Problem with boolean cut operation

[WalkingShadow]

screenshot_2.png (308.32 KiB) Viewed 2343 times

OS: Ubuntu 14.04.2 LTS
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.15.4671 (Git)
Branch: (détaché de origin/releases/FreeCAD-0-15)
Hash: 244b3aef360841646cbfe80a1b225c8b39c8380c
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17

I have three solids and wish to make a union of two of them, then cut with the third. FreeCAD complains that the loft is not a solid.

In the attached file, I can cut the ellipsoid with the ellipse_extrude, and I can cut the loft with the ellipse_extrude, but if I make a union of the ellipsoid and the loft, I cannot cut the fusion with the ellipse_extrude.

Am I doing something wrong?

[shoogen]

The "Fusion" contains the Solid and an additional Vertex at (7.65404249467096e-16, -1.94968771746042e-31, 15.0).

[WalkingShadow]

Do you mean I have somehow inadvertently created a superfluous vertex? I recreated my model from scratch and still have the same error.

[NormandC]

The "Fusion" contains the Solid and an additional Vertex at (7.65404249467096e-16, -1.94968771746042e-31, 15.0).

The X and Y coordinates are very near zero. The top of Ellipsoid and Ellipse001 have the same Z coordinate (15.0). I'd wager the superfluous vertex is exactly at the tangency point of the top face of bezel-Loft and Ellipsoid. Tangency conditions like that are not recommended for booleans because the geometric modeling kernel struggles with them.

If you were to raise the Z coordinate of Ellipse001 by even a tiny value (like 15.0001), I'll bet this superfluous vertex will disappear. I can't confirm this though, as I'm pretty sure shoogen found out from the python console (which I don't personally use). With the change in Z height, even though I got the same error as in your screen capture, I clicked OK anyway and the Part Cut seemed to succeed between Fusion and ellipse_extrude.

boolean_cut_WalkingShadow_01.png (31.29 KiB) Viewed 2287 times

[shoogen]

I can't confirm this though, as I'm pretty sure shoogen found out from the python console (which I don't personally use).

Yes, this should be recognized by the ShapeCheck command. http://tracker.dev.opencascade.org/view.php?id=26078

[WalkingShadow]

I increased the height of the loft by 1mm, and the cut worked as expected. Thanks for the help.