hey all,
The problem with going on vacation is you miss all the excting thigs on
the list!
Re Color and terrain modeling:
Terrain modeling is ideally suited to subtractive modeling techniques
because there are very few undercuts or overhangs in the world (cliffs or
caves) and usually the topographic base sizes will have to be failry
large to show any level of vertical change. We have been builiding our
topographic model bases for 3 years with stacked layers cut with a 2 axis
laser cutter, by year end we will have a 4'x8' x 1'(z) mill to create
much larger and more detailed topograhies. We have never seriously
considered adative processes due to the cost for a model envelope of any
size. We did work with one client and sent them to Baxter labs (who we
found through the list) they did a great LOM model of a Carribean Island
that the client was looking at building a rocket launch site on. I have
a vague recollection that the LOM model cost arroud 6K for a 2' x 5' ish
model in monochrome. THis was then painted by hand. LOM was selected
mostly becasue of the very fine detail of all the sink holes, coral etc
on the island. Currently most to many topograhic bases are built by
tracing the contours by hand with a pantograph type router. If you do
not have good digital data it is actaully faster to do it this way for
many sites.
Color on terrrain is an interesting problem. We use projectors to
project color data on to the model. The distortion correction is very
complex but has been solved by cartographic companies for compositing
many arial photos into a single image. Basically, we ignore the
distortion for small models with small elevations and with large
elevations we re-register or do "manual" digital corrections based on
experince and reference points.
The application of color to an existing model seems very problematic.
Not being a robotics expert, it would seem to me that you would need at
least a wrist on 3 axis to use an ink jet head. The limitations between
size of the head and the resulting accuracy and level of detail it could
achiecve on finely detailed topography and the spped at which it could
cover the model would seem to linit the utility somewhat. The head would
have to be very small to fit into, over and arround detail or the
accuracy would be diminished by the distance between the head and the
part. Perhaps a combination of exsting techniques and digital masking
would work.
Best to all
Charles Overy
__________________________________________________
Laser Graphic Manufacturing - Precision Models
for Architecture and Development
800-448-8808 - cwho@vailmtn.net - 970 - 827 -5274
____________________________________________________
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