Separating shared vanishing points of 3d boxes is broken

[Diederik van Lierop]

Steps to reproduce:

1) Draw a 3D box
2) Draw another 3D box -> both boxes will share the vanishing points
3) Press SHIFT, and drag one of the vanishing boxes

One of the boxes will transform properly, while the other will jump to a wrong transformation

Expected behavior: only one 3D box deforms, the other should stay put.

Inkscape rev. 14253 on Fedora 22

[Diederik van Lierop (mail-diedenrezi)]

Not sure if this is related but this is printed to the command line when creating a 3D box:

** (inkscape:3177): CRITICAL **: virtual void Inkscape::XML::SimpleNode::changeOrder(Inkscape::XML::Node*, Inkscape::XML::Node*): assertion 'child != ref' failed

** (inkscape:3177): CRITICAL **: virtual void Inkscape::XML::SimpleNode::changeOrder(Inkscape::XML::Node*, Inkscape::XML::Node*): assertion 'child != ref' failed

Next, after a second 3D box has been drawn and while SHIFT-dragging the vanishing point:

(inkscape:3177): GLib-GObject-WARNING **: instance of invalid non-instantiatable type '(null)'

(inkscape:3177): GLib-GObject-CRITICAL **: g_signal_handlers_disconnect_matched: assertion 'G_TYPE_CHECK_INSTANCE (instance)' failed

[su_v (suv-lp)]

Based on tests with archived builds (on OS X 10.7.5):
- not reproduced with Inkscape 0.48.5, 0.91 r13725,
- not reproduced with Inkscape 0.91+devel rev <= 13781,
- reproduced with Inkscape 0.91+devel rev >= 13784;
the unexpected transformation of one of the 3dboxes seems related to changes in:
Revision 13784: Store 3d box tool coordinates stored in 'user units'.
http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/13784

[su_v (suv-lp)]

The console messages from 'GLib-GObject' have been noted in earlier reports too:
bug #1235369, bug #1400702, bug #1447494

The ones about Inkscape::XML::SimpleNode::changeOrder() AFAICT only happen with more recent trunk builds:
Based on tests with archived builds:
- not present with 0.91+devel rev <= 14137,
- present with 0.91+devel rev >= 14142;
they are possibly related to the changes in rev 14142 (Fix for bug #1194091):
http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/14142

[su_v (suv-lp)]

Unsurprisingly, the scaling and displacement of the one 3dbox - which is expected to keep the unmodified perspective based on the initial position of the vanishing points - is not triggered when applying the 'steps to reproduce' in new documents based on 'px' templates (e.g. 'default px').