UHD Cache question

[tolgahan]

I have some questions about uhd cache.

Imagine turning 360 degrees around a square building. At which frame shall i save uhd cache? In the front of the building, at the back or on the side of the building?

Is it logical to make precision 20 as we will wait only for one uhd cache? What can we do for less flickers?

For instance at which number would we have a better result for gi vs aa balance animation?

I want to make waves with animated noise on the water. Would it work to pre-save uhd cache or should i use still frame computed?

No denoiser
65 pass per frame
1080p

Full hd 1080 p
420 frame
Every frame 60 pass and full denoising

https://forum.corona-renderer.com/index.php/topic,12539.0/all.html

[cecofuli]

Too fast, and you need a little bit of Mblur and DOF.
You can do it with Velocity pass and ZDepth (no need to redo the entire animation)

[TomG]

Some thoughts on the first question - you can test what is in the UHD cache by generating and saving it, then turning off light sources, swap to load from file, and render, to see the lighting from the UHD Cache only. You may find that all your surfaces have illumination.

Been doing some tests to see (and someone will correct me if I am wrong!). What is visible at rendering does make a difference to what UHD Cache info is stored, e.g. if an object was completely out of frame, it had no UHD Cache info saved. So what seemed to work was:

- Generate from scratch and save the UHD Cache at the first frame
- Change mode to "Try to load and append" and leave it set to save the UHD Cache
- Render other frames which will load the previous cache calculations and add in anything new that it now sees from this frame. You could do this manually to select key points in the timeline, or you could automate by setting render time to 1s and rendering the animation set to every nth frame (smaller n I would expect to yield more accurate results)
- Switch to Load from file when all done.
- You can always try turning off all lights again at the end, to check what is in the UHD Cache as a result of this process

Only just experimented with this, so if anyone can add more info, please do!

Hope this helps!

[TomG]

On the animated noise question, I feel that saving the UHD will work fine - I believe it all depends on how much that noise is affecting light bounces, which is probably not much / not at all. You could try the "turn off all lights and render just using the loaded UHD Cache" to see if the noise in the water is causing visible results in the cache. Again, comments welcome if I am astray in my thinking!

[maru]

Sorry for being a bit late here. Generally what Tom says seems to be correct. Some notes:

Imagine turning 360 degrees around a square building. At which frame shall i save uhd cache? In the front of the building, at the back or on the side of the building?

As Tom said - you can use the "load+append" option to add new records to the UHD Cache for multiple frames. BUT usually UHD does not speed up rendering som much in outdoor scenes, unless some heavy light bouncing is visible.

Is it logical to make precision 20 as we will wait only for one uhd cache? What can we do for less flickers?

I would say that setting precision to 20 is never logical (it will not make much difference, and the rendering will be probably a bit slower).
When you are using "animation" UHD preset, or loading a saved precomputation, then there should be no flickering at all.

For instance at which number would we have a better result for gi vs aa balance animation?

Sadly there is no universal answer here. It depends on the scene type. Same as with static images:
- lower GIvsAA = better antialiasing, worse GI
- higher GIvsAA = better GI, worse antialiasing
But in most cases adaptivity should do its magic here, so I would leave everything at defaults.  :)

I want to make waves with animated noise on the water. Would it work to pre-save uhd cache or should i use still frame computed?

I would try with pre-saved UHD. Even if there are some differences between what is saved in the UHD and what is currently in the scene, then path tracing will eventually solve it.

[tolgahan]

Thanks maru I will try