Bob Hughes wrote:
> 
> Think you meant to say vertical instead of horizontal as in hf aspects.
> Perpendicular to the plane of the heightfield in other words. And I
> believe you may be right about the unsmooth quality of such. Smoothing
> goes from one pixel square to the next *across* the face of the hf, so the
> vertical or perpendicular surfaces are always potentially a large distance
> from each other the sharper the edge is.
> Hmmm, and now that I've done said that... smoothing will go parallel to
> the plane of the hf at least.

  The biggest contributer to unsmooth text in a height field will most
likely come from using too small of an original image for the Hf object
itself.
  The program will create X amount of grids for the pixel count of the
image used in it's creation. If you try to make a smooth object with an
original image of say 200 x 50 you are not likely to get very smooth
results. If instead you original artwork was more on the order of say
800 x 200 for a string of text, and you kept it scaled reasonably small
in the scene file, it will indeed produce very straight and smooth walls.
  The reason for this is actually quite obvious. If you have ever seen
a 3D mesh model that had a very low triangle count you would have noticed
that they are genraly faceted, blocky, and non uniform in appearence.
The same model with a tringle count ten times greater will generaly be
much smoother, will have lost it's faceted and blocky appearence and
can be used in a much more flexible manner.
  Pov's HF object is just like those those two models we just discussed
because the HF object in Pov is nothing more than an internaly genrated
mesh of triangles. If you don't give it enough information in the form
of an image to build your object with it will fill in those missing links
with flat trianglar sections and you lose smoothness and quality as a
result. If you give it a lot to work with it can optimize the HF object
since it can fill in the curves with many more triangles than it's low
triangle count version would.
  I personaly have constucted some rather amazing curves and tall objects
using the HF object and it can do a lot as long as you remember to use
large source images when detail is important. For stuff like rocks and
patches of dirt smaller images are ok but if you want to make a shiny
chrome bumper for a car with an HF object think in terms of giants.


-- 
Ken Tyler

mailto://tylereng@pacbell.net

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