Making a grate that a player can lift a cube/sphere through.
Years ago I created a level where I could lift an object like a cube through a wall with a grate texture. The object could not be pulled through the wall, but could be moved to a different location behind the wall. I did this first with a built in grate texture, then later with a custom wire cage texture. I'm trying to do this again, but can't find out how I did it in the first place. A major HD crash wiped out all my old Hammer created levels, so I can't look at the originals. Does anyone know how to make a grate-textured wall that is solid to players and objects, that you can portal through, and still pick up cubes or spheres through?
OK. I remembered how I figured it out last time. When you create a level using the PTI editor within Portal 2, the window/grate feature already behaved this way. So, I created a simple room with a grate wall and a cube, then exported it to a Hammer file. Opening this file up in Hammer allowed me to examine how they did it. Actually quite simple to do this. Start with a super thin block with a grating texture, then convert it to a Func_Brush. Set the Solidity setting to Never Solid. Then you create a Player_Clip Brush around it. Lastly, you copy the Player_Clip, and convert it to a Func_Clip_Vphysics. This creates a grate that you can't walk through, objects like cubes can't go through, but you can still pick up through the grate. Nothing like solving your own problems. 
Great you posted your answer Samot! 
Different types of tool clip textures (and entity-tied brushes) can also get the effect of blocking certain items you want.
Refer to this page for more info on tool textures.
https://developer.valvesoftware.com/wiki/Tool_textures