Hello, so I was doing some terrain and trying to import it into Roblox Studios. Every time I import it, it turns out huge and resizing on Roblox Studios doesn’t help either, it makes it look weird.
So when you import it, it will say the mesh you are importing is very large, would you like to resize the mesh?
Oh it was that simple… I apologies.
It’s ok looool…
If that happens try move it.
If that doesn’t work uh try make different terrain.
Your normals are inverted. Enter edit mode in Blender and select every face of your mesh. Then press Shift+N to recalculate the normals.
Once you’ve done that, you can import back into Roblox and resize it how you’d like.
To add - Shift + N might not work depending on the version of your Blender.
Here I have a resource that can help you out with your Inverted Normals and recalculating them and it works with different versions of blender.
Tiny bit late to the topic, but it doesn’t seem there was a clear fix to your problem so I’ve provided you this link to be any resource to you.
Do this: Before you export
In 2.8 with Eevee, turn this ON so that you can detected if your normals are flipped or not.
With 2.79 it should work fine, well 2.79 is quite the common one people use.