Multi-channel EXR or Single channel EXR in Nuke? (Twitch Tip of the Day)

DwarfMarine asks on Twitch: 'What's better? A Multi-channel EXR or a Single channel EXR?' This Tip of the day was recorded live on Twitch on the 22nd of March 2020. Have a question? Join my streams every week and maybe your question will become a video on Hugo's Desk. / hugosdesk
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#compositing #nuke #vfx

[@NoahCatan]

Thanks for answering my question on stream and taking the time to make it available on KZbin! Very useful information, I'm definitely sending this to all my comp friends :D

[@HugosDesk]

No problem, thanks so much for watching.

[@PLOFstudio]

Nice point there!! just wanted to add something. Network measurement are Megabites while the measures we are using in computers locally are megabytes, which is 8 times more than megabites, that means, a network working at 100 mbps means it can handle 12.5 megabytes per second, so, if you open that 40 mb file on a 100 mbps network, you are actually taking 2,5 seconds to open just that file. Said so, actually most networks are at least 1000 mbps, which are 125 megabytes per second. So your point is even more clear now. Imagine if we are now talking about a 500 mb exr, now you can kill yourself if you are on a slow network, hahaha

[@yacinejulian6678]

So cool, very clear now

[@keysignphenomenon]

thanks

[@bisounours111]

independently of the speed, il EXR multi, we can have .... Cryptomatte ..... And this is very cool.

[@HugosDesk]

This project is 4 years old so at the time I did not have cryptommattes. Thanks for watching

[@VladAndreiLazar]

A few comments: Why not multipart ? All the advantages of multi files and nicer to organize.

[@HugosDesk]

Because it's easier to load and playback individual EXRs than a heavy multi-pass EXR. Also more tricky to share remotely with your team.

[@VladAndreiLazar]

the questions is how do you store those multiple-passes. In the olden times you had only multi-channel. Since a few years now you also have multi-part. With multipart, only the relevant data is read: If you never access a pass, it never gets read or decompressed. Nuke prefers, obviously multi-part.@@HugosDesk

[@Aldeavfx]

Hey Hugo! Whats your RAID setup? External? RAID5? thanks!

[@HugosDesk]

I’m using a Raid 5 with a LaCie 12big with 48TB and a internal Raid 0 with 8x mv2 blades. The large storage is for footage and it runs at around 1.2K MB/sec and the internal is for caching and it runs at 16K MB/sec

[@Aldeavfx]

@@HugosDesk Amazing, thank you!

[@jellsart]

Thank you for sharing :) !

[@HugosDesk]

No problem, be safe

[@TriniFlix]

Thank you !!

[@HugosDesk]

You're welcome!

[@realkumarakesh]

Why do we need multi pass?

[@jtsanborn1324]

Do you use flame? if so, what do you use it for?

[@HugosDesk]

I don’t use Flame but Flame is a compositing application from Autodesk. It’s mostly used in commercials because it is very fast.

[@Ansari_Arshad]

Great Explanation Sir, Every thing is clear, 1 question regarding system config, i am Using : Core i9-9920x, 64Gb Ram, 2TB M.2 SSD, 2080Ti graphic card, is that config good for compositing ???, or is it good for teaching Purpose ??? Please Reply sir, Thanks for the Video.

[@awazsobare3827]

very good explanation . Question , you showed us previously how to create one single EXR with all the passes so that you call them when ever you need them , My question is , do you do that for all the shots and all the time ? because sometime the shoot is short or you will do small tweaks and you probably won't need Nuke channel system .

[@HugosDesk]

Yes I always do the channels stream regardless if it is a short or simple shot because I want total control but it’s up to you and your pipeline. Btw using EXR 2.0 would allow much better performance on playback. With 2.0 Nuke only caches the visible layer, so it does not read all passes at all times like 1.0