Also, why is it defined in meters?
Hi @glorincz!
First of all I would appreciate if you put your questions into one post the next time, keeps things ordered and compact 
To quote @jprobst from this post here: Mesh Creation Input Questions - #2 by jousefm
“The help text is again incorrect. The hex-dominant (CFD) mesher has all lengths given in the unit of the project (i.e. meters in your case). We convert this in the back-end to a refinement level. The help text is outdated and we need to fix it.”
Best,
Jousef
Noted, thank you!
I still don’t understand though it’s the length of what exactly? It does say ‘min length’ and ‘max length’ in meters.
Hi @glorincz!
It is not a length but the refinement levels. All refinements are referred to the background or base mesh.
P.S.: Please let me confirm that a bit later. It might be that it takes the actual length of the element in order to have a reference for the refinement level. Will keep you up-to-date about this and the description 
Best,
Jousef
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