# Urgent suggestions needed. Small vrayLightmat objects flickering.

**URL:** <https://forums.chaos.com/t/urgent-suggestions-needed-small-vraylightmat-objects-flickering/18472>\
**Category:** Issues\
**Created:** [June 19, 2008, 1:32pm UTC](https://forums.chaos.com/t/urgent-suggestions-needed-small-vraylightmat-objects-flickering/18472 "2008-06-19T13:32:01Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![re\_FORM](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/re_form/32/36295_2.png) [@re\_FORM](https://forums.chaos.com/u/re_FORM)\
**Post date:** [June 19, 2008, 1:32pm UTC](https://forums.chaos.com/t/urgent-suggestions-needed-small-vraylightmat-objects-flickering/18472/1 "2008-06-19T13:32:01Z")

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I’ve got a scene with loads of blocks of varying sizes with vraylightmats applied. The smaller objects flicker randomly for some reason.

I’m using “sub-pixel mapping”, Adaptive-dmc 1/24, Noise Thresh of .005  
No GI.

There are NO coplanar surfaces 🙂 although it does look like its a coplaner surfaces problem.

Any suggestions?

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**Author:** ![vlado](https://avatars.discourse-cdn.com/v4/letter/v/779978/32.png) [@vlado](https://forums.chaos.com/u/vlado)\
**Post date:** [June 19, 2008, 1:34pm UTC](https://forums.chaos.com/t/urgent-suggestions-needed-small-vraylightmat-objects-flickering/18472/2 "2008-06-19T13:34:10Z")

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Can you show a crop of a few frames?

Best regards,  
Vlado

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**Author:** ![re\_FORM](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/re_form/32/36295_2.png) [@re\_FORM](https://forums.chaos.com/u/re_FORM)\
**Post date:** [June 19, 2008, 1:39pm UTC](https://forums.chaos.com/t/urgent-suggestions-needed-small-vraylightmat-objects-flickering/18472/3 "2008-06-19T13:39:19Z")

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Will do… is it possible that using the DMC sampler is the problem? Initial tests suggest adaptive subdivision fixes the problem… although that’s just from rendering some stills, so there’s no guarantee that its fixed.  
Also… if it matters… I’m using Area AA. (I’m now testing without AA)

p.

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**Author:** ![re\_FORM](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/re_form/32/36295_2.png) [@re\_FORM](https://forums.chaos.com/u/re_FORM)\
**Post date:** [June 19, 2008, 1:40pm UTC](https://forums.chaos.com/t/urgent-suggestions-needed-small-vraylightmat-objects-flickering/18472/4 "2008-06-19T13:40:58Z")

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Yep. I can confirm the problem is fixed using no AA and Adaptive Subdivision sampling…

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**Author:** ![re\_FORM](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/re_form/32/36295_2.png) [@re\_FORM](https://forums.chaos.com/u/re_FORM)\
**Post date:** [June 19, 2008, 1:54pm UTC](https://forums.chaos.com/t/urgent-suggestions-needed-small-vraylightmat-objects-flickering/18472/5 "2008-06-19T13:54:38Z")

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Hmm.. I spoke too soon… flickering still visible.  
AND it looks like I didn’t have SubPixelMapping enabled… Switching on Sub-pixel mapping seems to stabilise the flickering.

My mistake 🙄