after boolean snap don't work
Closed, ArchivedPublic

Description

System Information
win7 64bit gtx1070

Blender Version
Broken: 2.78c

Short description of error
after the boolean operation, with the modifier still active, the boolean object is not affected by the snap anymore.

Exact steps for others to reproduce the error
move the selected object and you will see that the snaps don't work anymore.
thankyou

Details

Type
Bug

This would be understandable as the surface of the object is affected by the boolean object. However it should at least work when the modifier is hidden, which is not the case. We have to remove the object from the modifier or remove the modifier itself.

Sergey Sharybin (sergey) closed this task as Archived.Sep 15 2017, 9:40 AM
Sergey Sharybin (sergey) claimed this task.

Thanks for the report, but it' not really a bug.

What's happening here is that transform system will not allow to snap object which is dependent on currently editing one. This is needed to avoid feedback loops which will ruing your scene. This is done based on dependency graph relations. Those relations are based on modifier stack and not based on modifier visibility flags. Making relations aware of modifier visibility will cause depsgraph rebuilds on every modifier visibility toggle, which isn't really something you want from performance point of view. But additionally, making relations aware of such visibility will make it really hard to spot dependency cycles when some modifier is only enabled for render and not for viewport.

So while this is annoying issue, we can't really make snapping to work here as you expect: if modifier is enabled, then you hit feedback cycle and object will snap to some weird location., disabled modifiers are tricky to support and still somewhat unpredictable and useless for snapping.