Simple rendering issues not resolved.

[LarryO]

Why has it been so difficult to stop these lines from occurring?
Over the years of VW development no repeatable technique nor application fix has emerged to ensure a predictable outcome for this problem.
Aside from tedious masking techniques which require repeatedly scanning viewports after adjustments to 3d objects.

This is a simple Wide Flange beam with subtract solids performed to create the round holes shown and remove a portion (cope) of the top flange.

Doesn't matter if the subtraction extrudes have three circles or one or if all the subtractions are separate operations or conducted as a single one in this instance.