I’m very interested in new to me Corona renderer. I’m doing a little clip of future interior with animated things like robots and furniture. Usually we’re using V-Ray for our works but for this clip with lots of animation (usually we’re have only people and cars moving in exterior scenes or just people in interiors). I found that Corona is great for animation and started to do animation with it.
During the previsualization I found a little strange thing with flickering the secondary GI named “HD cache” (it’s not about the noise, but flickering of whole lighting of secondary GI). As you can see in attached file default settings (top video) of Corona flickering is quite pronounced. Of course I’m started to find the problem. And it was the parameter “Refl glossiness threshold”. In default settings it has a value of 0.9. With this value it produces a cleaner image in blurry reflections, but in expense of flickering as I found. I don’t know if it’s right, but in my tests it is. Then I set “Refl glossiness threshold” to value 0.08 and render animation preview with it. As you can see at bottom video the flickering is much less pronounced in movie then with “Refl glossiness threshold” 0.9, but still there.
May be I’m doing something wrong and you know the way to turn this flickering down?
reflection glossiness threshod disables HD cache for too specular objects. It seems you have probably disabled it for most of the scene in the second case. You can confirm by comparing the HD success rate % in the statistics in VFB between the two renders. The current best solution is to save and reuse the cache (save/load secondary GI option)
Yea. This seem to work with fly-through animation without moving elements, but with our animation full of moving subjects and turning lights on and off it is unusable as I see. I’ve tryed to save HD cache for first frame and reuse it in animation but it feels like all the lights bounces has gone for secondary GI.
In attachment you can see frame with saved HD cache (on left) and with computed during render (on right).
Wow! It seems that it works for this scenario. It doubles rendertimes, but 40 sec of 57 sec of render was the preparation of Secondary GI (HD cache ia mean), so I hope with final render it will be almost no cost (if it will not scales with final quality).
Update:
For the final quality (720p) HD cache was computed in 2:30 min. Super. I’ll post final quality report a bit later and full clip in gallery as it will be done.
Yes, it works, but with outdated lighting information in the secondaries. As soon as your light moved, your primary (pt) bounces are still calculating with the secondaries information of where the sun was before. So if you really push the limits (e.g. a full day circle) you will easily see things getting weird.
I had movement from midday to evening in two 5second animations. I saved HD cache (computed 8192) without any issue.
I had few issues with reflections on glossy objects, mostly on edges.
I’m not talking about technical issues. I’m talking about realism. It’s like shooting brightly lit people on greenscreen and composing them into a dark night scene. It’s just not fitting lighting information. Technically it’s still valid but it does not make any sense in respect to realism. It’s the same thing in Corona - you can do a lot of nonsense with moving objects, lights and what-not, but you’re starting to use simply wrong information as soon as you change something after caching your secondaries.
Gotcha…but i dont care abour realism in commercial projects anyway. I just wanted to say that i had no flickering with moving sun.
Moving smaller light sources should be problem of course.
You can show the setting of all the values of this material in your scene? .. screenshot
HDRI in environment - Portal - number light (values) .. etc etc !!?
In this curved surface was applied Normal modifiers?
Of course I can. More of that: I’ll share this test scene.
All scene surfasec is real geometry without any normal modifiers. Simple CoronaSky in background. No portals. Just look in attach.
BTW
As I tested this flickering was only presented with blurry reflections materials on surfaces. With standart materials without reflections I hasn’t catched it. So my first try to reduce this flickering was to get “Refl glossiness threshold” as low as possible to archive acceptable render times. But this way was wrong. It reduces the flickering but increases rendertimes for clean image. FutureFlat_CoronaTEST.zip (513 KB)
You need to check the values of Level and glossiness both for reflection and for the refraction (1 to 0.89/0.98)
HD Chace
Position sensitivity 100 does not help anything!
Max Record 99999 - vanishes (default is ok or values between 300 and 2500 - always depends on the circumstances )
A touch of Ray Tracing 28/32
I took an example from your slot material “Corona Glass win”
the yellow arrow indicates that the material you produce more or less noise (from personal experience)
Unfortunately I can’t really understood what this settings do (Positional/directional sensivity). In online interactive help they described as is. But as I’ve tested Positional sensivity set to 100 resovled flickering in this case. May be some flickering was left, but I can’t see it in animation so I think it’s no matter.
Sorry, but I didn’t undersrtood what do You mean A touch of Ray Tracing 28/32 .
Glossiness from 1 to 0.89/0.98 is a good idea and I’ll try to check this in near future.
Position sensivity 100 is not Holy Grail of course, but it really helps me to produce flicker free render with lower rendertimes in this case.
Max Record 9999 is recommended setting by online documentation. Why and what this means - I don’t know
Final animation is rendering and after some post I’ll share it in gallery. I’ve chacked it in progress and it seems that the flickering is gone.
