| utilities.3d {lattice} | R Documentation |
These are (related to) the default panel functions for cloud
and wireframe.
ltransform3dMatrix(screen, R.mat) ltransform3dto3d(x, R.mat, dist)
x |
x can be a numeric matrix with 3 rows for
ltransform3dto3d
|
screen |
list, as described in cloud |
R.mat |
4x4 transformation matrix in homogeneous coordinates |
dist |
controls transformation to account for perspective viewing |
ltransform3dMatrix and ltransform3dto3d are utility
functions to help in computation of projections. These functions are
used inside the panel functions for cloud and
wireframe. They may be useful in user-defined panel functions
as well.
The first function takes a list of the form of the screen
argument in cloud and wireframe and a R.mat, a
4x4 transformation matrix in homogeneous coordinates, to return a new
4x4 transformation matrix that is the result of applying R.mat
followed by the rotations in screen. The second function
applies a 4x4 transformation matrix in homogeneous coordinates to a
3xn matrix representing points in 3-D space, and optionally does some
perspective computations. (There has been no testing with non-trivial
transformation matrices, and my knowledge of the homogeneous
coordinate system is very limited, so there may be bugs here.)
Deepayan Sarkar deepayan@stat.wisc.edu