I'm working on a cube in Blender. I just deleted one of the faces (the top face) of the cube and added solidify to avoid non manifold edges.
In this case, when I check the design it shows that the bottom face is an overhang face (shown with yellow color). However, if I change the overhang parameter in 3D printing tool box from 45 to 90° and then check the model, it doesn't show any overhang faces and it seems that everything is okay. I don't think increasing the overhang parameter could be a good idea. However, this is my first time that I'm trying to design a model for 3D printing. Can this model with the overhang parameter equal to 90° be printed using a 3D printer? How can I fix the overhang problem in this simple model.
Today I tested another simple model. I used a fill circle and added solidify to the model. Although the model is really simple, check the model shows the same as the previous design - the bottom face is an overhang face. It seems that adding solidify to a shape leads to this problem. I don't know how can I fix this problem. Changing the overhang parameter fixes the overhang problem but it seems that this not a good idea for printing models.
Unfortunately, I can not test the print myself as I do not have a printer myself and I need to outsource the print job.