Author Topic: Graininess in Shadows.  (Read 3503 times)

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Offline Doc

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Graininess in Shadows.
« on: November 29, 2017, 05:49:02 am »
Good Morning!

I'm creating an animation for my company describing one of our products.  There are 1321 frames at 12 fps, roughly 1 min 50 sec, so you can see I'm trying to reduce the render time by as much as possible.  I'm well aware it will take some time to get the quality I need and am trying all different types of adjustments to get the quality without having to render for a few weeks.

Work PC specs :
8 core Intel i7-6700 3.40 GHz
32 GB RAM
AMD Radeon R7 350X 4GB

Interior lighting settings have already helped with the speed drastically and now I'm trying to adjust the sample rate by material vs global.  The outside of the valve looks absolutely fantastic, but then when its sectioned is where the problem lays.  The example image attached is set at 50 samples globally and 100 samples per affected material on the inside of the valve where the shadows are. This has reduced the render time from 80 frames in 24 hours to 800, but sacrificed quality (Only to the shadows).

Previously, I had the default lighting settings and default material samples at 16.
 The global samples were cranked up to 150-200.  This originally was to reduce the grains in the blue plastic knob at the top of the valve and the white washers on the inside, shadows had no problem.  Switching over to "Interior" mode greatly benefited the materials stated before, but now the shadows are showing much more grain.  I tried switching back to basic lighting settings and just increasing the material sample on the thrust washers and blue plastic control knob, however the drop down under roughness for sample rate is not there.

The material sample rate stops at 100, correct?  Although, I can bring up the global sample rate well above that, this will greatly increase render time.  My main question is, am I in a situation where global sample rate increase is my only option?

I've tried adding a light in the environment to get rid of some shadows but that washes out a lot of the steel material, it makes the material too bright without actually brightening up the shadows enough to make a difference.  I've reduced the frame rate and the aspect ratio.  I've increased shadow quality in the lighting settings and increased the ray bounces, messed with global illumination and self shadows, etc.  The material sample rate seems to not make an impact in the shadow quality.

Any advice would be greatly appreciated.  I apologize for the wall of text   :)

-Doc

Offline mattjgerard

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Re: Graininess in Shadows.
« Reply #1 on: November 29, 2017, 06:22:18 am »
I am replying to this so I can track the responses as well, as I'm interested in this info too. I do know that using actual lights in the scene increases render times, so sticking with HDRI lighting if you can will cut that down. From waht I hear, 98% of the time with product images, HDRI lighting and using the HDRI editor (if you have it) will get you where you need to be without using actual lights.

My second point is that for something like this you might consider using a render farm? If you have some sort of budget to work with that might be a way to go. When you calculate the time savings vs the cost, it really can be a smart choice. We decided to try the Network render option first before going to an external farm, and our productivity between the 2 artists here went waaaaaay up since we can offload the renders and keep working on the next project. Honestly the render machine we have is actually slower than my local machine, but just being able to offload the render and not tie up my machine is a huge timesaver and moral booster since I'm not sitting there twiddling my thumbs waiting for my machine to finish.

Images look good though!

Offline Doc

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Re: Graininess in Shadows.
« Reply #2 on: November 29, 2017, 06:49:09 am »
Thanks for the reply and the compliment!

I've presented the idea of a render farm to my superiors and it was taken well.  If there is a time crunch or similar situation, it is always good to know you can send your work over to get it rendered in a fraction of the time and at a reasonable cost.  I've also raised concern that if I'm rendering in real time and using all 8 cores, I won't be able to multi-task with SolidWorks or any other software to benefit my time.  So maybe a second machine or laptop will be in the works.

I'm glad to hear that the path to resolve this problem seems to be the correct one.  As for lighting, when adding the light, I was referring the the HDRI editor (fantastic feature).  Thank you for catching that clarification. 

Offline Esben Oxholm

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Re: Graininess in Shadows.
« Reply #3 on: November 29, 2017, 07:28:20 am »
Hi Doc.

When having noisy dark areas like this, I've experienced that using the advanced rendering mode can be good to use instead of the maximum samples, which I assume you use at the moment?

It'll take some more time to find the sweet spot between time and quality, but usually I can get rid of the noise this way without having longer render time.

Cheers,

Offline Doc

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Re: Graininess in Shadows.
« Reply #4 on: November 29, 2017, 07:47:31 am »
That is correct, Esben, and that is really what this boils down to, finding that sweet spot.  Just trying to get a general consensus if I'm approaching this issue correctly and on the right track to getting to where I'd like to be.  This animation is almost finished so I'll try a few more little tweaks and start at a later frame to see if I can get rid of that grain without sacrificing too much time.  Also, I don't mind running my machine for a week if thats what it takes, but if I can avoid that then it would benefit everyone here.

1300 frames finishing in just under 24 hours is already a leap to where I was the other day, so progress is being made.

Thanks for your input!

Offline Robb63

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Re: Graininess in Shadows.
« Reply #5 on: November 29, 2017, 04:46:21 pm »
I didn’t notice you listing this your text, but what pixel resolution are you rendering this at? There doesn’t seem to be anything here from a material standpoint that would create such long render times.
One thing I do is break my animations up into groups. I never let Keyshot render any pauses in the animation. Any still (paused) frames I use After Effects to create. Saves me tons of time.

Offline JRR_render

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Re: Graininess in Shadows.
« Reply #6 on: November 30, 2017, 07:43:20 am »
I am posting a similar question within this board because I think I have a similar issue.  I'm still very new to Keyshot and have a lot to learn.  I am seeing a graininess/blotchy shadowing behind the glass when I render this light fixture.  I gladly welcome suggestions on how to improve my work.

Offline mattjgerard

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Re: Graininess in Shadows.
« Reply #7 on: November 30, 2017, 09:58:33 am »
I am posting a similar question within this board because I think I have a similar issue.  I'm still very new to Keyshot and have a lot to learn.  I am seeing a graininess/blotchy shadowing behind the glass when I render this light fixture.  I gladly welcome suggestions on how to improve my work.

This could be a couple of things, might be best to create a fresh thread for your specific question. Easier to track, search and reply. But right off the bat we would need to know if you are rendering in interior mode, if so, it takes a while longer to resolve those blotches. try product mode first, its faster and most of the time unless its in an enclosed space is perfectly acceptable for this sort of thing. Next is to troubleshoot the textures, geometry, lighting, etc. If you can post the scene that makes it all the easier.

Offline JRR_render

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Re: Graininess in Shadows.
« Reply #8 on: November 30, 2017, 11:05:48 am »
Thanks Matt.  I didn't save the scene as I've just been playing around with it, but I think I was using the interior preset.  For next time, how do you suggest I post a scene for troubleshooting?

Offline mattjgerard

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Re: Graininess in Shadows.
« Reply #9 on: November 30, 2017, 11:33:58 am »
You can save it out as a package (in the file menu, Save as Package) and if its small enough you can upload it directly to the forum when you create a post. I think its a 50mb max. otherwise use a dropbox type service and share the link. Saving it as a package will zip together all the HDR's, textures and other hard assets connected to the project.