hi 
i created an object with BooleanDifference and one of the face on the surface object did not shaded, like a hole.
how can i solve this problem? 
thanks
pic of the problem
it looks like you created a messy surface consisting of several joined surfaces. anyway if the operation went correct and its just displaying it odd you can try to explode and rejoin, but if the operation itself created a missing surface then you can still explode it then use untrim on the broken surface and retrim it with the surface of that letter perimeter if the broken surface was part of one consistent surface. but looking at how fragmented this perimeter is i am not sure if thats a good idea you have to try if it works because it also looks like that one trim would run exactly along an isocurve… if thats one at all.
otherwise you have to post the file that people can have a look.
i solved the problem 
i extracted the surface and then fit it with “fitsrf”,
it created a surface and a edges border, i joined the borders and then trimed the border with the face surface and them i “move” the surface in place.
thanks
Hi Al - next time, see if it works to just extract the face, UntrimBorder, then retrim with the surrounding edges, without the refitting step - often a retrim does it on a goofy surface,
-Pascal
thanks pascal: