Creating concrete explosion effect on hammer?

[Bazooks]

(can't find a better way to describe it)
It looks kind of like this:

(Without the metal reinforcement ofc)

So... how'd you do that in hammer?

 

[Dr. Orange]

I recommend using displacements for the deformed concrete.

 

[Pocket]

The most accurate way to do it would be to have somebody make you a model, like the one they use for the broken wall in ctf_sawmill. If your map is still in its early phases, some simple brushes manipulated into some semblance of a hole using the vertex editor should be enough to get the idea across for now.

 

[Bazooks]

I recommend using displacements for the deformed concrete.

The right one, in the picture.

 

[Idolon]

There's a lot of examples of this in Half Life 2. You should decompile those maps and see what they do. Sometimes it's models, other times brushwork and displacements.