GI TUTORIAL (PT4) - FLICKER-FREE ANIMATION + SCENE by STRAT

[STRAT]

OPTIMISED FOR VRAYforC4D 1.1


Other GI tutorials in the series:
PT1, GI camera animation - http://www.forum.vrayforc4d.com/showthread.php?t=1551
PT2, GI object animation - http://www.forum.vrayforc4d.com/showthread.php?t=2424
PT3, GI object animation, alt. method - http://www.forum.vrayforc4d.com/showthread.php?t=2888


This is part 4 in the series of GI animation tutorials. This slightly differs from the previous tutorials in that it's scene specific - i've provided the mesh and separate files containing all the render settings. It demonstrates the 3 main object animation techniques available in VRAYforC4D (brute force+light cache, irradiance map+brute force and irradiance map+light cache), which you should find fairly adaptable to your own scenes.
Object animation is where anything and/or everything in the scene moves over time other than the camera itself. This might include meshes, materials and lighting solutions. There are alternatives and workarounds to the methods outlined in this tutorial (as discussed in the previous tutorials), but this is the correct 'by-the-book' methodology.
The following examples and animations are pre-cached (where applicable) on a single oct processing mac pro (with 12 gig RAM), rendering 150 frames at 960 x 540 pixel resolution. Final rendering was done using a render farm as even though with VRAYforC4D 1.1 rendering is relatively fast these days, it's still comparatively slow where real scenes/deadlines are concerned. The use of a render farm is a common and normal procedure for the professional practise. Dont forget, whereas final render can nicely be performed over a render farm or a net render solution, the pre-caching must be carried out on a single computer.

Some of the results are pleasantly surprising.

A big thanks to the chaps and resources at Buzzbox ( http://www.buzzbox.eu/ ).
Thanks to Dann Stubbs at RenderKing ( http://www.renderking.com/ )
And thanks also for the usual top notch support from Stefan Laub and his team.


First off, here are the files you'll need -

http://www.leedavid.co.uk/temp/vray_tut04/model.zip - this is the scene. I've had to remove all textures as a lot of them are license bound to Buzzbox.eu and cannot be shared, but approximate colours have been assigned. It must also be noted that 1 or 2 items in the mesh are free downloads from the internet and are copyrighted to the original creators. The render settings are purely nominal (see individual files) and it's lit using the vray sun system and a couple of low light emitting omnis in the middle of the room, and be aware that due to the nature of the animation there are several keyframes attached to individual lights and objects (just in case you fancy playing and experimenting). There's also a spot of environmental GI thrown in for good measure.

http://www.leedavid.co.uk/temp/vray_...C_settings.zip - the C4D scene containing all render settings for the Brute Force + Light Cache render method Option 1

http://www.leedavid.co.uk/temp/vray_...F_settings.zip - the C4D scene containing all render settings for the Irradiance Map + Brute Force render method Option 2

http://www.leedavid.co.uk/temp/vray_...C_settings.zip - the C4D scene containing all render settings for the Irradiance Map + Light Cache render method Option 3

http://www.leedavid.co.uk/temp/vray_...t_settings.zip - the C4D scene containing all render settings for an optimised or 'best' version of the Irradiance Map + Light Cache render method Option 4

http://www.leedavid.co.uk/temp/vray_...89835-nice.zip - this is the IES file you'll need to assign to the single IES omni light in the Environment Null in each scene.



OPTION 1 - BRUTE FORCE + LIGHT CACHE

Movie Preview - http://www.leedavid.co.uk/temp/vray_tut04/BF+LC.mp4
Pre-cache time - n/a
Render time - around 7 hours
Total time - around 7 hours

Traditionally this is the preferred method for flicker free object animation, but due to the nature of brute force rendering, and the fact there's so much going on in the scene (including an animated sun), it takes a considerably long time to render out the scene. There is noticeable flicker in this render (ie, the book shelf shadow), but we deemed it acceptable. This type of flicker is due to too low a sample count in the DMC tab - i wanted to get the best clean (grain free) fastest render as possible, so sacrificing samples in the Global Subdiv Multiplier and lower Light Cache samples and sample size was required.

METHOD

1 ) BF and LC is a 'live' or 'on the hoof' render method, so no pre-caching is needed. Go up to the main OUTPUT tab and change the resolution to the full final anim size. Also save the image sequence to your liking.

