Neon Sign - Part 2 - Rendering

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Finally got around to shading and rendering this project. As before, I recorded a time-lapse of the entire process as a pseudo-tutorial. Check it out here if you're interested:

https://vimeo.com/125116427 [vimeo.com]

Attachments:
WhiteHavenNeon_C28_900.jpg (282.5 KB)
WhiteHavenNeon_C01_900.jpg (235.5 KB)
WhiteHavenNeon_C03_900.jpg (188.2 KB)
WhiteHavenNeon_C13_900.jpg (229.3 KB)
WhiteHavenNeon_C37_900.jpg (259.9 KB)
WhiteHavenNeon_C00_900.jpg (268.0 KB)

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Looks great Keith, thank you!
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Nice Keith! A Houdini master in express-time!
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great work!
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awesome videos Keith.

Thanks for taking the time to make them.
Werner Ziemerink
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Thanks guys. Having fun with Houdini.

Werner - thanks! Glad you find the videos useful.
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There was a question on the vimeo comment board about render settings, so I thought I'd elaborate a bit here.

Renderer was PBR, and after tweaking render parameters in a bracketing/wedge fashion, I found the two most important variables in achieving quality versus speed were the pixel samples and noise level. Those are the main numbers I tweaked to flip between a low-quality/fast preview render and the hi-quality final render. The other variable that's a bit hard to quantify, was that I had to increase the shading quality on a few key pieces of geometry (I did this on a per object basis - bumping it up from the default 1 to something around 3-4). As I state in the video, this was mainly to fix what looked like an odd dicing error on large n-gons that were utilizing gridded bump maps to simulate panel seams.

As for the other settings - I found a law of diminishing returns kick-in with the Max Ray samples. It appeared anything over a value of 6 did little to the render. Also, on the limits tab, it was important to keep the Reflect, Refract, and Diffuse numbers as low as possible. Any values above 2,2,and 1 respectively, achieved only a minor bump in quality, but a huge increase in render times. So that's basically the unscientific way I arrived at my render settings! Screenshots for both the low-quality and final-quality settings are attached.

I found with low-quality settings, interactively tweaking the shading and lighting was pretty good…at least good enough for me to move forward without getting frustrated. As I state in the video. With the final quality setting, rendering at 2000 x 2000, the rendertimes were generally around 8 hours. This is on a 2nd generation i7 machine, capable of turboboost above 3 GHz with 12 gb ram. One thing I did notice is that my machine was very rapidly using up ALL of the ram with no headroom, so I imagine it would be a good thing to upgrade that. Thankfully, Mantra does not just crash on you when you hit the ram ceiling, like V-Ray used to be notorious for. Still, 8 hours for a 2000x2000 render seems a little steep. And it still may have been too noisy for animation. This didn't bother me for a small test project, but it could be an issue later if I do full animation work for a production.

Really though, the speed was my only gripe. Mantra was incredibly stable, reliable, and predictable. I don't think I had a single crash or freeze while working with the interactive render, and the dicing error I stated above was the only unexpected surprise that required troubleshooting.

Attachments:
MantraSettings_LowQuality.jpg (123.8 KB)
MantraSettings_FinalQuality.jpg (128.2 KB)

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in these post there are some tips for the rendering speed up's the 9 hours i find are very long:

http://forums.odforce.net/topic/16507-corona-render/page-2#entry101045 [forums.odforce.net]
http://forums.odforce.net/topic/22080-suppress-small-artefact-in-pbr-render/ [forums.odforce.net]

btw. a absolutly nice job you have done… :-)
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EDIT - renders are looking really good…

I think your settings can be adjusted. I think your noise settings are too extreme and your min and max ray samples too low, and I think you can probably turn stochastic transparency off.

I can still see noise under your neon lights that I think will clear up with the min max ray samples. For final quality I often start right around here

Pixel samples = 3 X 3 to 5 X5 - tune up but start at 3 X 3
Min Ray samples = 2
Max Ray samples = 12 ( Sometime it goes up to 18)
Noise level = .02 (I have seen in a post that this is less then the grain we would get from standard film)

I think that also…

You can increase your diffuse bounces to 2 or 3 - I don't see much of a time hit here in my testing, some but not much

Color limit = 5

Mantra is slow, but not that slow. I have certainly done production rendering at even larger sizes much faster than that.

Hopefully Redshift which I use in Maya will be available for Houdini soon, as that renderer is super nice and wicked fast…
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Nice! Thanks for the rendering tips guys. I have no doubt I can get these render times lower. With time I'll have a better feel for it.
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wow - nice work!
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Nice!
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What happened to the videos Keith? It seems they were taken out of the air.

That was really a awesome reference that I was trying to show to my Houdini migrating friends.
http://www.vimeo.com/17790588 [www.vimeo.com]
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There's a copy on YouTube:
https://www.youtube.com/watch?v=BpdO6vjU_24 [youtube.com]
https://www.youtube.com/watch?v=r0o09mpUnvo [youtube.com]
Andrew
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Thanks for the links, there is also a 3rd part 3rd part [youtube.com]
But this is just the modeling part it is missing the render part, which is really a shame it is a awesome result.
http://www.vimeo.com/17790588 [www.vimeo.com]
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mzigaib
Thanks for the links, there is also a 3rd part 3rd part [youtube.com]
But this is just the modeling part it is missing the render part, which is really a shame it is a awesome result.

You're right, didn't notice there was the render part too.
It seems all the links around are pointing to the same Vimeo account.
Too bad there isn't a copy of those on YouTube.
Andrew
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Nice, but I cannot seem to be able to open the video anymore. Can you repost it?
My work, both pro and personal….
https://vimeo.com/nicolashe [vimeo.com]
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Hi Keith,

I got loads out of your tutorials and was really interested in the one that you did with the pendulum wave, which I always meant to go back to look at at a later date, but then discovered had disappeared. Is this something you might repost at some point? I really enjoyed the way you'd explain your whole process beginning to end, including the source of your inspiration. Thanks for putting them up in the first place, in any case
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