# Particle update func pgs from doc broken

**URL:** <https://forum.babylonjs.com/t/particle-update-func-pgs-from-doc-broken/62658>\
**Category:** Questions\
**Created:** [March 4, 2026, 7:50am UTC](https://forum.babylonjs.com/t/particle-update-func-pgs-from-doc-broken/62658 "2026-03-04T07:50:15Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![phaselock](https://avatars.discourse-cdn.com/v4/letter/p/da6949/32.png) [@phaselock](https://forum.babylonjs.com/u/phaselock)\
**Post date:** [March 4, 2026, 7:50am UTC](https://forum.babylonjs.com/t/particle-update-func-pgs-from-doc-broken/62658/1 "2026-03-04T07:50:15Z")

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From the docs: [Babylon.js docs](https://doc.babylonjs.com/features/featuresDeepDive/particles/particle_system/customizingParticles/#custom-functions)  
Broken pgs: [https://playground.babylonjs.com/#MRRGXL#950](https://playground.babylonjs.com/#MRRGXL#950), [https://playground.babylonjs.com/#WJBZQH#104](https://playground.babylonjs.com/#WJBZQH#104)

Console is complaining about `_scaledDirection` being undefined or some such. I think this is from some recent work as my local `v8.49.6` is still working fine.

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<div class="post-metadata">

**Author:** ![Evgeni\_Popov](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/evgeni_popov/32/4432_2.png) [@Evgeni\_Popov](https://forum.babylonjs.com/u/Evgeni_Popov)\
**Post date:** [March 4, 2026, 8:41am UTC](https://forum.babylonjs.com/t/particle-update-func-pgs-from-doc-broken/62658/2 "2026-03-04T08:41:47Z")

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Thanks for reporting, this PR will fix the PGs:

> <https://github.com/BabylonJS/Documentation/pull/1532>
>
> Fix after https://github.com/BabylonJS/Babylon.js/pull/17904