# Flickering Reflections

**URL:** <https://forums.chaos.com/t/flickering-reflections/17105>\
**Category:** Issues\
**Created:** [February 15, 2008, 7:15pm UTC](https://forums.chaos.com/t/flickering-reflections/17105 "2008-02-15T19:15:04Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![Dmerc](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/dmerc/32/69792_2.png) [@Dmerc](https://forums.chaos.com/u/Dmerc)\
**Post date:** [February 15, 2008, 7:15pm UTC](https://forums.chaos.com/t/flickering-reflections/17105/1 "2008-02-15T19:15:04Z")

</div>

We are working on a movie presentation right now, and as you can see in the sample-movie, we have a problem with flickering reflections. At some points the edges of these lights are pretty jagged as well.

[www.xoio.de/public/flackern.mov](http://www.xoio.de/public/flackern.mov)

Subpixel mapping is ticked on.

The reflected pseudo-lights are in fact cylinders in the ceiling with a vray-light material and a strong multiplier of 10+ to make them highlight strongly on the carpaint gi-output turned off). This is, because we have to show tons of these downlights, so the reflections are impossible to do with regular lights.

I would guess it is a antialiasing problem, but I am not very good at this: We are using adaptive subdivision with a 1.5 area filter.

How could you get around this and have the edges antialias properly ?

BTW, since we are doing this for animation-purposes we can’t afford exploding rendertimes 😉

Thanx for your help in advance, Peter

---

<div class="post-metadata">

**Author:** ![percydaman](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/percydaman/32/42214_2.png) [@percydaman](https://forums.chaos.com/u/percydaman)\
**Post date:** [February 15, 2008, 7:35pm UTC](https://forums.chaos.com/t/flickering-reflections/17105/2 "2008-02-15T19:35:10Z")

</div>

saying you use adaptive subdivision without mentioning the sample settings isn’t super helpful. Also, which can you least afford, poor/flickering reflections, or longer rendertimes?

---

<div class="post-metadata">

**Author:** ![Dmerc](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/dmerc/32/69792_2.png) [@Dmerc](https://forums.chaos.com/u/Dmerc)\
**Post date:** [February 15, 2008, 8:27pm UTC](https://forums.chaos.com/t/flickering-reflections/17105/3 "2008-02-15T20:27:52Z")

</div>

Antialiasing settings:

Hmm, alright. True. As I said I never dared to play with these too much:

a) settings are:

Min -1  
Max 2  
Color threshhold 0,1  
No outline  
no normal threshhold  
yes randomize samples  
obviously not show samples

b) Considering Rendertime:

Well, you know, it’s never an A or B solution. It would definitely hurt, if rendertimes would double, but we could spare another couple of seconds.

Is adaptive sampling the right solution for animation purposes anyhow or would I choose another ?

Thanx in advance and have a nice weekend !

Cheers, P

---

<div class="post-metadata">

**Author:** ![percydaman](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/percydaman/32/42214_2.png) [@percydaman](https://forums.chaos.com/u/percydaman)\
**Post date:** [February 16, 2008, 2:39am UTC](https://forums.chaos.com/t/flickering-reflections/17105/4 "2008-02-16T02:39:19Z")

</div>

-1,2 is sufficient for animation I’m afraid. 0,2 or even 0,3 would help your problem. Sometimes adaptive DMC AA can do a better job. i’d recommend taking a look at the manual. It would explain it better then I could.

---

<div class="post-metadata">

**Author:** ![Morbid\_Angel](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/morbid_angel/32/21272_2.png) [@Morbid\_Angel](https://forums.chaos.com/u/Morbid_Angel)\
**Post date:** [February 16, 2008, 8:13am UTC](https://forums.chaos.com/t/flickering-reflections/17105/5 "2008-02-16T08:13:01Z")

</div>

undersampling is not a good idea for final renders…ever.  
My recomendation for you, when rendering with hot specular/reflection highlites to use a higher aliasing, something like 1/2, or 1/3 for adaptive subdivision.  
For adaptive dmc, 1/16 or 1/24 with noise threshold of 0.004 should do the job.

---

<div class="post-metadata">

**Author:** ![Dmerc](https://dub1.discourse-cdn.com/chaosprd/user_avatar/forums.chaos.com/dmerc/32/69792_2.png) [@Dmerc](https://forums.chaos.com/u/Dmerc)\
**Post date:** [February 16, 2008, 1:05pm UTC](https://forums.chaos.com/t/flickering-reflections/17105/6 "2008-02-16T13:05:23Z")

</div>

Regards

I thank you kindly, and will try the adapted settings asap !

Best regards, Peter