Re: [Closed REQ 5735]: Opacity

[daemon]

The opacity value is only used if you enable transparency.  (That's
possible only on the SGI, not on the X or Nextstep versions, which can't
handle transparency at all.)  Use the keyboard shortcut "aT", or
see the Materials panel, or attach "appearance { +transparent }" as a prefix
to the relevant objects, or send a GCL command like
  (merge-ap World { +transparent })

Note in any case that transparency isn't really handled properly; to
really approximate the appearance of semitransparent surfaces, we'd have
to draw them in some consistent order (back to front or front to back).
We don't do this.  Under some circumstances things look reasonable,
but often they don't.

For best results, only enable transparency on those objects where it's
needed.  Things look better if fully-opaque objects are drawn without
transparency enabled, since enabling it turns off hidden-surface removal.
It also helps if the transparent objects appear later in geomview's
object browser, i.e. if you load opaque objects first, then transparent ones.

(Or, within you have a composite object like a LIST, you might have some opaque
and some transparent components.  Put the transparent ones last, and give them
"appearance" prefixes to enable transparency on only those portions.)