colors for show_interior_samples.py

[jstraub]

coloring for positive and negative samples

[tschmidt23]

Super cool! So I guess green is near the surface, blue outside and red inside?

Two quick thoughts:

• This no longer shows the internal samples so should perhaps be accompanied by a name change?
• This is definitely useful but I think the old implementation which shows only interior samples is also useful for different reasons. Do you think we should make this more flexible with a command line argument or button on a panel? Another useful feature might be to generalize the old "show everything with SDF val <= 0" rule to a flexible level set band where you can set the minimum and maximum SDF values to display, which would allow inspection of density at different distance from the surface.