How to get rid of white sparks/'fireflies'

[Rchv]

I rendered this interior floor; it should be a slightly reflective (blurred) surface. But I get these white spots (at Luxrender they are called fireflies).

I set the Refelction value to a dark grey and Glosiness to 0.7, others default. What should I look at to prevent the white sparks?

PS using Vray/Blender fully for production and loving it.

[StompinTom]

Re: How to get rid of white sparks/'fireflies'

Crank up the Subdivs for that material's reflection and enabled Subpixel Color Mapping :P

[bdancer]

Re: How to get rid of white sparks/'fireflies'

Yep, material subdivs should be around 20-30 for 0.7 glossy.

[StompinTom]

Re: How to get rid of white sparks/'fireflies'

I've often had to put it up to 40-70 :P I think other settings impact it too, like your noise threshold in the DMC sampler. I'm still getting my head around certain settings and functionalities too!

Try using the Lightcache for glossy reflections too (in the Lightcache panel).

[bdancer]

Re: How to get rid of white sparks/'fireflies'

StompinTom, yep, all settings affects the result.

[tinmanjuggernaut]

Re: How to get rid of white sparks/'fireflies'

Also look at the filters in your image sampler. Play with the filters like area, catmulrom, lanczos, etc. Look in the manual for the difference. They can clean up artifacts a little bit or emphasize them depending on what look is desired.
Cory

[Rchv]

Re: How to get rid of white sparks/'fireflies'

Thanks all, I can see the result getting better by increasing the material Subdivs.

I then enabled 'use Light Cache' for glossy rays as StompinTom suggested and render time was almost 4 times as fast! Any comments?

[bdancer]

Re: How to get rid of white sparks/'fireflies'

I then enabled 'use Light Cache' for glossy rays as StompinTom suggested and render time was almost 4 times as fast! Any comments?

http://www.spot3d.com/vray/help/200R...s_lightmap.htm

Use light cache for glossy rays - if this option is on, the light cache will be used to compute lighting for glossy rays as well, in addition to normal GI rays. This can speed up rendering of scenes with glossy reflections quite a lot. When you use this option, it is recommended to also enable the Retrace threshold option, which will prevent the light cache from being visible in very glossy surfaces.

[Rchv]

Re: How to get rid of white sparks/'fireflies'

Use light cache for glossy rays - if this option is on, the light cache will be used to compute lighting for glossy rays as well, in addition to normal GI rays. This can speed up rendering of scenes with glossy reflections quite a lot. When you use this option, it is recommended to also enable the Retrace threshold option, which will prevent the light cache from being visible in very glossy surfaces.

I couldn't find the setting in my current Vray/Blender build 33205, but I see it is in the 2.56 build. (for the record in case someone else is looking for it)

Thanks for pointing it out, I recognize the artefacts from the Vray examples.

[bdancer]

Re: How to get rid of white sparks/'fireflies'

Rchv, this setting was from the very beginning... I only add Retrace option later.

[Rchv]

Re: How to get rid of white sparks/'fireflies'

Rchv, this setting was from the very beginning... I only add Retrace option later.

I ment Retrace only, indeed not Glossy rays.

[bdancer]

Re: How to get rid of white sparks/'fireflies'

Rchv, ah than its correct =)