# Advanced Collision Detection - Extensions

**URL:** <https://forums.kodeco.com/t/advanced-collision-detection-extensions/27253>\
**Category:** 3D iOS Games by Tutorials\
**Created:** [March 16, 2017, 3:31am UTC](https://forums.kodeco.com/t/advanced-collision-detection-extensions/27253 "2017-03-16T03:31:01Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![sekorn](https://assets.chunter.kodeco.com/user_avatar/forums.kodeco.com/sekorn/32/67431_2.png) [@sekorn](https://forums.kodeco.com/u/sekorn)\
**Post date:** [March 16, 2017, 3:31am UTC](https://forums.kodeco.com/t/advanced-collision-detection-extensions/27253/1 "2017-03-16T03:31:01Z")

</div>

So I’m up to the part in the book where I’m adding extensions for the SCNSceneRendererDelegate but XCode doesn’t seem to recognize the extension?

The final example from the book will step in to the game loop just fine but for whatever reason, when I add the extension it’s not recognized.

Anyone else encounter this?