by the above algebraic proof. It has been in-
cluded to demonstrate that bivector rotors behave just like quaternions and are rep-
resented by identical matrices.
You may wish to investigate the matrix for the reverse rotor triple R θ pR θ , which
you will discover is
=
v 1
v 2
v 3
2 (y 2
z 2 )
+
+
1
2 (xy
sz)
2 (xz
sy)
v 1
v 2
v 3
2 (x 2
z 2 )
2 (xy
sz)
1
+
2 (yz
+
sx)
2 (x 2
y 2 )
2 (xz
+
sy)
2 (yz
sx)
1
+
and is the transpose of the above matrix for R θ vR θ . Thus the matrices confirm that
Search WWH ::




Custom Search