Hey!
So I’ve been playing around with the old .obj importer plugins and I’ve been running into the issue where it only imports one triangle/wedge from the subdivided square,
So basically I’m trying to save time by sculpting a plane in blender and then importing it’s obj data into roblox.
The plugin i’m using is SlenderTracker's .obj Importer - Roblox
And in blender, It looks like this
I have had this issue too. The main reason I find this to happen is when you have gaps or one sided faces. I would try to go into blender and turn the terrain into a more a box rather than a plane.