Graphics Reference
In-Depth Information
⎡
⎤
10
0
⎣
⎦
rotate
α
about the
x
-axis
R
α,x
=
0
c
α
−
s
α
0
s
α
c
α
⎡
⎤
c
β
0
s
β
01 0
⎣
⎦
rotate
β
about the
y
-axis
R
β,y
=
−
s
β
0
c
β
⎡
⎤
c
γ
−
s
γ
0
⎣
⎦
rotate
γ
about the
z
-axis
R
γ,z
=
s
γ
c
γ
0
0
0
1
where
c
α
=
sin
α
,etc.
Remember that the right-most transform is applied first and the left-most trans-
form last. In terms of angles, the sequence is always
α
,
β
,
γ
.
For each composite transform you can verify that when
α
cos
α
and
s
α
=
=
β
=
γ
=
0 the result
is the identity transform
I
.
We now examine the twelve combinations in turn.