2 ) In the vray tab, leave DONT RENDER FINAL IMAGE unclicked

3 ) AA: the Parzen filter is used in this instance, with fairly fine aDMC settings ((or try Welch filter, with a value between 1.3-1.5 for less flicker again. Thanks Fluffy)

4 ) DMC sampler: adjusted to suit AA settings and BF sample count.

5 ) In the GI tab, prims set to BF and seconds to LC. The BF settings are set to 40 and LC is SD=1650. I also turned off any LC filters and pre-filters. mode is SINGLE FRAME.

6 ) Hit render again. Your final animation should now render with (hopefully) no or minimum gi flicker.



OPTION 2 - IRRADIANCE MAP + BRUTE FORCE

Movie Preview - http://www.leedavid.co.uk/temp/vray_tut04/IR+BF.mp4
Pre-cache time - 9 hours 45 mins
Render time - around 4 hours
Total time - around 14 hours

Considerably slower in complete render/set up time, but the results are a lot cleaner with less flicker than the BF+LC method. Again, this 'slower' time is due to the BF secondary bouncing.

METHOD

1 ) Render the IR map off. Go up to the main OUTPUT tab and change the resolution to 2/3 the size of the final resolution (1/2 might be passable, and full res would obviously be best, but 2/3 works good) and click on ALL FRAMES, but dont save anything.

2 ) In the vray tab, click on DONT RENDER FINAL IMAGE.

3 ) Switch off all AA, and leave the dmc sampler as it is.

4 ) In the gi tab, turn on Refractive in the GI Caustics, change prim bounces to irradiance and secondaries to brute force. The irradiance settings are: min/max= -3/-1, HS=100, IS=30, IF=4, IT=0.3, NT=0.1, DT=0.3, set mode to ANIM PREPASS, and check the AutoSave button on Render End. Save the maps as, for example, PP_

5 ) The brute force settings are 8 and 8

6 ) Hit render. It'll then render every frame off for the IR, at two thirds size. This might take a fair bit of time, so if you want to lower any of the said settings then please to so, but you'll then be more and more open to flicker.

7 ) Once rendered, change the OUTPUT resolution back up to full size, type on a name to save your image sequence and turn off DONT RENDER FINAL IMAGE.

8 ) Turn on AA, (see settings in file)

9 ) Change the IR mode to ANIM RENDER, then copy the name of the first file below into the LOAD FILE box. Switch off AUTO SAVE. Leave BF as it is.

10 ) change the INTERPOLATED FRAMES to 2. In my examples, a higher value slowed down rendering and lessened the gi effect.

11 ) hit render again. Your final animation should now render with (hopefully) no or minimum gi flicker.



OPTION 3 - IRRADIANCE MAP + LIGHT CACHE

Movie Preview - http://www.leedavid.co.uk/temp/vray_tut04/IR+LC.mp4
Pre-cache time - 4 hours 10 mins
Render time - around 2 hours
Total time - around 6 hours

A dramatic drop in total render/set up time. VRAYforC4D 1.1 delivers a much improved IR/LC pre-cache time and quality of previous versions. This is now my preferred object animation render method, both in render time and quality. There is a very slight GI flicker in the animation, but hardly noticeable and not even worth mentioning.

METHOD

1 ) First, pre-cache the GI solutions. Go up to the main OUTPUT tab and change the resolution to 1/2 the size of the final resolution (2/3 to full size would be better, but not generally needed) and click on ALL FRAMES with Frame Step at 1, but dont save anything.

2 ) In the vray tab, click on DONT RENDER FINAL IMAGE.

3 ) Switch off all AA (although not essential), and leave the dmc sampler as it is, however to minimise or avoid grain swim you should turn the Time Dependent option to OFF.

4 ) In the gi tab, turn on Refractive in the GI Caustics, change prim bounces to irradiance and secondaries to light cache. The irradiance settings are: min -3, max -1, hemsubs 100, inters 30, int.threshold 0.3, norm.threshold 0.1, dist.threshold 0.3, set mode to ANIM PREPASS, and check the AutoSave button on Render End. Save the maps as, for example, PP_

5 ) In the Light Cache tab, the light cache settings should be Sub-divs to 1250, leave Scale on Screen and leave the samples at 0.02. (it's only a short camera pan, so Screen mode is fine)
For best results, click on the Adaptive Tracing and Use Direction Only boxes.
Very importantly, click on Store Direct Light. This bakes the LC solution into the cached IR map.

Render mode is SINGLE FRAME

6 ) Hit render. This will now render the IR + LC solution of every frame, at half size. Sounds a lot, but on a single mac pro this is averagely 2-3 mins per frame.

