What impacts final build size.

When im making final build, are all assets avaible in unity editor put into the build increasing its size?

Or just those which are actually used?

And second question related to that: is size of unity/libriary/Metadata Folder( catalog) increasing size of final build?

 

For the most part it's just the files that are used. There are a few exceptions (eg a folder called "resources"). Below are the relevant sections of the manual including how to see which files have been included in a build.

https://docs.unity3d.com/Manual/ReducingFilesize.html
https://docs.unity3d.com/Manual/SpecialFolders.html

 

Thanks, i noticed today rate at which Metadata folder grew in my simple space shooter,after i added some assets and it concerned me.

 

I'm going to assume you're referring to the Metadata folder in the Library folder. The Library folder is just a local cache for Unity. When you create or import an asset (or delete the folder for that matter) Unity has to process the file before it can be used. Processed copies go into the Library folder and the original stays in the Asset folder.

Essentially it makes hitting the Play button (or building the project) a wait measured in seconds rather than one measured in minutes or hours (one of the projects I'm working on takes about 30 minutes to completely regenerate the Library folder but is playable within 5 to 10 seconds).

https://docs.unity3d.com/Manual/BehindtheScenes.html