# Geometry Collections and Distance-Fields / Ray Tracing

**URL:** <https://forums.unrealengine.com/t/geometry-collections-and-distance-fields-ray-tracing/869546>\
**Category:** Rendering\
**Tags:** Geometry-Cache, distance-fields, unreal-engine, Destructible-Mesh, fracture, Path-Tracing\
**Created:** [April 7, 2023, 6:53am UTC](https://forums.unrealengine.com/t/geometry-collections-and-distance-fields-ray-tracing/869546 "2023-04-07T06:53:42Z")\
**Posts on this page:** 1\
**Showing post:** 4

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**Author:** ![Arkiras](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/arkiras/32/1008648_2.png) [@Arkiras](https://forums.unrealengine.com/u/Arkiras)\
**Post date:** [April 7, 2023, 4:29pm UTC](https://forums.unrealengine.com/t/geometry-collections-and-distance-fields-ray-tracing/869546/4 "2023-04-07T16:29:34Z")

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Just keep in mind, they’re hidden from the raytracing view by default because the raytracing accelleration structure needs to be rebuilt every frame for them which is extremely expensive. Probably fine for cinematics though.

Regarding mesh distance fields, I asked about this in early access and this is the response i got:

> [@Lumen GI and Reflections feedback thread](https://forums.unrealengine.com/t/lumen-gi-and-reflections-feedback-thread/501108/10):
>
> > I would really like to know if there are any plans to improve support for chaos geometry collections, currently they don’t appear to generate distance fields and as a result have no representation in the Lumen scene.
> 
> We’d like to implement distance fields for Geometry Collections but it would be pretty far down the priority list. Hardware Ray Tracing already supports Geometry Collections, however as a dynamically deforming mesh, it will cause an acceleration structure rebuild every frame so you’ll have to watch out for the performance cost.

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