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Grease Pencil editing while parented is not rotating correctly
Open, Confirmed, MediumPublic


System Information
Operating system: Windows-10-10.0.17134 64 Bits
Graphics card: Intel(R) UHD Graphics 620 Intel 4.5.0 - Build

Blender Version
Broken: version: 2.80 (sub 57), branch: master, commit date: 2019-04-14 19:18, hash: rB860a9f979d60
Worked: (optional)

Short description of error
I can't get rotation of the vertices in edit mode to work as expected when the GP is parented to an empty and that empty moves (is keyframmed)

Exact steps for others to reproduce the error
Start a GP layer. draw a diamond shape.
create an empty.. and parent the GP layer to it.

keyframe the empty to move from frame 1 to frame 10.

now edit the GP. select some vertices.. go to frame 5. here is where the rotation just doesn't work...
if i use Cursor pivot and place the cusor right at one of the vertices, you can see that it does not rotate at that point.
if i choose the origin or selected vertices or any of the other rotation modes- it does not work (maybe its taking the origin of the GP Object which we would never want in edit mode)

I hope you fix this before your July release.. excited.



Event Timeline

Sebastian Parborg (zeddb) triaged this task as Needs Information from User priority.Apr 16 2019, 12:44 PM

Could you attach a sample .blend file?

here is a file although not in the latest version. (I guess it has been a problem forever)
I figured out the problem...

lets concentrate on rotate around a Cursor in GP edit mode.

When you enter this file everything will work.. it will rotate on the cursor as pivot..

but while in this edit mode... move(scrub) your frame to ...6 for example.

Now move your cursor pivot point and it WON'T rotate correctly.. BUT I just figured out IF you exit edit mode, then immediately go back into edit mode, THEN it will rotate again on the cursor. So it has to "reCalulate" apparently.

Again, this happens when GP is parented to an empty (an object) and you have keyframes on that object.

If Antonio can fix it to "recalculate" while scrubbing frames WHILE remaining in GP edit mode.. then it will be fixed.

Thank you

Sebastian Parborg (zeddb) raised the priority of this task from Needs Information from User to Confirmed, Medium.Apr 17 2019, 11:44 AM

@j p (caricaturize) Did you test to parent the grease pencil object to empty, instead to parent the GP layer?

No i did not test GP object to empty (I am very experienced with 2.79 and I always parented layer to empty.)

My workflow requires to rotate only selected vertices so i can rotate an arm for example.

Bottom line is that layer to empty parenting works...but in edit mode it is not refreshing the pivot point if we scrub the timeline.

(if the empty has keyframes- the interpolation doesn't refresh with the   GP rotation pivot point in edit mode    unless we quickly  get out of edit mode(to go object mode) and immediately go back into edit mode.)


draw a few lines in GP so you will be able to tell if it is rotated
parent that GP layer to empty
keyframe that empty on layer 0
scrub timeline to frame 10
move the empty across the screen and keyframe it on frame 10
Scrub timeline back to frame 0
select gp object
select all vertices
set CURSOR mode as pivot point.
rotate the selection, it works
scrub the timeline to frame 5
click in view to set the Cursor for the pivot point.
rotate the selection and it will NOT rotate around this cursor.

go to object mode
go back into edit mode

rotate the selection and it WILL rotate correctly