# 4.6 - Real-time preview of vector and scalar parameters doesn't work

**URL:** <https://forums.unrealengine.com/t/4-6-real-time-preview-of-vector-and-scalar-parameters-doesnt-work/300619>\
**Category:** Asset Creation\
**Tags:** UE4-6, unreal-engine, question\
**Created:** [December 4, 2014, 9:54pm UTC](https://forums.unrealengine.com/t/4-6-real-time-preview-of-vector-and-scalar-parameters-doesnt-work/300619 "2014-12-04T21:54:57Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![kylawl](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@kylawl](https://forums.unrealengine.com/u/kylawl)\
**Post date:** [December 4, 2014, 9:54pm UTC](https://forums.unrealengine.com/t/4-6-real-time-preview-of-vector-and-scalar-parameters-doesnt-work/300619/1 "2014-12-04T21:54:57Z")

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The new real-time preview for scalar and vector parameters isn’t real-time.

For me it is still recompiling the shader after every parameter change (exactly the same as the behaviour for a vector/scalar constant).

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**Author:** ![Lovecraft\_K](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Lovecraft\_K](https://forums.unrealengine.com/u/Lovecraft_K)\
**Post date:** [December 5, 2014, 3:08pm UTC](https://forums.unrealengine.com/t/4-6-real-time-preview-of-vector-and-scalar-parameters-doesnt-work/300619/2 "2014-12-05T15:08:23Z")

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Hey kylawl -

The real time preview should be working in the level viewports on a mesh with the material applied. The Material Preview viewport will still behave as before and compile through the default material. This is expected and intended behavior.

Thank You

Eric Ketchum

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**Author:** ![kylawl](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@kylawl](https://forums.unrealengine.com/u/kylawl)\
**Post date:** [December 5, 2014, 6:10pm UTC](https://forums.unrealengine.com/t/4-6-real-time-preview-of-vector-and-scalar-parameters-doesnt-work/300619/3 "2014-12-05T18:10:39Z")

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Hi Eric, so I see that it updates the scene objects, but should I have to click ok on the colour picker? I would expect it to either update while I’m dragging or at least when I drag and release?

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**Author:** ![Lovecraft\_K](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Lovecraft\_K](https://forums.unrealengine.com/u/Lovecraft_K)\
**Post date:** [December 5, 2014, 7:54pm UTC](https://forums.unrealengine.com/t/4-6-real-time-preview-of-vector-and-scalar-parameters-doesnt-work/300619/4 "2014-12-05T19:54:31Z")

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Hey kylawl -

Thank you for the clarification. This behavior does appear to be a bug. I’ve reported it to our engineers to look into, for reference UE-6341.

I will keep you informed as we continue to investigate this issue.

Eric Ketchum

EDIT: kylawl - You should be able to bring in a Vector Parameter (Hold V down and Click) directly and it will function correctly. We are looking into why the converted Vector 3 or 4 to a parameter is not functioning as intended.