Hi there!

Somehow I got the impression that the brief list of changes btw. 
versions 3.5 and 3.6. on http://www.povray.org/download/features/ might 
possibly be not too exhaustive...

OK, here's what I observerd: I am using POV-Ray for Windows as external 
rendere for some kinda Myst-style 3D adventure game experiment. To this 
end, I created a landscape based on a height field which uses the agate 
pattern as underlying function (actually I more or less copied the code 
from the scenes/advanced/landscape.pov demo file). I also randomly 
placed a bunch of ellipsoids ("pebbles") onto the landscape. The 
pebbles' x- and z-coordinates are created randomly, and the 
corresponding y-coordinates are calculated by using the trace() function 
in order to determine the height field's actual height at the pebbles' 
x- and z-positions. To circumvent the need for going through the 
time-consuming pebble creation process over and over again, I calculated 
the pebble positions only once and stored them into an include file.

Now after switching from version 3.5 to 3.6 the pebbles suddenly began 
to hover over the ground! Looks sort of mystic, but that's not what I 
actually intended... ;-)

When re-running the pebble position calculation under 3.6, everything is 
fine again -- the pebble's y-coordinates, however, really have changed 
when compared to the include file created with 3.5!

So does anyone know what might be the reason for the observed 
discrepancy? A change in how the agate function gets calculated? How 
height fields get smoothed? Or how the trace function determines 
intersections?

I wouldn't mind sticking with version 3.5 for now, it's just for the 
sake of curiousity...

Thanks for any comments --

	Torsten

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