In-place walls showing transparent in all 3d views

[L.S.]

On Revit Lt 2020 my in-place walls are see-through in all 3d views. I don't want them to be. All other elements are not transparent, just the in-place walls. I imagine there must be a setting that did that. How can I fix it? Thanks.

[barthbradley · Accepted solution]

Could be any number of reasons. Maybe you are in Wireframe Mode. Maybe you assigned the wrong Material. Maybe you modeled it as a Mass and it's using the Default Mass Material.  

Can you post some illustrations or the file itself?  

[L.S.]

Thank you. The problem was the material. I had not assigned one, so it was whatever was already there.