I think there may be a problem with the "lifecyle" of a exported shadow generator.
If i create the shadow generator with the exporter (good bias and filter settings) the shadows show up IF the Y position is high enough off the ground. But if close to ground ... no shadows.
If i create the shadows in the client scene.executeWhenReady the shadows are perfect... If i Console.log both shadows generators (the one created from unity exporter and the one manually created) they are the same. Its weird... Maybe something to do with "Where In The Scene Lifecycle" the shadow generator is being created of exported and the shadow generator info is in the .babyone scene file.
I am attaching a test .babylon file exported from unity... The shadow generator part of the .babylon looks fine. but even in sandbox. With none of my babylon enhancements, the .babylon on load... Show the sphere above the ground... Shadows enabled and physics enabled... The balls starts to drop but when it gets close to ground, the shadow disappears. Its gotta be something in the way way is reading the shadow generator information and instantiates the BABYLON.ShadowGenerator... or maybe WHEN is instantiates the BABYLON.ShadowGenerator.
Anyways take a look a the MiniGame.babylon file in SANDBOX