Splotchiness in Animation Frames

[Michael J. Brown]

I hate even posting this, as I'm sure the solution is a simple one. Yet it is one which seems to have alluded me completely. I've read multiple methods of rendering flicker-free animations with moving objects in Vray, but because each varies slightly, selecting the one that's going to work for my scene becomes a challenge.

 

After much trial and error, I ultimately decided that I'll just composite the moving objects in my scene separately due to the render time that would have been needed to brute force 5400 frames.

 

But even after falling back to the tried and true basic fly-through method of pre-rendering every 15 frames (this is a very slow moving camera) while saving IRmap with LC set to flythrough, then rendering off the saved IR and having secondary bounces set to none, these are the results I'm getting. Should I uncheck "Use camera path"?

 

I've gone through multiple attempts to get this right and wasted an entire week doing so. Can someone offer some sound advice (detailed render setup settings) on how to get this right?

 

3dsMax Design 2014

Vray 2.4

 

note: The Light Cache settings displayed were for the pre-render phase. The final renders were run with secondary bounced set to 'none'.

 

Thanks much!

Edited March 4, 2016 by renderhaus

[Devin Johnston]

The splotches are coming from you IR settings, I'd set the preset to Medium-animation, subdivisions to 30 and Interp. samples to 150. Turn your light cache subs down to 500 and you may want to adjust your max DMC image samples to something much higher like 50. I've done lots of animations and those settings usually work, when you save out the GI you may want to use Animation-prepass instead of Multiframe incremental especially if there are moving objects in the scene. I realize it will take longer to save out the prepass but it will reduce the chances of GI artifacts.

[Michael J. Brown]

Thanks much, Devin.

 

Two questions:

 

1. Won't I need to prepass each frame (versus every Nth frame) with the Animation-prepass method?

2. Assuming I just leave my moving objects for a separate pass, would you recommend (after making the other adjustments) just leaving my GI method as Multiframe Incremental?

[Devin Johnston]

Yea you'd be rendering every frame for the prepass so if you think you can render out the moving elements separately and save that time then I'd do that.

[Michael J. Brown]

Thanks again!

[Michael J. Brown]

Devin, your solution worked out wonderfully on the precalc side. The splotches were eliminated and the pre-calc frames rendered very quickly. However, now my final render times are through the roof. Frames that should take no more than 35min are now taking 8 hours ea to run.

 

I've switched to the saved IR solution and turned secondary bounces off. Am I missing something?

[Devin Johnston]

8 hours seems pretty long, what's your noise threshold set at?

[Michael J. Brown]

8 hours seems pretty long, what's your noise threshold set at?

 

I had it overridden in the IR prepass at .002. I had left it there when running my (8hr) final renders.

 

I just switched it down to .01 and additionally scaled the max subdivs down from 50 to 4. These two things have lowered my render time to close to 3hr. Much better, but still unacceptable. I need these frames running at no more than 45min.ea.

[Devin Johnston]

There's all kinds of reasons why the render times would be that high, opacity mapped foliage, 3d displacement, IES lights could all be a contributing factor. Is the 3 hour per frame render time on the exterior or interior scenes?

[Michael J. Brown]

Interior.

 

- I'm using only 2D displacement mapping (I avoid 3D like the plague)

- No IES or photometric lights. (only Vray planes and daylight system with Vray sun)

- Foiliage does have opacity maps (Evermotion), but this scene is interior.

[Devin Johnston]

Sorry Michael I wish I had more magic tips to offer but I can't say why your render times are as long as they are. Sometimes in order to clear the GI noise you have to use these settings and just deal with the longer render times. One area that may be hurting you is the samples on your reflective surfaces, if your under sampling the engine will have to work longer in order to clear the noise.

[Francisco Penaloza]

Reviewing your first images, there is lots of glossy in your scene, those usually slow down renderings.

I also can see you have ON ambien occlusion, this also give you a little lag. mostly with a very low noise threshold.

If you are using displacement and LC, you need to increase your dynamic memory also check your RAM usage.

You could try to reduce the precision parameter on displacement too.

 

Other than that, you may need to debug item by item, to find what is producing the lag.

Maybe reduce your output size?? half HD would be fine, you could enlarge with Adobe encoder later to full HD.

 

You are in V Ray 2.4, that version of V Ray keep sampling on very bright areas ( this was a problems solved on V Ray 3.x) if you have very bright areas or object reflecting too much light ( white), you could try to use Reinhard with a burn of 0.4 or so. this will limit your dynamic range but will stop V Ray to keep oversampling on bright areas. You could use clamping at a value of 2. Those changes come with a sacrifice of dynamic range, if you are willing to accept that, it will help to render faster.

[jamesmacdonald]

You could re-calculate your light cache set to 'world' instead of 'screen'. Might help remove the blotches.

[Michael J. Brown]

I dropped my output to 720p (from 1080p), and bumped my noise threshold up to .035. Now I'm back down to a respectable 18min/frame

[Michael J. Brown]

Thanks all! I really appreciate your input.

 

What a great bunch of guys we have here