As I can not get into the Turbo Cad Forum I am just hoping someone here may be able to help me.

I have drawn a rectangle, then extruded it to 10mm, I then deleted the 2d rectangle.

I then drew various circles on the surface of the rectanglular block (using the same plane), then extruded them 10 mm through the rectangular block. Again deleting the 2d circles after.

When I tried to 3D subtract the holes from the rectanglular block, I managed one of them, but the rest report 'The resultant TC Surface is degenerated. The boolean operation is discarded' !

I often get this and have no idea what is wrong, somehow I usually get there in the end by deleting and redrawing them but what is the problem ???

Any help would be appreciated. I am using Turbo CAD V8

Nick