3d face object no extrude !

hi;

3d face extrude objects around 4,500 triangles made. While most of them extrude, extrude objects up to 650 yet. I've tried many methods, but this 3D face objects How can I extrude. My goal as a solid curved surface of a mountain and then turn solid model all combine to make straight the following section.

The following are sample files.

above sloping to flat surfaces extending below 3dFace solid objects you want to do.

Greetings.

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