7 ) Once rendered, change the OUTPUT resolution back up to full size, type on a name to save your image sequence and turn off DONT RENDER FINAL IMAGE (ie, un-tick it).

8 ) Turn on AA, (settings as per file example)

9 ) Change the IR mode to ANIM RENDER, then copy the name of the 'Save as' file into the 'LOAD FILE' box. Switch off AUTO SAVE.

10) In the Secondary Bounces box, turn it to NONE. The light cache was baked into the irradiance solution in step 6.

11 ) Change the INTERPOLATED FRAMES to 2. In my examples, a higher value slowed down rendering and lessened the gi effect.

12 ) Hit render again. Your final animation should now render with (hopefully) no or minimum gi flicker.



OPTION 4 - IRRADIANCE MAP + LIGHT CACHE [BEST SOLUTION]

Movie Preview - http://www.leedavid.co.uk/temp/vray_...IR+LC_best.mp4
Pre-cache time - 7 hours
Render time - around 2 hours
Total time - around 9 hours

After rendering the above example using Irradiance Map and Light Cache, which proved the best in both quality and render speed, i decided to optimise the file a bit further to produce an even greater finish of flicker free render quality. The render pre-cache time is a bit longer, but well worth the sacrifice.

METHOD

1 ) First, pre-cache the GI solutions. Go up to the main OUTPUT tab and change the resolution to 1/2 the size of the final resolution (2/3 to full size would be better, but not generally needed) and click on ALL FRAMES with Frame Step at 1, but dont save anything.

2 ) In the vray tab, click on DONT RENDER FINAL IMAGE.

3 ) Switch off all AA (although not essential), and leave the dmc sampler as it is, however to minimise or avoid grain swim you should turn the Time Dependent option to OFF.

4 ) In the gi tab, turn on Refractive in the GI Caustics, change prim bounces to irradiance and secondaries to light cache. The irradiance settings are: min -3, max -1, hemsubs 125, inters 35, int.threshold 0.5, norm.threshold 0.1, dist.threshold 0.5, set mode to ANIM PREPASS, and check the AutoSave button on Render End. Save the maps as, for example, PP_

5 ) In the Light Cache tab, the light cache settings should be Sub-divs to 1500, leave Scale on Screen and leave the samples at 0.02. (it's only a short camera pan, so Screen mode is fine)
For best results, click on the Adaptive Tracing and Use Direction Only boxes.
Very importantly, click on Store Direct Light. This bakes the LC solution into the cached IR map.

Render mode is SINGLE FRAME

6 ) Hit render. This will now render the IR + LC solution of every frame, at half size. Sounds a lot, but on a single mac pro this is averagely 3-4 mins per frame.

7 ) Once rendered, change the OUTPUT resolution back up to full size, type on a name to save your image sequence and turn off DONT RENDER FINAL IMAGE (ie, un-tick it).

8 ) Turn on AA, (settings as per file example)

9 ) Change the IR mode to ANIM RENDER, then copy the name of the 'Save as' file into the 'LOAD FILE' box. Switch off AUTO SAVE.

10) In the Secondary Bounces box, turn it to NONE. The light cache was baked into the irradiance solution in step 6.

11 ) Change the INTERPOLATED FRAMES to 4. In my examples, a higher value slowed down rendering and lessened the gi effect, and less gave more flicker. You might get away with 2, but 4 ensured a better finish.

12 ) Hit render again. Your final animation should now render with no or minimum gi flicker.


As can be seen, out of the main object animation methods the Irradiance Map + Light Cache solution seems to give the most pleasing results. As mentioned, these settings should be easily adaptable to suit your own needs, but each scene is individual and needs individual attention.
There is no 'best setting', but Vray's defaults are very adaptive and the more understanding you obtain yourself the better your rendering will end up.

[stefan]

thanks a lot STRAT!

these look very good, a perfect overview over all available methods:-)

cheers
Stefan

[Rich_Art]

Great STRAT.. Thank you very much.

Peace,
Rich_Art. :wink:

[colibert]

thanks strat..am going to need these tuts very soon!

looks very thorough and well done

[ZFact]

GOOD MAN!

[machmirdenlukas]

thanks for your effort!
cheerz rob

[Cian]

Sweet. Thanks Strat.
Much appreciated.

Cian.

[belushy]

thanks for providing such usefull test and solutions

[ollie]

Dear Strat,

many thanks for the files include the settings!!!

Ollie

[choppir]

goodness mate.

You are awesome!

Thanks man. Will check it out!

laters

Choppir