After a few 2D projects I’m finally about to enter the 3D world. I stumbled across a few uncertenties when creating the models regarding scaling.
Do you create them already in about the right scale or correct them within Unity?
Are there any “good/bad” scales/sizes when creating the game world inside the Unity project?
Is there anything I should have in mind when adding Physics to the Models?
Thanks in advance!
You can always correct it in Unity, no problem there. Also remember that 1 3D “unit” e.g. when modelling with Blender, is about 1 meter.
From what I’ve learned in Unity tuts.
An Adult human character in most cases, should be at least/close to 2 meters tall. That would be the height of two Unity cubes. One cube put on top of the other. From what I’ve learned, it helps with Unity physics too. Use that as a reference and model everything else based on that if you desire.
Oh, in Blender, a Blender Cube object, is two meters in height, breadth, width etc. So if making a human character in Blender, use a blender cube as a height reference. Taa daa. 
Those are some tall humans 
Same thing I said, when I first read about it.
He! He!
Make life easy. You’ll almost always want to use a “real world scale”, something like 1 unit = 1 meter, which happens to be the default as far as Unity’s physics system is concerned.
Other scales work just fine as far as the tech is concerned, but they can be a pain in the bum as far as workflow is concerned.
Also, you want transforms to have a scale of (1,1,1) wherever possible in your scene, since that helps with batching. To help with that, remember that you can do a uniform scale on import to Unity. So if your modelling package outputs at a different scale to Unity (ie: it uses centimeters instead of meters or something) you’ll want to do the re-scaling in the import properties, not in the transform.
Thank you all for your replies,
now i have a good reference i can work with, awesome 
I noticed that someone recently liked my comment.
So to add to what I said years ago, a character doesn’t have to be exactly 2 meters, but you can use it as a reference, when making human characters for games. You can make taller characters close to 2 meters, or way shorter than that. If you want, read all of our comments above, for more info.