Three-dimensional Fill Type

This option exists because in the course of the 3D projection, portions
of the original image may be stretched to fit the new surface. Points of
an image that formerly were right next to each other, now may have a space
between them. This option generally determines what to do with the space
between the mapped dots. It is not used if you have selected a value for
RAY other than 0.

For an illustration, pick the second option "just draw the points", which
just maps points to corresponding points. Generally this will leave empty
space between many of the points. Therefore you can choose various
algorithms that "fill in" the space between the points in various ways.

Later, try the first option "make a surface grid." This option will make a
grid of the surface which is as many divisions in the original "y"
direction as was set in "coarse" in the first screen. It is very fast, and
can give you a good idea what the final relationship of parts of your
picture will look like.

Later, try the second option "connect the dots (wire frame)", then "surface
fills" - "colors interpolated" and "colors not interpolated", the general
favorites of the authors. Solid fill, while it reveals the pseudo-geology
under your pseudo-landscape, inevitably takes longer.

Later, try the light source fill types. These two algorithms allow you to
position the "sun" over your "landscape." Each pixel is colored according
to the angle the surface makes with an imaginary light source. You will be
asked to enter the three coordinates of the vector pointing toward the
light in a following parameter screen - see {Light Source Parameters}.

"Light source before transformation" uses the illumination direction without
transforming it. The light source is fixed relative to your computer screen.
If you generate a sequence of images with progressive rotation, the effect is
as if you and the light source are fixed and the object is rotating. Therefore
as the object rotates features of the object move in and out of the light.
This fill option was incorrect prior to version 16.1, and has been changed.

"Light source after transformation" applies the same transformation to both
the light direction and the object. Since both the light direction and the
object are transformed, if you generate a sequence of images with the rotation
progressively changed, the effect is as if the image and the light source
are fixed in relation to each other and you orbit around the image. The
illumination of features on the object is constant, but you see the object
from different angles. This fill option was correct in earlier Fractint
versions and has not been changed.

For ease of discussion we will refer to the following fill types by these
numbers:
    1 - surface grid
    2 - (default) - no fill at all - just draw the dots
    3 - wire frame - joins points with lines
    4 - surface fill - (colors interpolated)
    5 - surface fill - (interpolation turned off)
    6 - solid fill - draws lines from the "ground" up to the point
    7 - surface fill with light model - calculated before 3D transforms
    8 - surface fill with light model - calculated after 3D transforms

Types 4, 7, and 8 interpolate colors when filling, making a very smooth
fill if the palette is continuous. This may not be desirable if the
palette is not continuous. Type 5 is the same as type 4 with interpolation
turned off. You might want to use fill type 5, for example, to project
a .GIF photograph onto a sphere. With type 4, you might see the filled-in
points, since chances are the palette is not continuous; type 5 fills
those same points in with the colors of adjacent pixels. However, for most
fractal images, fill type 4 works better.

This screen is not available if you have selected a ray tracing option.