Mathack not visible through the walls?

I haven't played for a long time in TF2. I've noticed colored models are not visible through the wall. Mathack works and I see colored models. But only when they are visible. I can't see models behind the wall. What happened? I tryed few different mathacks

This is probably due to the server(s) using sv_pure 1/2.
Mathacks only work properly on servers with sv_pure 0, to check, type "sv_pure" into the console.