From: dudley@matt.ksu.ksu.edu (D U D L E Y)
Newsgroups: comp.graphics.animation
Subject: Re: Trouble with POV animation/texturing
Date: 11 Jan 1993 15:43:52 -0600
Organization: Kansas State University
NNTP-Posting-Host: matt.ksu.ksu.edu

sjm@miles.com (Scott Mark) writes:

>I have been thinking about doing animations with POV, but it seems that
>the texture I'm using (DMFWood4) shifts when I move my camera!

From the documentation:

#       When animating objects with solid textures, the textures
#       must move with the object, i.e. apply the same rotate or
#       translate functions to the texture as to the object itself.
#       This is now done automatically if the transformations are
#       placed _after_ the texture block. Example:
#
#       object {
#         shape { ... }
#         texture { ... }
#         scale < 1 2 3 >
#       }
#
#       Will scale the shape and texture by the same amount.
#
#       object {
#         shape { ... }
#         scale < 1 2 3 >
#         texture { ... }
#       }
#
#       Will scale the shape, but not the texture.

Other things to keep in mind when creating several images for an
animation: (again, from the documentation)

#       Textures and Animation
#       If you are doing animation, you should specify all object
#       transformations after the texture transformations so the
#       texture "follows" or "sticks to" the object through 3-D
#       space. For example,
#
#       object {
#          shape {}   // Shape description
#          texture {} // Texture description
#          scale     // transform after shape & texture
#          rotate    // transform after shape & texture
#          translate // transform after shape & texture
#       }
#
#       As in:
#
#       object{
#          box {<-1 -1 -1> <1 1 1>} // Box shape centered on zero
#          texture {
#             agate
#             phong 1
#             scale <1.3 2 1.3> // scale texture to the
#                               // untransformed shape
#             rotate <30 0 0>   // rotate texture to the
#                               // untransformed shape
#          }
#          scale <3 3 3> // scale *both* sphere & texture
#          rotate <0 40 0> // rotate *both* sphere & texture
#          translate <1 5 5> // Move box & texture to final
#                            // position
#       }
#
#       If the transformations are done after the shape and before
#       the texture, the texture will not "stick to" the shape. In
#       an animation, this will look like the texture is constantly
#       moving on the moving shape. What is actually happening is
#       that the shape is moving and the texture is not, so the
#       texture on the shape changes whenever the shape is scaled,
#       rotated, or translated. This can be an interesting effect,
#       but is not desirable for most animations.

and

#         Random Dither
#       The floating-point value given immediately following the
#       texture keyword is an optional "texture randomness" value,
#       which causes a minor random scattering of calculated color
#       values and produces a sort of "dithered" appearance. This is
#       used by artists to minimize banding and to provide a more
#       chaotic, uneven look to a texture. Values are generally kept
#       quite small, like .05. This feature is different from
#       turbulence in that textures using it will look slightly
#       different each time they are rendered.
#
#       NOTE: This should not be used when rendering animations.
#       This is the only truly random feature in POV-Ray, and will
#       produce an annoying flicker of flying pixels on any textures
#       animated with a "randomness" value used.

and

#       WARNING: Image files created on with different executables
#       on the same or different computers may not look exactly the
#       same due to different random number generators used in some
#       textures. If you need to merge image files from different
#       computers contact the authors for more info.

Hope that helps.

-- 
                                                    John "Dudley" Hunkins
                                                  dudley@matt.ksu.ksu.edu
Newsgroups: comp.graphics.animation