Hello 

i'm working with a few stl files and i have few questions regarding the import diag tool:

1) from experience i know that there are few errors that can appear in the import diag

message .

is there a chance , sombody here will explain to me what are the critical erros that requires running import diag at any costs and if there are any errors that  can be fix when sending the part to 3 printing.

2) since i couldn't use the attempt to heal all bottom on all the parts, i tried to fix  some faces individually.

in some cases instead of reducing the number of faces i got a larger number of faces .

can sombody hear explain to me why.?