VueRealism.Com: Trees and GI - Flicker Elimination RC

I set out on this challenge due to an animation problem
I was having with the flickering of trees in the distance.
At the time I was using GI, and was looking to seek out
and destroy my problem. I'm also using this test to get
a better feel for the effect breeze has on trees.
Many thanks to those who have helped me along the way.

So, lets start with the scene info that DOES NOT change
during the course of the trials.

---- GI Lighting (+0.40, 55%, 50%)
---- Ambiance: .30 Sky Dome Gain: .85

---- User Render Settings (loaded Final and edited)
---- OAA (9,9) = 69%
---- TAA (4,16) = 85%
---- Adv Efx Qual: 46%

---- Wind Disabled
---- TGA Sequence

TREE01: http://www.vuerealism.com/renderchallenge01/tree01.wmv (1 MB)
Here are the edited parameters:

---- Quality boost = -1.0
---- Breeze enabled (30% intensity)
---- Ignore Indirect Lighting on Plants UNCHECKED
---- Rendered at 5.06 Minutes Per Frame

What we see here is quite a bit of flickering going on. This has to do with the GI setting being set too low. There seems to be not enough precision in the GI, thus this must be increased. Philippe Bouyer, Vue 5 Infinite animation guru, states that he believes GI should be increased to +2.0 or +3.0. To keep render time down, I'll try the next round with +1.0.

TREE02: http://www.vuerealism.com/renderchallenge01/tree02.wmv (2 MB)
Here are changes made after TREE01 to the parameters:

---- Quality boost = +1.0
---- Breeze enabled (40% intensity)
---- Rendered at 11.03 Minutes Per Frame

As we can see, boosting the GI to +1.0 did in fact help, but wow. We're talking a bit more than double the processing time as -1.0. In an effort to keep the rendering time down a bit, for the next run, I'll reduce the GI back to -1.0 and see what effect checking on Ignore Indirect Lighting on Plants has on the render as that could also be a source of the problem. I like the amount of breeze that there is this time so I'll leave it at 40% for the rest of the trials.

TREE03: http://www.vuerealism.com/renderchallenge01/tree03.wmv (2 MB)
Here are changes made after TREE02 to the parameters:

---- Quality boost = -1.0
---- Ignore Indirect Lighting on Plants CHECKED ON
---- Rendered at 5.11 Minutes Per Frame

Well, the flicker is back. It is indeed the GI setting that is causing a major amount of this flickering. The only change I really noted between TREE03 (IILOP on) and TREE01 (IILOP off) was on the trunk of the plant, which in TREE01 added some flicker to the animation. Another interesting point is that the rendering time with IILOP on and off was virtually no different. If you are concerned with reducing flicker, I would turn this option off.

However, while I now know +1.0 will help with the lighting's consistency, I still am not a fan of how the edges of the leaves are flickering a bit. This likely has to do with my OAA being set at 9/9 (still not sure how this happened as I did not edit it). For the next run, I will try to increase this and get away with a GI boost of 0.0.

TREE04: http://www.vuerealism.com/renderchallenge01/tree04.wmv (2 MB)
Here are changes made after TREE03 to the parameters:

---- Quality boost = 0.0
---- OAA (6,24) Threshold (85%)
---- TAA OFF
---- Rendered at 3.2 Minutes Per Frame

The results of the higher OAA settings were good, but at 0.0 the GI was still not consistent enough. You do need higher settings. I turned off TAA for this render as well and got a lot nicer rendering times with very little trade off in quality. What I'm learning most through the process is just listen to Phoul. Haha.

TREE05: http://www.vuerealism.com/renderchallenge01/tree05.wmv (2 MB)
Here are changes made after TREE04 to the parameters:

---- Quality boost = +1.0
---- Rendered at 3.75 Minutes Per Frame

With TAA off, I noticed the rendering hit for the increased GI was a lot more manageable. A boost of 1.0 works, there is no noticeable flickering.

So, a final sum up:

**To eliminate flickering on vegetation in a GI animation:
**

1. Decrease the highlights of the tree/plant's leaves. This helps mostly in the distance but can be key. Make sure you save it in the plant editor as a new .VEG file so that you maintain all the benefits of a VEG file.

2. GI Boost of +1.0 or higher is absolutely necessary. I did not test above +1.0, so I'm not sure how much it improves past +1.0, but I was pleased with +1.0.

3. Turn ON Ignore Indirect Lighting on Plants.

4. Set Object Anti-Aliasing at (6 min/24 max) and at least 85% threshold. Phoul suggests 95% threshold for slow camera movement. Seeing as how everything I did ended up how he said, I'm just going to assume he's right.

5. Turn OFF Texture Anti-Aliasing.

I hope you guys got something out of this. Sometimes, even tho a guru such as Phoul tells me something, I still need to see it before my eyes before I truly "get it". Maybe this helped some of you "get it" a bit better. I know that most people simply don't have time to conduct studies like this. I hope that's what VueRealism.Com will eventually provide.

• Ryan Spaulding (megaphors_rs@yahoo.com)
  VueRealism.Com

Fanstastic work. Thank you for the insight. Great improvement in the final render.