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MINI-TUT:How to use the new 2.3 v5 hotpixel tool effectively

PostPosted: Fri Oct 01, 2010 5:23 pm
by radiance
Hi guys,

The beta 2.3 v5 which was just released about an hour ago has a very handy new slider in the camera tonemapper's input pins/parameters,
which you can use to remove the fireflies or hotpixels as some call them very effectively, given the following advice:

1. Let your render finish, eg don't wait for all the fireflies to converge for hours, just do your ~20 minute unbiased (pathtracing, maxdepth = 1024) final render and wait until it's clean in terms of the amount of noise. (eg 3000 samples / pixel or more)

2. Pause the engine and open the camera tonemapper, and slide the firefly reduction slider lower until you're happy with the amount. If you have a final quality in terms of samples/px, eg 3000+), you should get a nice result with minimal smoothing if you slide it all the way down to 0, so just find the right level for your render. There are no real defaults as it depends on various things, your scene, light intensity etc...

3. save and post in the forums, or send to your customers ;)

Note that the more samples per pixel you have, the less smoothing you get when using a high amount of firefly reduction.

Attached an example of a final render, paused and then 2 shots of it taken, first one without the reduction (eg the slider is at 1.0 / right), the second with the reduction at nearly 0 (0.01).
The only issue remaining is unexplored caustics as you can see below the right front red chair, but the v6 will solve this with the new xxx algorithm which is nearly finished.

flies.jpg
without any firefly reduction


noflies.jpg
with reduction at 0.1


Yours,
Radiance

Re: MINI-TUT:How to use the new 2.3 v5 hotpixel tool effectively

PostPosted: Fri Oct 01, 2010 6:36 pm
by GeoPappas
Looks like a great feature.

But since the slider is called "fireflyreduction", I would have thought that increasing the slider (from 0 to 1) would have increased the reduction.

Re: MINI-TUT:How to use the new 2.3 v5 hotpixel tool effectively

PostPosted: Sat Oct 02, 2010 8:46 am
by DayVids
same here, you may want to reverse this slider or change it's name to more accurately reflect the way the control is used.

MINI TUT How to use the new 2 3 v5 hotpixel tool effectively

PostPosted: Sat Jun 20, 2015 10:12 am
by Joshuaowew
re-reading over the tut, does it save the new texture into something, or does it just make it there and then?

Re: MINI TUT How to use the new 2 3 v5 hotpixel tool effectively

PostPosted: Mon Aug 10, 2015 6:54 pm
by larsmidnatt
Joshuaowew wrote:re-reading over the tut, does it save the new texture into something, or does it just make it there and then?


typically you would save this new image. It does not change the source assets. if you want you could even disable the hotpixel tool and save a version that does not have this feature enabled. The hotpixel tool is non-destructive and can be turned on and off as you please.