no pop on certain part of object; huh?

[Dune]

I encountered a problem populating on an object. An integral part of the (separated ground) object just didn't get any instances. And not because the normal of that particular strip of polys was upside down, or the population size was inadequate.
Has anyone encountered this, and what might be the problem?

I had to resort to using a floating card in that particular (yellow circled) area, to grow an extra pop of flowers on, so it's solved, but still puzzling.

[sboerner]

I've run into that in areas that occur beneath upper projections. (Seems the pop assigns positions from a top-down POV, and intervening parts of the mesh can cast "shadows.") It's hard to tell here but maybe part of the roof/eaves is blocking that area.

Nice project btw.

[Dune]

Can't be that as it's next to eachother. Unfortunately. But I could try a slight angle in the pop, just to check it out. Thanks Steve! It's nice indeed.