slab problem

[strat]

i want to eliminante the edge lines of the slab on my down floor  but retain the hole trace on the center , how this can happen ? No solution found on internet

[Patrick M]

the slab boundary and punched openings in the slab will show whenever the slab is visible. You can hide the slab in entirety, either layer, renovation status, design options or by story visibility.
if you want the slab to be visible, but not the opening in the slab, you can punch the opening with a solid element operation, then hide the operator. SEO extrusions are not generally projected to plan view.
there are probably 3-4 different solutions to this; it's the sort of graphic 'problem' I talk through with clients to find the right fit for all their needs.

...
at first glance, I'd say you should look at the slab settings, set it to show on home story only, and relink it to the floor above so you don't see the opening above. But there are likely other repercussions to that, that I may not be seeing from this one post.