VRay Flicker Free Animation Rendering - with Moving Objects

This post is is the process of being tested and will the content will reduced and condensed to have a full explanation once i have had a chance to test it all out.


- in case your animation has moving objects, you first have to calculate the IrrMap for all frames using the Animation (pre-pass) method, and only then you can render it using the Animation (Rendering) method. GI won't be any faster, but you can rest assured there won't be any flickering.

- but, if nothing moves in your animation but the camera (fly-through), you should set LC to Fly-through mode and the IrrMap to Multiframe Incremental. That will calculate GI a lot faster. Maybe not rocket fast, but helps.


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http://predmondvfx.wordpress.com/2012/04/17/vray-production-settings/


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I have rendered a lot of sometimes very complex lighting scenarios in Vray without any flickering at all, and it is extremely simple.

Use brute force as primary GI and light cache as secondary one. Make sure you do not use light cache for glossy reflections and that sudbdivs amount is around 2000 for fullHD resolution. Everything else at defaults, and AO disabled. Works perfectly every time.

I did stuff like an animated camera chasing a car moving through a dense CG forest, and it worked very well. I tried even intentionally complex lighting scenarios, but BF+LC just does not flicker, as long as you keep "Use LC for glossy reflections" off and your subdivs amount is high enough.


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I usually use following settings:
1, start with everything at defaults
2, primary GI brute force, subdivs 20, secondary light cache, subdivs amount same as larger side of rendered output - for example 1280 for 1280x720, or 1920 for 1920x1080
3, Adaptive DMC Min 1, Max 4,
4, Materials with glossiness 0.8-1 will have 8 glossy sudbdivs, materials with glossiness 0.6-0.8 will have 16 glossy subdivs, and materials with glossiness lower than 0.6 will have 24 glossy subdivs. Metal materials with low glossiness sometimes have 32, in cases where they get still noisy
5, subpixel mapping or clamp output is always off
6, always make sure you put your environment map into a full sphere VrayDome light... that light has usually 20-24 light subdivs. Other important lights in the scene usually have 16-20 subdivs, and smaller auxiliary lights have usually 4-8 subdivs.


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Nacho

Nacho Thomas

DMP/Environment TD at MPC

It depends mainly on the type of flickering you are having, and the kind of movement you are rendering. This is just a quick overview of the general type of issues you might find, and an intro to the best solution.

FLICKERING BLOTCHES (Procuced by an incorrect or insufficent Irradiance map)

There are three sort of situations you must identify.
1. Nothing (except camera) is moving. This is the easiest solution. A multiframe incremental calculation of the irradiance is perfect, wont produce any flickering, and is really quick to calculate.

2. A single object, or a small area moves. The rest is still. (Example, render of a car moving in front of a building). This case is based on the previous one. You hide the moving objects, and do the same than in step 1. Then, you unhide the moving objects, and use the cool "vrayspherefade" feature to calculate a frame by frame area which includes the moving objects, and its reflections, shadows, gi and refractions.

3. GI changes completely frame to frame. (Example, skylight moves---> GI changes). This is the method which requires a longer calculation. We do an "animation>prepass" to calculate the GI frame by frame, and then an "animation>rendering", caring about the "interpolation frames", which says the number of frames around the one we are rendering, that the irradiance map will load and average. Slow and memory consuming, but sometimes it is the best solution.

FLICKERING NOISE

There are some situations than cause noise in vray:
1- Area shadows.
2. Direct light from a dome etc. (Which in fact means the same as area shadows).
3. Materials with Reflections/Refractions with glossiness different to "1"
4. Brute force as regathering method (primary bounces)
5. An antialiasing not good enough
6. Camera subdivisions (when motion blur or depth of field).

There are mainly two ways of repairing flickering noise:
1. Pull up subdivisions of the parameter which is causing the noise.
2. Use a good antialiasing. This is always better, but much longer to calculate, as it checks every pixel in the image, instead of working just in the area where you get the noise. (I usually use adaptative dmc, min 1 max 6, color threshold of 0.005 (reasonable) to 0.002 (good quality), with VrayLanczosfilter to avoid the few noise left. 

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http://help.chaosgroup.com/vray/help/200R1/tutorials_anim2.htm

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http://www.workshop.mintviz.com/tutorials/flicker-free-animation-using-vray/

http://docs.chaosgroup.com/display/VRAY3/Rendering+an+Animation+with+Moving+Objects#RenderinganAnimationwithMovingObjects-Workflow

http://docs.chaosgroup.com/display/VRAY3/Rendering+an+Animation+with+Moving+Objects+II

http://www.workshop.mintviz.com/tutorials/flicker-free-animation-using-vray/