I’m trying to apply a megascan texture to a mesh i imported from blender through datasmith. The texture loads fine on UE4 created planes but on the imported mesh it does not load properly (as seen on the picture below).
Hard to tell. Can you check / share the UV for the wall mesh? And did you use the default Megascan material coming with the Importer - or only the textures combined with your own material?
The mesh had an alternative UV that came with it during the import from blender that made it read the material incorrectly. I simply deleted that UV so that the material would read from the UV as seen above. This solved the problem!
Because of the “size” of your UV map. For further informations and how to fix that do some research for UV Map Size or Texel Density.
For a quick fix you can create a Material Instance from your already existing Material and then increaset he UV Tiling by multiplying your Texture Coordinates or you try to setup a Material that uses World Aligned Coordinates (especially if you’re realizing an ArchViz project, the World Aligned Materials will come in handy).
The alternative UV most likely was for the lightmap. The lightmap UVs can not overlap and need to be all within that square. You can see it in your image.
The primary ID 0 will be used to scale the material correctly on the mesh. For walls or floors it is best to use box mapping (not sure what the name in Blender for it is). Megascan textures are often 1 m x 1 m or 2 m x 2 m in size and that is how you need to scale the UVs on your wall.
To know how UVs work is quite essential if you want to make anything ArchViz and realistic looking.