Hi ...

Please see the enclosed topographical model (a small part of a model with changes in topo and buildings added.

The problem is that over considerable time and model variations I have created some small (and large) holes in the surface.

I would like to close the smaller ones but am finding that I cannot do it (I can't find a 'rebuild' type command) ... so I tried to create a solid plug for the larger of the small holes. No problem with that but ...

I thought I could use boolean difference to trim the protruding solid so that I would have a uniform plug at the larger surface ... but this process does not seem to work. Probably there is something wrong with the larger surface that I cannot see.

So here it is ... I am sure someone can tell me where I am going astray.

thanks,
eric