Unreliable Unity Scene Sizes? Driving me crazy.

Unity Engine
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1

I noticed when going through my unity scene sizes in build report log that some scenes were far bigger than others (AVG scene size of 100KB, the 5 outliers ranged from 0.6MB-1.9MB (1 SCENE EQUIVALENT TO 19 TIMES THE AVG SCENE SIZE!) , there was a total of 5 outliers. The scenes in my game are all generally the same amount of objects, its a basic 2d platform game (apart from scene 0 and 1). Having analyzing each object in the scenes and not figuring out why these certain levels were so high, I excluded the scenes from the build and then compared if the total level sizes had gone down. To my surprise, the high sized scenes that I removed had now passed onto the next scene in size…
Attached are screenshots of the data.

An example from the data, level1.unity was 1.5MB, I removed that level from the build and rebuilt, now level2.unity is 1.5MB (when it was previously 64KB…)

The total compressed size in first build including all high MB scenes for unity scenes:
Total compressed size 14.7 MB. Total uncompressed size 99.7 MB.
After building and excluding those high mb scenes (which was >5MB in total sizes compressed) for unity scenes:
Total compressed size 14.5 MB. Total uncompressed size 97.6 MB.

Only a .2MB difference, however I can see a larger difference in the actual apk/.aap.

Is this a bug with Unity itself? Is the scene sizes in build report just unreliable?

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2

Do you use prefabs in scenes? If you drag a huge chunk of scene out and make a prefab out of it, the scene size will go down by about the same amount of the prefab size. Are you taking that into account?

Also, another huge source of scene size is lighting information. Turn light baking off completely to see what fraction comes from it.

3

Yes I do use prefabs, the issue as highlighted above doesn’t seem the be the actual scene layout. Its a bug in unity…

4

I think Kurt’s point is that if Scene 1 and Scene 2 both use Prefab P, the first scene in which P is referenced will get the “credit” for P’s size on disk. But then if you remove Scene 1, now Scene 2 is the first scene to reference P, so Scene 2 now gets the “credit” for P’s size.

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