snap to face broken with mirror modifier #68674

New Issue

Casey Connor · 2019-08-15T05:13:06+02:00

Casey Connor commented

2019-08-15 05:13:06 +02:00

System Information
Operating system: Linux-4.18.0-25-generic-x86_64-with-debian-buster-sid 64 Bits
(same behavior on Windows 8.1)

Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 390.116

Blender Version
Broken: version: 2.81 (sub 11), branch: master, commit date: 2019-09-12 22:20, hash: 8d12c2a836
Also broken in 2.80 stable

open demonstration blend file with no config dir
note that snap-to-face (target:closest, affect:move) is already enabled
select small cuboidal in lower left
G, then X, to move along X, and attempt to snap to broad side of nearby horizontal cuboidal
see that the object flashes erratically, alternately assuming its original position, and alternately assuming an incorrectly snapped position
if instead the cuboidal we are trying to move is moved a bit first, without snapping, and then we again try to snap to the face, it doesn't flicker any more, but it still snaps incorrectly (and actually still does flicker on the overlapping face but doesn't jump around in position)
if the mirror modifier on the cuboidal we are trying to move is disabled, it snaps correctly

Starting position:

Incorrect snap result:

Correctly snapped result:

Demo blend file: snapbug.blend

**System Information** Operating system: Linux-4.18.0-25-generic-x86_64-with-debian-buster-sid 64 Bits (same behavior on Windows 8.1) Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 390.116 **Blender Version** Broken: version: 2.81 (sub 11), branch: master, commit date: 2019-09-12 22:20, hash: `8d12c2a836` Also broken in 2.80 stable * open demonstration blend file with no config dir * note that snap-to-face (target:closest, affect:move) is already enabled * select small cuboidal in lower left * G, then X, to move along X, and attempt to snap to broad side of nearby horizontal cuboidal * see that the object flashes erratically, alternately assuming its original position, and alternately assuming an incorrectly snapped position * if instead the cuboidal we are trying to move is moved a bit first, without snapping, and then we again try to snap to the face, it doesn't flicker any more, but it still snaps incorrectly (and actually still does flicker on the overlapping face but doesn't jump around in position) * if the mirror modifier on the cuboidal we are trying to move is disabled, it snaps correctly Starting position: ![starting_position.png](https://archive.blender.org/developer/F7665332/starting_position.png) Incorrect snap result: ![result.png](https://archive.blender.org/developer/F7665338/result.png) Correctly snapped result: ![desired_result.png](https://archive.blender.org/developer/F7665344/desired_result.png) Demo blend file: [snapbug.blend](https://archive.blender.org/developer/F7665323/snapbug.blend)

Casey Connor commented

2019-08-15 05:13:06 +02:00

Added subscriber: @clepsydrae

Casey Connor commented

2019-08-19 22:57:38 +02:00

Same behavior on Windows 8.1, for the record.

Casey Connor commented

2019-09-13 07:26:10 +02:00

Tested in latest 2.81 as well: still broken

Germano Cavalcante commented

2019-09-13 15:26:09 +02:00

Added subscribers: @ideasman42, @mano-wii

Germano Cavalcante self-assigned this 2019-09-13 15:26:09 +02:00

Germano Cavalcante commented

2019-09-13 15:26:09 +02:00

The problem is that the Snap with of type Closest uses the bound box to snap.
But in this case the bound box varies with the movement.
One solution would be to use Texture Space as it does not change.
@ideasman42, any ideas?

The problem is that the `Snap with` of type `Closest` uses the bound box to snap. But in this case the bound box varies with the movement. One solution would be to use Texture Space as it does not change. @ideasman42, any ideas?

Germano Cavalcante was unassigned by Dalai Felinto

2019-12-23 16:33:18 +01:00

Germano Cavalcante commented

2020-01-24 23:10:32 +01:00

Marked as Known Issue because it is necessary to plan carefully on what to do in these cases and because the problem can be easily remedied by the user.

Marked as `Known Issue` because it is necessary to plan carefully on what to do in these cases and because the problem can be easily remedied by the user.

Philipp Oeser removed the

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snap to face broken with mirror modifier #68674