#Metaballs
>>I've wanted a way to build a model of a cave system with all the
interconnecting passageways that I could fly/swim thru.
Why? Are you trying to create your own cave system or copy an
existing one? The real problem with copying is the enormous data
required from the servey. I've been down this passage, so to speak,
before. I've used lofted shapes. But, my purpose was to create a 3D
god-like view of the cave without the earth encasing it. I've done
this with Little River Cave. While not perfect, what I did is pretty
close to what's there.
Philosophy: It is my opinion that 3D technology should not attempt to
replace what is more accurately and easily described by actual video
of the same thing. If the purpose is to document what's there then
viewing the actual video will convey much more than a graphic
representation of the data with a whole lot less work. The use of 3D
display should only be used when it can enhance or improve or better
explain what is there and not be used just because the technology
exists. If the purpose is to create a fantasy cave from ones
imagination as in a VR cave diving game (hey! what a great idea) then
the development of this technology as a fly through the cave would
have a place.
In reality the caves of North Florida are predominately established
in major layers of the karst. This makes them horizontal systems at
one depth after an initial desent from the surface. eg. Peacock cave
60-70 ft. Little River @100ft. Devils Eye at 100ft. Madison Blue at
100 ft. Bonnet at 20 ft. Eagles Nest at 270 ft. etc. This makes for
a rather boreing 3D graphic, especially when done to scale. On the
other hand, 3D display would be an enhancement for the Peacock III
cave system where the branch from the main tunnel drops through a
restriction into a chamber where the floor of this room goes through
a bedding plane opening up to a new chamber (Hendley's Castle) that
drops to a depth of 200 ft. in a beautiful setting with a large
broken rock maze. It ends at another very tight restriction at 200
ft. and hasn't been pushed beyond this. Nearby, physically is the
"lower-lower room" of Orange Grove cave. I'm sure you've been in
the main cavern. Through the breakdown in the floor there is a tight
(side mount) passage that cork screws to a bedding plane restriction
at a depth of 130 ft. (same as the one in nearby Hendley's) Through
the bedding plane there is a circular torus shapped room that was
described by the late Sheck Exley as 180-200 ft. depth with further
passages going deeper. I have not been through this bedding plane. It
is a zero vis. 50 ft. restricted passage. Nobody has ever connected
the Castle with the Lower-Lower room of Orange Grove Cave. A precise
survey in 3D might be the way to help locate the connection if it
exists.
Mark Miers had developed a coordinate conversion IPAS to assist me in
the transfer of survey data to 3DS data to create the actual
geometry. I haven't had the time to do any further work in this area
but this does look promising as opposed to manually scaling the data
in 3DS. You may wish to try this as opposed to the Blob modeler. If
you need some survey data just holler. You could try it on the
'Castle' data for me.