When creating your own mesh or adding new mesh to an existing object, it sometimes happens that the mesh looks invisible when importing to Sims 4 Studio. This is due to so called “Backfaced Normals”. The part where your texture should be visible is turned inwards.
To turn it outwards we go back to Blender.
Turn on the “Face Orientation” view shown on the picture above. Your whole Sim turns now blue – or red. Red is everything that is turned inwards and we want to have that to be blue too.
Select all the red faces (I recommend to use the face selection) and then press Shift + N. This should make the red faces turn blue.
If nothing changes, open the little pop up and check and uncheck it until it gives you the intended result. Once everything is blue, import your fixed mesh into Sims 4 Studio.
Need a visual explanation? Here is the tutorial in a video:
