I think I see the problem. You need the same randomised material on the 3 segments that make up the glass panel, but the Material operator assigns a new random id for each individual segment. Unfortunately this is a limitation of this operator but there are a few workarounds.
In the attached file I've included a style that uses the Random Number
parameter to generate a new material id only on each x spline section. This is then attached to the Material
operator's exported From
As all segments in a compose operator attached to an evenly input will take the ID of the preceding spline section, there's also a Conditional
operator that places a glass end as the first segment in each section.
As for using element IDs, if your polycount is not too high and you don't mind losing instancing support, then you can force welding by turning on Vertex Weld
in the Style
rollout, and then turning off Use Instancing Engine
, from the Display
rollout. I've attached an example to illustrate this as well.
I hope that helps, please let me know if you have further questions.