# Positions are Required Error from Merge Mesh Optimization SceneOptimizer

**URL:** <https://forum.babylonjs.com/t/positions-are-required-error-from-merge-mesh-optimization-sceneoptimizer/39423>\
**Category:** Bugs\
**Created:** [March 28, 2023, 9:55pm UTC](https://forum.babylonjs.com/t/positions-are-required-error-from-merge-mesh-optimization-sceneoptimizer/39423 "2023-03-28T21:55:40Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![xiehangyun](https://sea2.discourse-cdn.com/flex024/user_avatar/forum.babylonjs.com/xiehangyun/32/30777_2.png) [@xiehangyun](https://forum.babylonjs.com/u/xiehangyun)\
**Post date:** [March 29, 2023, 1:39am UTC](https://forum.babylonjs.com/t/positions-are-required-error-from-merge-mesh-optimization-sceneoptimizer/39423/2 "2023-03-29T01:39:27Z")

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Mesh merging requires that all grids have the same kinds of geometry, must contain the kind: position, and must have the same sideOrientation. If you’re thinking about optimizing scene rendering performance, check out this article： [Scene rendering performance optimization plugin based on instance object - Demos and projects - Babylon.js (babylonjs.com)](https://forum.babylonjs.com/t/scene-rendering-performance-optimization-plugin-based-on-instance-object/39083)

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