We're trying to make things go progressively opaque and then transparent.
We're opacity mapping applying a simple flic to a material that goes from
pure white to pure black- other than the opacity map the material has a
simple color (green). We want a green object to appear on a background and
then smoothly disappear.
Everything works as expected, except during 10 frames in the mapped flic
when the flic is 100% black (=100% transparent object). For these rendered
frames, instead of seeing through the object, it becomes solid black. The
next frame after shows a 98% transparent object.
I suspect this is an easy one. What are we doing wrong?