I have to do a mold and I have several flat faces, and I need to reduce the face counts, also because I will use the obj file in other programs. I got to this point after working in the flat faces: Select area> X (remove faces) > select contour > Fill > Select Face (1) (first picture)
When I select Face (big) and Subdivide it makes a subdivision of a face in several small corners, not big divisions.
I think I'm doing something wrong because when I Export as .OBJ to another software, these big faces are not recognized (a hole appears in the object), (for example meshmixer). Do you know why? How it could be solved?
To decide the Subdivision point I think I could solve the problem selecting 2 vertex and Fill, but I still have the problem of "ghost faces".