Parts of my Mesh not Showing

Hello, I have recently been learning how to use blender, when I made this mountain it looks completely right in Blender. But when I imported (Fbx file) it into roblox studio, some parts were showing but when I turned my camera around some parts wouldn’t show while some did. Could anybody help me solve this problem?

How it looks in blender,
Screenshot 2020-04-03 at 10.08.54 *

And how it looks in Roblox Studio,

Screenshot 2020-04-03 at 10.08.16

Thank you for helping me!


In blender go into edit mode-> select all verts-> Shift+N (This fixes inside out faces which causes the problem) and then import the mesh again


In blender all models have double faces to see the actual face you must open the options and check the Backface Culling setting :

And you will notice that some faces disappeared it is because the face is inverted
To fix this you go in model editor mode, select all inverted faces and flip the normals

After that, you can export the model and import it on Roblox


In the future please use the search bar as there are already been some topics about this.

sorry to bump this, however i did this and instead of removing it all, new spots popped up and the previous spots were fixxed. do i have to manually fix this?