I’m looking for a term that encompasses physical objects, people, processes. Basically everything from the real world as opposed to the digital. I have considered entity, but I am not sure, whether it fits the bill. Also I would need an attribute to differentiate it from digital things like software.
My context is general modelling. Intended usage would be: A model is a representation of …
In terms of objects and people, something that is in the so-called real world is corporeal:
1 : having, consisting of, or relating to a physical material body: such as
a : not spiritual
// … some few traces of a diviner nature which look out through his corporeal baseness …
— Robert Browning
b : not immaterial or intangible : SUBSTANTIAL
// corporeal property
A model is a representation of one or more corporeal objects.
But you may not be able to distinguish a virtual process from a real process. Since processes are ideas, they exist outside of anything physical (corporeal), and so have existence in both realms: the virtual and the material. (Note that material is a viable alternative to corporeal.)
In short, an idea that’s been expressed on a piece of paper, but not enacted anywhere, has just as much reality as an idea that’s expressed in a game, but not enacted anywhere. In fact, if the idea is actually enacted in a game, it may be thought of to actually be more real than the same idea simply written down on a piece of paper in the corporeal world.
I don’t think you’re going to be able to come up with a word that applies to processes (or ideas) in the same way as one that will apply to physical objects and beings. Discussion of that would be better suited to the Philosophy.SE site.