Start Impress. Insert a custom shape, e.g. a rectangle from "Basic shapes" floater. Toggle it to extrusion mode. Do not touch the Directions floater in the toolbar. Save the document. Examine the file. It should have an attribute draw:extrusion-skew="50 -135". The default value for this attribute is "50 45", so "50 -135" may not be omitted. But the attribute is missing. Open the file in PowerPoint. It correctly shows the extrusion with skew angle 45 because of the missing attribute. The error was introduced in OOo, although already standard ODF 1.1 has "50 45" as default value.
I gave a first try with https://gerrit.libreoffice.org/c/core/+/113257 (perhaps too naive?)
(In reply to Julien Nabet from comment #1) > I gave a first try with https://gerrit.libreoffice.org/c/core/+/113257 > (perhaps too naive?) That could be at least a solution for LO7.1, because changing the internal handling from default -135 to 45 will surely not happen in 7.1. The comment should state, that LO 7.1 (wrongly) treats internally the value -135 as default value, but that it is not default value in ODF and therefore has to written out. If we take this too for LO 7.2, a warning is needed, that this has to be removed in case the internal handling of default value will be changed from -135 to 45. I think a decision is needed, whether the internal default should be changed at all. A similar problem with writing out the correct value will occur, when we start to export custom shape extrusion to OOXML. [Currently I'm working on the import from OOXML.]
(In reply to Regina Henschel from comment #2) > ... > > I think a decision is needed, whether the internal default should be changed > at all. A similar problem with writing out the correct value will occur, > when we start to export custom shape extrusion to OOXML. [Currently I'm > working on the import from OOXML.] Thank you for your detailed feedback, I thought it would have been simpler, I'm not sure to understand so prefer letting this to experts ; I was indeed a bit too naive! :-) I gave up the patch. => uncc myself.
Moving to NEW
@Julian: Please reopen https://gerrit.libreoffice.org/c/core/+/113257. I have thought about it some time now and think, we should go that way and do not change the internal default value.
Julien Nabet committed a patch related to this issue. It has been pushed to "master": https://git.libreoffice.org/core/commit/773465fb95c1be48f8fdf406d2d39caa142050db tdf#141301: extrusion-skew angle value -135 is not written to file... It will be available in 7.3.0. The patch should be included in the daily builds available at https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: https://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.
Julien Nabet committed a patch related to this issue. It has been pushed to "libreoffice-7-2": https://git.libreoffice.org/core/commit/0ec2f94100cf1b8c24642e79e60810a79ff075c3 tdf#141301: extrusion-skew angle value -135 is not written to file... It will be available in 7.2.3. The patch should be included in the daily builds available at https://dev-builds.libreoffice.org/daily/ in the next 24-48 hours. More information about daily builds can be found at: https://wiki.documentfoundation.org/Testing_Daily_Builds Affected users are encouraged to test the fix and report feedback.