Difference of asset bundle

Hi, everyone.
When I use two PCs to build the same material to the asset bundles, I find that the two asset bundles are different. The two PCs belong to me and my colleague, and CPUs, graphic cards and other devices are all the same. We both use Unity 4.6.9p4. Following pictures are the differences, I wonder why they are different:


I’m sorry for that English is not my native language.

Well, the asset format as well as the assetbundle format are proprietary binary formats. You shouldn’t really care about the internal format. However, as you can see both seem to contain the same data, but the order of some assets seems to be different. Are you sure you created them exactly the same way? If you select the asset in a different order, they might appear in a different order in the bundle. Also keep in mind there might be minor differences which could be based on:

  • asset IDs which are usually randomly chosen
  • time / date
  • some kind of checksum (which would be different if the order is different)
  • offsets / length fields within the file which also are different when the order of some assets are different.

However since the exact format is not known we simply don’t know what exact causes the changes. As i said you shouldn’t really care about the exact binary format.