.skp vs 3DS file size

Can anyone tell me why the .skp file format for identical items ends up being greater than its 3DS equivalent? Comparing a couple of items - the 3DS objects have 2.5 times (more of less) more polys yet the file size is around 20% of the .skp? It looks like both are textured so both carrying similar materials files. File%20size File%20size_1

Without knowing anything about the internals, the thing that leaps out at me is that the 3DS files and FBX files are zipped while the SketchUp file isn’t. And zipping involves compression.

So unless the “File Size” column is reporting the total size of the files in the .zip BEFORE they are zipped, you’re comparing apples to oranges.


Textures are not incorporated in a 3DS file but are put in a separate folder. If you have large textures, this would affect the model file size dramatically, but not disk usage in general. The number of polys in a 3DS is bigger than in a SKP file because the 3DS is triangulated and breaks faces with more than 3 edges down. Beware also of exporting the SketchUp edges - it creates additional thin 3D faces where the edges in SU are. Additionally, a SketchUp file has styles and scenes that a 3DS hasn’t.

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