Blender Foundation: Blender 2.x BF release: Detail: 32866 Crash by cyclic use of Boolean Modifier

Log In
New Account

[#32866] Crash by cyclic use of Boolean Modifier

Date:
2012-10-13 04:50 Priority:
3

State:
Closed

Submitted by:
Shinsuke Irie (irie) Assigned to:
Campbell Barton (campbellbarton)

Category:
Modifiers Status:
Fixed / Closed

Relates to: Duplicates:

Patches:

Summary:
Crash by cyclic use of Boolean Modifier

Detailed description

Steps to reproduce:

1. Create 2 cubes (cube1, cube2)
2. Add boolean modifier to cube1 and set Object=cube2
3. Add boolean modifier to cube2 and set Object=cube1

Then Blender crashes immediately outputting the following message:

Dependency cycle detected:
cube1 depends on cube2 through Boolean Modifier.
cube2 depends on cube1 through Boolean Modifier.

Segmentation fault (core dumped)
$

Such use of the modifier makes no sense, but we might do that accidentally and lose our data unexpectedly.

r51289
Ubuntu 12.10 amd64

Followup

Message

Date: 2012-10-13 11:19
Sender: Bastien Montagne
We just run into an infinite loop, as boolean modifier expects the final mesh (i.e. with all modifiers applied) of its second operand…

Not sure though how to nicely fix that, perhaps returning to 2.63 code in applyModifer when getting second operand's dm (it indeed fixes the crash)? Or placing a sort of "watchdog" to prevent recursion?

Will leave this one to sergey! :)

Date: 2012-10-15 14:04
Sender: Sergey Sharybin
That was a change from Campbell to support some special cases when objects from different layers are used.

Campbell, this indeed should be solved in a different way. Could you look into this?

Side note: the same could happen with array modifier when recursion appears on Start/End cap objects.

Date: 2012-11-10 04:24
Sender: Brecht Van Lommel
At some point I changed all modifiers to use only derivedFinal and just fail if it is not available. This reveals issues in our dependency graph of course, which may not be possible to fix without a major refactor.

If this is an important case to have working now, it could do some manual check for recursion, like a flag in the modifier that is set/cleared before/after running.

Date: 2012-11-10 14:24
Sender: Moolah Nasreddin
IMO, Blender lacks of "solid" working modifiers for creating full range of modern particle and mesh FX. So by now I suppose it's really better to have some hacks (before that major refactor) for several modifiers than NOT to have them. Boolean is a very important modifier for creating complex effects without tricky workarounds.

Date: 2013-01-23 06:45
Sender: Campbell Barton
Committed workaround r54017, but ideal but avoids crash.

Attached Files:

No Files Currently Attached

Changes:

Field	Old Value	Date	By

Status	Confirmed	2013-01-23 06:45	campbellbarton
close_date	None	2013-01-23 06:45	campbellbarton
status_id	Open	2013-01-23 06:45	campbellbarton
assigned_to	nazgul	2012-10-15 14:04	nazgul
assigned_to	none	2012-10-13 11:19	mont29
Status	New	2012-10-13 11:19	mont29