As a result of frustration on my part and inspiration on
Bill DeWitt's part (see "Rotate list" in povray.general),
I've come up with a set of macros that allow easy
rotation of objects in arbitrary axis order.

The macros return a single rotation vector that will result
in the same object rotation as though you had used
multiple rotation statements.

I can turn this code:

object { MyObject
  rotate 30*y
  rotate <40,0,60>
}

Into this:

object { MyObject
  rotate yxz(30,40,60)
}

Admittedly, here it's not that big of an improvement.

However, when I wanted to store a rotation vector in a
variable to use later, it was prohibitively difficult to have
the rotations done in any order except x then y then z.

Now I can do this:

#declare ROT = yzx(20,30,40); // 20*y, 30*z then 40*z
//   ROT is now < 33.856616, -2.292945, 35.467006>
object { MyObject rotate ROT }


I mainly did these for myself, but thought others might
like them, too.  I hope some of you can find some use
out of these.

--
Tom Bates

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