export fbx model from Unity2021.3.35f1 to Unity5.6.5f1

Hi I am currently trying to export my scene from Unity2021.3.35f1 to Unity5.6.5f1. I have tried export package, asset bundle, fbx exporter and export as obj but in all these methods have failed. Any advice will be aprreciated

You understand that downgrading a project or even just assets within a project to an earlier editor version is unsupported?

It may not even work. More so if the gap between editor versions is as large as 2021.3 to 5.6 - at least five years. The serialization format of assets is likely to have changed in a way that Unity 5 is unable to load that content.

But since you did not mention what “failed” means, would you elaborate? At which point does it fail? How does it fail? Any error messages?

Why are you trying to do this anyway? Wouldn’t it be better to move your content to a newer editor version? It’s even required for some platforms, specifically mobile and web, to build with one of the newer editor versions.

Like I just tried that thing and a Unity registery package named FBX Exporter worked but

like the scene had some terrain also as a ground and tree and bushes planted on that but the terrain and its properties didn’t exported? Do you know any alternatives?