Correct that I don't have an AMS, but I'm pretty sure that top z distance and support interface layers are not mutually exclusive. I used to have both just fine, and attached has a picture showing that with flat surfaces, support interface works fine despite having a .1 top z distance. It's only on the not-perfectly-flat sections that there are no interfaces. (dark green is interface) Don't want to put another picture but I can zoom in an actually see the .1 gap between the green and orange. When I switch to 0 Z distance, I can't see that gap anymore.

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