# Problem with shadows in the cutting plane

**URL:** <https://discourse.slicer.org/t/problem-with-shadows-in-the-cutting-plane/15551>\
**Category:** Support\
**Created:** [January 16, 2021, 6:41am UTC](https://discourse.slicer.org/t/problem-with-shadows-in-the-cutting-plane/15551 "2021-01-16T06:41:52Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Andreas](https://avatars.discourse-cdn.com/v4/letter/a/ee7513/32.png) [@Andreas](https://discourse.slicer.org/u/Andreas)\
**Post date:** [January 16, 2021, 6:41am UTC](https://discourse.slicer.org/t/problem-with-shadows-in-the-cutting-plane/15551/1 "2021-01-16T06:41:52Z")

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Hello everyone,

I have a problem with the representation of the cutting plane in a vessel section, it becomes very dark (shown in shadow)

![Bild2](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/9/1/91b809f9194a6eb50d4834ee7aa2eae6095344a1.jpeg)

The cutting plane at the openings of the vessel are shown very clearly

![Bild1](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/e/a/ea4a27b12e8b8def8fb3fd5997fe9787d44fe17c.jpeg)

I already tried to remove it with the Surface Toolbar box (Normals; Splitting), but without success.

Many thanks for your help

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [January 16, 2021, 6:59am UTC](https://discourse.slicer.org/t/problem-with-shadows-in-the-cutting-plane/15551/2 "2021-01-16T06:59:54Z")

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To preserve sharp edges, you need to enable splitting when computing normals (auto-orientation may be useful, too).

You can change the material properties in Models module (make reflection less dependent on direction) or change lighting using Lighting editor module (in Sandbox extension).