My problem is probably really simple, but I need the model height of an entity/creature.

BoundingBoxes usually are smaller than the creature actually is (for example the chicken bounding box does not contain most of it's head - or the Squid's BB does not contain it's tentacles).

I tried to find a method which can give this to me but had no success. Maybe one of you can help me out.

 

Thanks in advance

There is no way to know.

 

For example, with squids, if you included the tentacles, would that be while they are close in against each other, or when they're spread out? Both? Animated along with the visuals?

.In a game like Minecraft, the mismatch between the visuals and the actual bounding boxes is part of the charm of the game. There are no exact hit boxes, and parts of models can overlap the nearby blocks or other entities. It is not meant to be super realistic.

 

If you really have a need for this, then for the vanilla entities you'd have to figure out the mismatch yourself and perhaps handle cases like Draco mentions where you know the model might be changing size. For example, a child entity is scaled down.

 

Basically I think for known entities it is possible to get pretty close, but just takes a bit of work and trial and error to get it the way you like it. But I don't think there is a generic way (like if you want it to work for other mod's entities). Or to be more precise, it would be a very advanced thing to do to inspect the models and figure it out generically.