hello out there
Have a problem with the boolean modifier, while applying a union, lots of non manifolds occur…
at the e place where the "geese"belly overlap it works fine, but where their heads meet, it doesnt…
it looks like the boolean only works like desired at one single place
please have try and hopefully the root of evil will be discovered 
thanks in advance
ps what with where the necks meet?? is this printable???
Could that be a so called “bug” ?
1.Recalculate normals (edit mode: “A” to select all and “ctrl+N” to recalculate)
2.Delete the swan on the left, create a plane, move it and scale it where you want to boolean the center point.
3.Use boolean on the swan and select the plane as the target (i believe i used intersect), apply the booleon.
4.Delete the plane, select the 2 large faces and move the 3d cursor to the center, delete the faces and spawn an empty at the 3d cursor, use the mirror modifier and choose the empty as the target.
Protip: You don’t need that much geometry, create a basic mesh and then use the multires modifier to sculp in finer details. It will look better and should be mostly none-destructive.
boolSwan.blend (2.46 MB)
thanks DC… that helped to make it right…
but still I don t get it why the desired way didn t worked out
Your normals were facing the wrong way, boolean difference should work if you recalculate the normals for both swans.
yes… it should… but doesnt… and after recalculating normals I have exactly same result as before 
For me this is working normally, just calculate the normal and apply boolean modifier.
I downloaded this http://pasteall.org/blend/index.php?id=44178
cool… good for you…
did you tried " show non manifold " with Mesh lint addon??
can you show me screenshot of your result?
what blender version did you use? mine is the 2.78
In version 2.76 or older versions of Boolean works correctly just reverse the normal ones.
In version 2.78 we have the good news of boolean running in two modes (Bmesh and Carve) you are probably using Bmesh, so just change to Carve and the thing should work without “nonmanifolds”.
Using in BMesh mode results in nonmanifolds.
Just reverse the normal ones and apply the Boolean with the activated Carve and check in the MeshLint.
I hope it helped you. Good luck.
thzat worked as desired, thank you sooooooooooooooooooo much…
what a great community here… Blender rules!!!
