I drone-scanned an area and created an obj from that scan, I imported it to Blender and used the smooth tool in sculpt mode to smooth the mesh where it was a bit jagged. Then I added textures and trees etc. When I was finished with the project I packed the resources (and moved it to an external HD). Today I needed to work on the project again, but when I opened it the areas that I had smoothed looked jagged again, but the mesh was smooth. It looks good in sculpt mode, but not in object mode etc. or when rendered. See attached images.
Does anyone know the reason for this, and how to solve it? All help appreciated.