0004589: Edit|Placement generates the wrong Center when object is already translated. - FreeCAD Tracker

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ID	Project	Category	View Status	Date Submitted	Last Update

0004589	FreeCAD	Bug	public	2021-03-08 02:18	2021-03-13 21:21

Reporter	edwilliams16	Assigned To
Priority	normal	Severity	minor	Reproducibility	always
Status	confirmed	Resolution	open
Platform	Mac	OS	OSX	OS Version	10.13.6
Product Version	0.19

Summary	0004589: Edit\|Placement generates the wrong Center when object is already translated.
Description	Discussed in https://forum.freecadweb.org/viewtopic.php?f=3&t=56393
Steps To Reproduce	Create a nominal part box. In the properties, set position_y to 30 mm Open Edit\|Placement Click on "Center of Mass" Choose x-axis Try various angles and note that the body translates as well as rotating about an axis through the CG. Note that the documentation and user expectation would expect only that the axis of rotation would shift from the box origin to through the CG. The problem is that the "Center" should be relative to the box's local origin and should not have the translation added in. In the code, the "position" needs to be subtracted from the CG location so it is relative. The same error occurs when using the "selected points" dialog. The point locations need to have the position vector subtracted from them to create the center. From https://wiki.freecadweb.org/Placement#Using_.22Center.22_to_Control_Axis_of_Rotation "Now consider the case of selecting 2 points. You would select the 2 desired points, and then click the Selected points button. The coordinates of the midpoint between the 2 selected points get placed into the X, Y, and Z spinboxes within the Center section. Now any rotation done on the object will be about this center of rotation." except this isn't what happens if the object is already translated...
Tags	No tags attached.

FreeCAD Information	OS: macOS High Sierra (10.13) Word size of OS: 64-bit Word size of FreeCAD: 64-bit Version: 0.19.24267 (Git) Build type: Release Branch: master Hash: b2ca86d8d72b636011a73394bf9bcdedb3b109b7 Python version: 3.8.8 Qt version: 5.12.5 Coin version: 4.0.0 OCC version: 7.4.0 Locale: C/Default (C)

Date Modified	Username	Field	Change
2021-03-08 02:18	edwilliams16	New Issue
2021-03-13 21:21	Kunda1	Status	new => confirmed