QUOTE(Hasepuh @ 03/29/09, 09:43 PM) [snapback]304291[/snapback]
Is there any trick that might help to complete the operation successfully?
Yes.
But it wont help you 99% of the time. Thing is it dissapears because your supplying it with a value that doesnt make sense. Booleans work on real world geometry*. Most of the time maya users dont really venture into the realm of real world geometry, so you must check that all your normals are consistent, you have no gaps, your objects is atleast localy closed and makes sense. Avoid any cases where a face would become coplanar and for ovious reasosn non manifold geometry will not work. It takes just one face or point to be wrong and its no deal. Ok, now booleans always work if you supply it with something that CAN Boolean in first place.
Try apoly cleanup, point merge and normals conform (and meak sure all subshells conform to a sane direction), and sligt nudge. This attacks 50% of inexperienced users mistakes. This si the good news. for another 10% delete one of the first faces and recrate it for new locality that booleans easier, this works for imported polys that are in jumble that cabt be booleaned.
Now for the bad news. All this said you don't want to do booleans on polygons. This is totaly outside the fact that your not succeeding it the boolean in the firts place. Theres a EVEN bigger reason not to use them than why your boolean doesnt work at play here.
See polygons don't represent anything tangible. On the other hand they have a very strictly defined surface, and on the other they represent a approximation of something that depends on your tangents. Theese 2 things conflict with each other. A boolean can only work with the strict definition of the surface. But thsts not what you precieve being there so a boolean with polygons usually results in something you dindt anticipate. NOt so much because the boolean wouldnt be preice. But because its WAY too precice and your being very wague. The result is that if you try to boolean ANYTHING even remotely curved you end up with a surface thet wont work out for you.
Imagine:
first image is what you have got black is what you think you have and red is what you actually do.
middle picture black is what you really get after boolean wheras red shows what you think you get.
Last picture blue is what you think you Ought to get and red si what you got.**
*tough it appears many modellers dont know when geometry is real. Maya has no cheks in place that forces you to do real geometry.
** no its not possble to solve ehat you think you should get as the solutions may be virtual and the surface can be precieved as many different solutions.