Date: Jul 17, 1996 1:48 AM
Author: David Smith
Subject: Revealing HiddenSurfaces

Could someone help on this? Thanks.

I want to plot two things in a single 3D graph. One thing is just a
surface which I can do easily enough as ...

model = Plot3D[(x + y)/2,
{x,0,25},{y,0,25}, PlotPoints -> 2,
Shading -> False,
HiddenSurface -> False]

where I can see the hidden surface. Superimposed on this I wanted data points
(where the Œerror¹ distance between each data point and the model surface
is shown by a vertical line). I did this in two steps. First make the
error lines with the example set ...

data = Show[Graphics3D[{Line[{{0,1.97,0.98},{0,1.97,0.99}}],
Axes -> True]]

Finally plot everything together.

Show[data, model, Shading -> False]

The problem is that I¹m unable to make the model surface transparent so
that I can see the error lines of the data points behind the surface.
Unfortunately Graphics3D doesn¹t have a HiddenSurface option (Plot3D and
Show do). Is there some way of doing this (maybe converting data to some
other kind of graphics object)? This has been bugging me and I would
really appreciate some pointers. Thanks.