I have created what may turn into a nice macro which can generate "anatomically
correct" impact craters for a planet or moon by simply specifying the desired
diameter of the crater and it's longitude and latitude on the planet's surface.
 For the most part I am happy with the results but would like to add a few
enhancements before sharing it with the community. The macro currently handles
the situation of "older" craters being partially obliterated by later impacts
and appropriately sized craters will display features such as peak rings and
central peaks. The per crater parse time is not to bad and is the same
regardless of how large or small the desired crater is.

My first goal is to reproduce the craters on the moon and I have downloaded and
database of some 6000 craters to work with.  Obviously, this takes some time to
parse especially when the macro has to check for and then handle instances of
crater overlapping. But rendering of the craters as separate objects runs very
quickly afterwards.

The slowdown (and I mean SLOOOOOOOOOOOOWWWWWWWDDDDDOOOOWWNNNNN!!!!!!!!) Occures
when I have to merge these craters with the "uncratered" parent planet
(sphere).
The floor inside an impact crater is always lower than that of the original
surface outside of the crater this means I have to remove enough of the
original sphere's surface where the crater will "sit" so the inside of the
crater is below the surface it impacts on. Every time I do this by subtracting
the craters from the planet using a difference CSG, the render time goes from a
couple of min to literaly days (almost a week). If I just render the planet with
the needed "excavations" the render takes hours (2 to 3) but that is tolerable
compared to a week. It is when I try to unite the craters and the "excavated"
planet that render time becomes downright glacial.  I have tried this with both
union and merge with no change in the slowness of the render any ideas on how to
speed this up would be greatly appreciated.

Post a reply to this message