How to give Eidolon Undersized Weapons Ability?

[Exploit]

I have a centaur-like eidolon which per Ultimate Magic should have:

Undersized Weapons (Ex)

Although a centaur is Large, its upper torso is the same size as that of a Medium humanoid. As a result, they wield weapons as if they were one size category smaller than their actual size (Medium for most centaurs).​

How do I add this trait to my eidolon in Hero Labs?

 

[Aaron]

Those Models aren't supposed to introduce new evolutions from what I understand. I think that might be an ad-hoc thing thrown in there.

If you want to, you could make an adjustment and add that to the eidolon. The eval script just has to assign the Helper.Undersized tag to the race, like so:

First 600

      doneif (field[pIsOn].value = 0)

      perform hero.findchild[BaseRace].assign[Helper.Undersized]