m0p@k.cc.purdue.edu (S. Kulikowski) (02/23/89)
i have been working on my mac2 for some time now, and there are some
things that i have been needing. if you know what i need, please send
me email or (better yet) a binhexed file containing the stuff. i do not
have time to read this net, so email to my address direct, if you will.
3D WIRE-FRAME GRAPHS, INCOMPLETE DATA SETS
i am working with 3D data sets and i need to graph them in a wire-frame
contour graph. i have seen a lot of contour graphing on the mac2, but
all of them are engineering applications which are used to test functions.
with a function, you can generate a Z value for each and every X Y
location. my problem is that i am working with real data sets which are
most often incomplete-- there are not Z values for every X Y location.
indeed, i want to study the data acquisition process by generating
graphs as each data point is acquired, then animating the sequence to
see how the graphs grow.
the main problem is what to do with nonexistent data points.
ideally, a null value should appear in the data set (in stat packages,
that is usually a period with no digits), then the graphing utility
knows not to draw the wires from adjascent data points. like a screen
with holes punched in it. the contour graphing applications (that i
have) all require some value, so i have been giving them a 0.0 which
gives a false floor and untrue steep slopes to surrounding data points.
i almost found a solution with Super3D. it is cad package (i forget
who published it right now). it does not have a graphing utility, per
se, but it does read in ASCII files containing graphics primitives which
it will draw. unless someone can point me to a 3D wire frame grapher
which accepts incomplete data sets, i will have to write a program which
will output Super3D's primitives. that means my program will have to
handle all the tedious stuff of scale, labelling the axes, etc. if i
have to go to all this work, at least Super3D has realtime object
rotation, object fills, variable lighting, and animation built in for
viewing. that would be nice, but i would like to spare myself the work
if something suitable already exists.
stan
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