Plotting 3D discrete points

[Oren Spector]

Hello Octave users,

I am new to this mailing list, so forgive me if a similar question was
asked before. (By the way, is there a search ability in the mailing
list archives? I couldn't find one)

I have a set of points in 3D space in an Nx3 matrix, which I call
"bd". This set of points is a discrete representation of some region
boundary in 3D space.

I use plot3 in order to visualize this set. If I use plot3( bd( :, 1
), bd( :, 2 ), bd( :, 3 ) ) Octave connects the points in the order in
which they appear in the matrix. But, I want to plot the set as
discete points. I found that by using plot3( bd( :, 1 ), bd( :, 2 ),
bd( :, 3 ), '+' ) I get a discrete plot, but each point appears as a
'+' sign, which makes the plot cumbersome. How can I plot the set as
discrete point, where each point appears as a dot?

Since the boundary I'm plotting is a closed surface I wish to use
different colors to ease its viewing. I want something similar to a
topographic map, in which different values in the Z-axis are colored
differently. Is there a simple method of doing that in Octave?

Thank you for your help,
  Oren