# Rendering anomaly with CorridorGeometry and GroundPrimitive

**URL:** <https://community.cesium.com/t/rendering-anomaly-with-corridorgeometry-and-groundprimitive/3062>\
**Category:** CesiumJS\
**Created:** [September 15, 2015, 12:53pm UTC](https://community.cesium.com/t/rendering-anomaly-with-corridorgeometry-and-groundprimitive/3062 "2015-09-15T12:53:42Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![andrewca000](https://avatars.discourse-cdn.com/v4/letter/a/7bcc69/32.png) [@andrewca000](https://community.cesium.com/u/andrewca000)\
**Post date:** [September 15, 2015, 12:53pm UTC](https://community.cesium.com/t/rendering-anomaly-with-corridorgeometry-and-groundprimitive/3062/1 "2015-09-15T12:53:42Z")

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Any ideas why the following sandcastle renders the red GroundPrimitive in this way? I like the ability to draw the corridor on the ground, but I get this behavior a lot with my primitives - instead of smooth, rounded ends, there are strange patterns and sharp edges. If I remove the first point it looks ok again - are the points too tightly spaced? Is this something you’ve seen before? I appreciate your help, as always.

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**Author:** ![Matt\_Amato](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/matt_amato/32/1993_2.png) [@Matt\_Amato](https://community.cesium.com/u/Matt_Amato)\
**Post date:** [September 16, 2015, 2:22am UTC](https://community.cesium.com/t/rendering-anomaly-with-corridorgeometry-and-groundprimitive/3062/2 "2015-09-16T02:22:51Z")

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This definitely looks like a bug, I submitted the following issue to Github so we remember to take a look at it: [https://github.com/AnalyticalGraphicsInc/cesium/issues/3035](https://github.com/AnalyticalGraphicsInc/cesium/issues/3035)