If a user uploads a clean .STEP file especially for CFD simulations of fan blades e.t.c, he experiences some bad quality surfaces in the viewer. If this .STEP file is opened in some CAD software, the geometry seems perfectly fine.
The following information will help:
The bad faces in the viewer are not part of the clean CAD model. These tessellation are integrated by SimScale in order to increase the viewer performance. If these perturbations are not added, a fine surface like the fan blade can take a long time to load in the viewer.
However, this does not effect the meshing and the simulation setup. If a mesh is created over this CAD model with right parameters, this tessellation cannot be seen and smooth layers are generated.