Games have a lot of this 'fakery' type stuff going on anyway. In my current project, pretty much everything is going to be based on sphere colliders. Most games simply use a few primitive colliders that can approximate the shape of the object. Another part is the simple amount of triangles involved. Part of that is the convex/concave issue(look it up). There are certain requirements for using meshes as colliders, and many games in fact avoid the issue completely. I can vouch that the issue has nothing to do with the modeller you are using, but rather what you are attempting to do with the model. I have searched YouTube, Reddit Forums, and Unity Forums. If there is any possible way to get Blender to work properly that would be great. If I have to go with buying Lightwave It will slow me down dramatically. Does Unity no longer support Blender anymore? The only other modeling program I can purchase is the new Lightwave for $995.00 USD. I don't know if the model will actually fall through the terrain or not but when I fly my sphere into the model, it does have the collision. The model then has collision but gravity does not work. I have to click the Kinematic checkbox which turns off the gravity to the object. When I had a RigidBody to it, Unity throws an error saying that non-Kinematic mesh not supported since Unity 5. Then Imported the model in Unity 2018.3.0f2 and click on the model and clicked on Generate Collision. I have set the transforms to 0 on the X, Y, and Z. I have created a simple test model in Blender 2.79b and 2.8 Beta.