I don't know if there is any way to do this, but I want to basically sort a bunch of entities by their various surface properties. example: a device fires a certain output only if the object has a surfaceproperty of metal, flesh, or dirt, but nothing else. If there isn't a way to do this, then I could settle for making lots of filters, but if there is a filter for the surfaceproperties of a physics object, that would be much easier.

EDIT: fixed title

EDIT -

Where are these entities coming from? (Are they spawned dynamically in the map?)

Not really, most of the entities are pre-existing, but I'm planning to use this as a dynamic tool that can be placed down in a map similarly to a pti item, where only a few changes are needed to make it work with the map. If it isn't actually possible, it isn't a monster problem.

Ah, I see. How about this? Whenever a glass cube or a wooden cube or whatever is created, give it a classname with AddOutput (e.g. box > AddOutput > classname prop_weighted_cube_wood). Now you can filter by classname for the individual types, and detect all boxes by filtering for prop_weighted_cube*.

That's so cool. I never new that was possible.

Nice, that would probably work. I'll see if this element is still worth worth pursuing.