Animation (prepass) Flickering

V-Ray V-Ray for 3ds Max General
1

I have just rendered an animation with moving objects but the result has come out with alot of flickering and patchy anomalies.

I used Irradiance Map with Animation prepass but, these were rendered over a network to our render farm. Do you think that this might have caused the flickering and anomalies ?

Thanks

N

2

For SP2, there was a lot of additional flickering because the “time independent” option was forced to OFF during the calculation of the irradiance map (because the samples ended up completely different for each frame). This is corrected for SP3.

Best regards,
Vlado

3

Is SP3 available ?

4

Not officially yet; you can get a beta version if you email me to vlado@chaosgroup.com

Best regards,
Vlado

5

I have installed SP3 so thanks for that Vlado !

In relation to rendering an interior scene with lots of moving objects with no flickering - what are the best settings and process to achieve this ?

I have read the thread ‘Animation with GI that doesn’t flicker’ and must admit to being a bit confused as to specifically the best approach.

One option is the older method of using IRRAD/LC and pre calculating the Irradiance maps per frame with Animation (prepass) then switching to the Animation (rendering) before rendering. With the LC pre rendered once.

I did however read in the other thread that the LC should be rendered for each frame and stored with the LC - is this correct ? If so how is it done ?

Thanks for your help.

N

6

The correct way to handle this with the light cache is as follows:

Case I - “Use light cache for glossy rays” is OFF (the default)

Phase 1 - calculating the irradiance maps
1.1. Set the light cache to “Single frame”
1.2. Optionally turn off the “Store direct light” option for the light cache (might further reduce flickering around sharp shadows e.g. by the sun)
1.3. Set the irradiance map mode to “Animation (prepass)”
1.4. Render all the animation frames to produce an irradiance map for each frame

Phase 2 - render the final animation
2.1. Turn off the light cache (set secondary engine to “None”)
2.2. Set the irradiance map mode to “Animation (rendering)”
2.3. Optionally reduce the “Interpolation samples” to 10-15 and/or “Interpolation frames” to 1 to save render time
2.4. Render the final animation frames

Case II - “Use light cache for glossy rays” is ON

Phase 1 - calculating the irradiance maps
1.1. Set the light cache to “Single frame”
1.2. Optionally turn off the “Store direct light” option for the light cache
1.3. Set the irradiance map mode to “Animation (prepass)”
1.4. Render all the animation frames to produce an irradiance map for each frame

Phase 2 - render the final animation
2.1. Keep the light cache to “Single frame” mode
2.2. Set the irradiance map mode to “Animation (rendering)”
2.3. Optionally reduce the “Interpolation samples” to 10-15 and/or “Interpolation frames” to 1 to save render time
2.4. Render the final animation frames

The only difference in the two cases is that in Case I, you can turn off the light cache for the final rendering, whereas in Case II, you need to keep it to single frame.

Best regards,
Vlado

7

Fantastic Vlado - thanks !

8

Vlado, SP3 has solved the flickering which is great but, max crashes ALOT since I have installed SP3.

I cannot be certain that SP3 is causing it but, what I am certain of is that the crashes began after installation and they are severe crashes were max just disappears to the ‘Report crash to autodesk page’. Usually it would give the option to attempt a save of the file before closing.

9

Would be great if you email me to vlado@chaosgroup.com with more information about the particular situations where crashes are occurring.

Best regards,
Vlado

10

one question…

for this phase 1, may I produce the irradiance map over the network (that is using 5 or 10 nodes)? or should be produced only in one computer alone?

11

You can use network rendering for this; the irradiance maps for each frame are independent of one another and so they can be calculated separately.

Best regards,
Vlado

12

thanks! one last question.

that procedure is only to be used with SP3?

I’m trying with SP2 and is not working in the project I’m working with.

Best regards,

Carlos B.

13

Correct. SP3 only.

14

It should work in SP2 as well actually. Which part of it is not working?

Best regards,
Vlado

15

Ouf, sorry, did I miss something? I thought in SP2 the 2-pass-animation-mode doesn´t provide flicker-free animation?

16

Not completely flicker free in SP2, but it can be still useful, depending on the situation.

Best regards,
Vlado

17

Second phase, when I do my final render, the frames are not uniform, they are subtle changes in the shades, like if you were moving the light (but I not moving the light, I’m moving one object).

18

here you can see what it is the problem:

http://www.dreamimagecompany.com/NanoHouse/nanohouse.wmv

any help will be very appreciated.

Best regards,

Carlos B.

19

Wohu, this isn´t subtle. I would say this is the classical SP2 problem. Try to render the scene in still-image mode with high GI-settings. I know, sounds a little weird, but it works for me quite well. Rendertimes are kinda long…

If the GI´s quality is good enough it can provide a stable animation.

If you post the scene I would give it a try (Max 2008 only).

20

thanks a lot!

my bad luck, this is in 3ds max 2009

I will try your tip

best regards,

Carlos B.