[bug] boolean: adding body at angle gets double angle

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mago
Posts: 6
Joined: Sat Feb 25, 2017 11:19 am

[bug] boolean: adding body at angle gets double angle

Post by mago »

Hi,
I'm new to this forum as well as to FreeCAD, so may be it's just a problem between chair and keyboard...

Working on my first project i found a strage behavior when i tried to combine (boolean) a base body with several additional bodys that are rotated to different angles. The angles seemd to be randomly altered. I stripped down the issue to a simple setup with 2 bodys, a cube and a cylinder at an angle that i want to combine with the cube.

Steps to reproduce the behavior:
start FreeCAD, create new document
change to Part Design, create new body, sketch, xy plane
draw square, symmetrically extrude to a cube
create a second body sketch xy plane
draw rectangle above / on x axis, rotate around x axis to get a cylinder
with second body active, select placement and rotate 45° around the z axis
now you have a cylinder facing to the edge of the cube
activate first body (cube), click on boolean operation
in the document tree the boolean symbol appears independent, not inside the first body, so i drag the boolean to the first body
doubleclick on boolean, click on "add body", select the cylinder

in preview and after OK the result is a cube with a cylinder in the y-axis
in the document tree the placement of the cylinder body is still at 45°

to get the 45° that i wanted i have to change the placement angle to 22,5°

I tried several different axes and angles and it always looks as if the angle was doubled.

Erratic or at least strange angle behavior with booleans is already discussed here: viewtopic.php?f=19&t=15975
Even though the double angle thing seems to fit there, i have to start a new topic as that's my first post.

OS: "openSUSE Leap 42.2"
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.17.10236 (Git) (Packman)
Build type: Release
Branch: master
Hash: dd20ba3d068c4a0903417d93144f8ac7fed068e9
Python version: 2.7.12
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 6.9.1.oce-0.18-dev

with kind regards,
Martin
chrisb
Veteran
Posts: 53930
Joined: Tue Mar 17, 2015 9:14 am

Re: [bug] boolean: adding body at angle gets double angle

Post by chrisb »

Martin, welcome to the forum and thanks that you searched the forum first and that you tried to minimize the problem so we don't have to track it down in a complicated model. You are right, the link you gave describes exactly the error you have found too. So there is nothing you can do about it at the moment.
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