The answer to your question is quite simple, but might also be hard to understand whenever you’re not used to what is actually a “3d meshes”.
First, there is a major difference between your “terrain” and what you’re making inside any 3d software like Blender or 3ds Max. A terrain is a pre-made meshes that incorporate multiple features that are available a software like Blender, but without you doing anything to get them.
First, there’s the UVs. I’m not talking about some kind of sun-like component.
UVs are the “mapping coordinate” for the materials. Materials are the “bungle” that count every textures you put on a meshes. There can only be one material per meshes, thought a material can contain sub-materials. Textures can be in grayscale, RGB and even on Alpha channels.
There textures you’re painting on your terrain is actually a complex scripting that make many action in your stead :
First, it generate an UVs mapping of the terrain. Then it allow your to link materials which include textures to the meshes that is the terrain. Then, once you start “painting”, it generate an alpha-based map that allow transparency on the areas which aren’t “used” by the textures on different "layers. Every textures you put on your terrain generate an additional layer to the terrain mapping. Even through the mapping would normally be hard for any hardware, it automatically generating a finished texture which doesn’t include layers which is what you’re seeing being rendered. (The layers are generated and managed in the background… then they are “collapsed” on every changes and a the old “map” is changed to the new. The map is a lighter and optimized version of the layered hidden version.)
In a 3D software like Blender, you first need to set your UVs correctly. Without UVs, no texture will stick correctly to the planes of the meshes. The reason why the textures gets weirds when you stretch things is normal because the Uvs coordinate do NOT follow the changes on the vertex coordinates of its parented meshes. While the UVs and the Meshes share the same “naming” and uses of vertex and faces (triangles and squares), they are not the same on the management.
After the UVs are set, IF you need to stretch a part of your meshes, you only got one choices :
First is you plan ahead and, if you really have to change part, you restart. Officially, that’s the professional way of doing it as real pros plan far ahead before doing anything.
If you were using (and understanding) either Maya or 3Ds Max, a 2nd option would be available (which is an option to “preserve UVs” whenever you do minor fixes to a meshes. Blender is limited to a basic “UV correction” which only with with edge sliding.
Does the terrain made in Blender also have this blurry texture if exported and then viewed in Unity?
– Cherno