What is the z-fighting in my deck frame?

[GeneDavis 156]

I used a room divider wall of zero thickness and air gap material to cut out a deck edge where a column pier runs through.  See the picture.

 

Two things are annoying.  The gap I want between deck and stone pier face is 1", and the room divider wall is preventing me from running the railing (three segments, ends and balustered middle) into the stone.  I think I'll just bite the bullet and make these railings as library symbols using Sketchup.

 

And what is with the z-fighting seen in the face of the framing rim board?

[robdyck 527]

Plan?

[GeneDavis 156]

I gave up on it and used a Sketchup-built symbol.

[misterwiley 48]

Usually the wall type for the railing will be a typical wall type like interior-4 or something. If that's the case there is probably a wall layer with drywall or paint that is causing the white material to display. I usually create a new wall type with opening no material that is the width of my railing to eliminate this. This is of course all a guess without the plan file to look at. Hope that helps.