volume command does not work on submodel specs (multiple contour levels)

[Elaine Meng]

If multiple contour levels are shown for a single volume model, using a submodel specification in the volume command to change only one of the isosurfaces does not work, e.g.

volume #1.1 color pink

...gives error message "No volumes specified" because #1.1, 1.2 etc. submodels of volume model #1 are surface models.

[Tom Goddard]

To change the color of a specific volume #1 surface the command "color #1.1 pink" will work. Oops, just saw that volume viewer does not see that color change and reverts to the old color. Fixed that. Also made the color command work on volume image submodels.

[Tom Goddard]

It would be nice if the volume command could take surface and image submodels, for example "volume #1.1 color pink" where #1 is a volume model and #1.1 is a volume surface. But there are several volume command options that might apply just to one surface, such as "style mesh", "enclosedVolume 1200", "level .5", "show", "hide". There are other options like "surfaceSmoothing", "capFaces", or "meshLightning" that cannot be applied to a single surface but act on all surfaces -- the user would need to be warned about that. And there are options that just apply to image submodels such as "blendOnGpu", or "projectionMode". If the volume command handles surface submodel specifiers it should also handle image submodel specifiers.

Enhancing the volume command to act specifcally on submodels of a volume instead of on the entire volume is a good bit of work. It does not seem like a high priority.