# Nav modifier component broken in blueprints

**URL:** <https://forums.unrealengine.com/t/nav-modifier-component-broken-in-blueprints/322543>\
**Category:** Blueprint\
**Tags:** bug, nav-mesh-bounds-volu, nav-mesh, unreal-engine, bug-report, question, Blueprint\
**Created:** [June 21, 2015, 4:52pm UTC](https://forums.unrealengine.com/t/nav-modifier-component-broken-in-blueprints/322543 "2015-06-21T16:52:10Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![Tekoppar](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Tekoppar](https://forums.unrealengine.com/u/Tekoppar)\
**Post date:** [June 21, 2015, 4:52pm UTC](https://forums.unrealengine.com/t/nav-modifier-component-broken-in-blueprints/322543/1 "2015-06-21T16:52:10Z")

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The nav modifier component in blueprint is broken, in 4.7.6 they worked like the normal nav modifier volumes. At the moment the nav modifier component will only work if “Can Ever Affect Navigation” is checked to true and if the “Pawn” or “Vehicle” collision response is set to block in the root component of the blueprint. If you try changing these settings in a child the editor will either crash or you won’t be able to compile the blueprint anymore, changing the settings back doesn’t matter, you will still get the error.

If you don’t have those set you will get this error in the output log, LogNavOctree:Warning: Can’t add node [NavModifier] - parent [Box] not found in octree!

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**Author:** ![anonymous\_user\_b9532c9a](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_b9532c9a](https://forums.unrealengine.com/u/anonymous_user_b9532c9a)\
**Post date:** [June 21, 2015, 7:31pm UTC](https://forums.unrealengine.com/t/nav-modifier-component-broken-in-blueprints/322543/2 "2015-06-21T19:31:14Z")

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Hi ,

Have you tried this in a clean project with no additional content or is this limited to one project? What specific steps are you taking that reproduce this on your end?

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**Author:** ![Tekoppar](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Tekoppar](https://forums.unrealengine.com/u/Tekoppar)\
**Post date:** [June 21, 2015, 8:13pm UTC](https://forums.unrealengine.com/t/nav-modifier-component-broken-in-blueprints/322543/3 "2015-06-21T20:13:45Z")

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Happens on new projects too.

New blueprint class \> actor \> add box collision \> add nav modifier = Nav mesh won’t change until you change the collision settings of the components.

For the crash it seems to be caused by changing the collison settings, toggling the “Can Ever Affect Navigation” on/off and moving a component. I also get the semi permanent holes in the navigation bug when I do this, where if I set the collision so the navigation mesh rebuilds and toggle the “Can Ever Affect Navigation” to off and move the blueprint. The hole that was built by the moved mesh will be kept there until I restart the project.

link text

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**Author:** ![anonymous\_user\_b9532c9a](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_b9532c9a](https://forums.unrealengine.com/u/anonymous_user_b9532c9a)\
**Post date:** [June 21, 2015, 9:25pm UTC](https://forums.unrealengine.com/t/nav-modifier-component-broken-in-blueprints/322543/4 "2015-06-21T21:25:17Z")

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Hi ,

I haven’t been able to reproduce the crash, however I was able to reproduce the navmodifier error in which the navmesh will not change. I’ve entered a bug report, UE-17437 to be assessed by the development staff. Do you have any steps I can take to reproduce the crash? Additionally can you upload the crash logs? The link you provided is the callstack. To get the logs, go to \Unreal Projects\PROJECTNAME\saved\logs. Thank you!

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**Author:** ![Tekoppar](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Tekoppar](https://forums.unrealengine.com/u/Tekoppar)\
**Post date:** [June 21, 2015, 10:10pm UTC](https://forums.unrealengine.com/t/nav-modifier-component-broken-in-blueprints/322543/5 "2015-06-21T22:10:33Z")

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I’ve found a consistent setup with a project. Heres a video I recorded of the setup; [https://dl.dropboxusercontent.com/u/9876544/Desktop%202015.06.22%20-%2000.04.36.02.mp4](https://dl.dropboxusercontent.com/u/9876544/Desktop%202015.06.22%20-%2000.04.36.02.mp4) and the project I used; [https://dl.dropboxusercontent.com/u/9876544/MyProject.rar](https://dl.dropboxusercontent.com/u/9876544/MyProject.rar)

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**Author:** ![anonymous\_user\_b9532c9a](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@anonymous\_user\_b9532c9a](https://forums.unrealengine.com/u/anonymous_user_b9532c9a)\
**Post date:** [June 22, 2015, 7:39pm UTC](https://forums.unrealengine.com/t/nav-modifier-component-broken-in-blueprints/322543/6 "2015-06-22T19:39:37Z")

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Hi ,

I was able to reproduce this and have entered a bug report, UE-17468, to be assessed by the development staff.