Transform Node's "center" field

Quote:

> ...

> it, and then modifying the translation, and center field parameters. However

> I still do not understand how the center field works.

The center field specifies the center of rotation. It has no effect on position

(since that is what the translation field is for). If you are conversant with

matrix formulations of transforms, this is taken directly from Carey&Bell

( http://www.*-*-*.com/ #Transform):

Given a 3-dimensional point P and Transform node, P is transformed into point P'

in its parent's

coordinate system by a series of intermediate transformations. In matrix

transformation notation, where C

(center), SR (scaleOrientation), T (translation), R (rotation), and S (scale)

are the equivalent

transformation matrices,

P' = T C R SR S -SR -C P

The following Transform node:

Transform {

center C

rotation R

scale S

scaleOrientation SR

translation T

children [...]

Quote:

}

is equivalent to the nested sequence of:

Transform {

translation T

children Transform {

translation C

children Transform {

rotation R

children Transform {

rotation SR

children Transform {

scale S

children Transform {

rotation -SR

children Transform {

translation -C

children [...]

Quote:

}}}}}}}

--

Chris Morley