Arnold DoF / Motion blur passes with Davinci Resolve/Fusion

[thor98_]

Hey,

For the project I'm working on I need to add depth of field and motion blur. I've thought of rendering out passes and adding it in post through Davinci Resolve, but I really struggle to understand the render passes/compositing workflow.

Do you export all passes in 1 EXR file or separate? How do you easily composite them with DavinciResolve/Fusion?

If you have a model and camera animated in all 3 axis, will the motion blur look correct?

If you don't want everything in the scene to have motion blur, what is the easiest workflow?

[CiroCardoso3v · Accepted solution]

Are you working on a still image or an animation? Depending on your disk, having separate files for each AOV is a better solution.

Do you know how to rebuild a Beauty render? I can share with you a Fusion Template that will help you with that.

Install Reactor for Fusion. This will give you access to a database of free tools. Including tools for Zdepth and Motion Blur.

For Zdepth there is one called DepthDefocus and for Motion Blur the Vector Motion blur.

[thor98_]

Thanks for your reply!

I'm working on an animation - 120sec / 24fps / 1920x1080.

Not sure how to rebuild a beauty render - would be cool to have a look at the template! I'll have a look at Reactor some time later, that sounds pretty cool!

[CiroCardoso3v]

You don't have to rebuild the Beauty, that is just in case you want to do some extra tweaking. But in case you are interested, here is part of the template.

And to help you to change the paths for the loaders - https://forum.blackmagicdesign.com/viewtopic.php?f=22&t=57396

[thor98_]

Ah, one more question - do I need to fiddle around with any motion blur settings when rendering out AOV's? Or is it enough with just ticking the 'motion blur' in camera setting and 'Instantaneous Shutter for Motion Vectors' in render settings?

I've read about transformation/deformation keys but I have no clue if I need to mind them.

[thor98_]

Oh silly me - one more question - should I export beauty pass in EXR or is PNG OK?

[CiroCardoso3v]

You should need to change anything. The motion blur is done in Fusion and doesn't need to be calculated. This link provides more info regarding the pros and cons

https://docs.arnoldrenderer.com/display/A5AF3DSUG/Motion+Vector+AOV

[CiroCardoso3v]

Always EXR. In particular for data AOVs, like Z, N, Motion.

[thor98_]

Thanks for everything!

I've been reading further on various sites and here's the workflow I'm thinking of going with:

- Rendering out AOV's for rebuilding the beauty (I really like having control over various passes in post)

- Buying Frischluft lenscare for Fusion that comes with Davinci resolve

- If possible find a plugin that splits up EXR file into each render passes and composites them so there's less blending to do, but I guess that's easy enough to learn in worst case scenario...

- Using denoiser, as any 'artifacts' brought with denoising will probably compliment the youtube compression...

It's the first time I'm doing anything to do with AOVs, denoising and z depth/motion vectors so I've been quite scared!

Oh that reminds me - how do I combine and save out all render passes and final frame in 1 EXR file?

At the moment, it renders out the final frame and the render passes to a separate file.

[CiroCardoso3v]

No problem at all

Rendering out AOV's for rebuilding the beauty (I really like having control over various passes in post)

Is a quite powerful way of working. Makes everything way easier and avoids adjustments that would ruined your image.

Buying Frischluft lenscare for Fusion that comes with Davinci resolve

I would have a look first at the DepthDefocus first and see if you are happy with the results.

If possible find a plugin that splits up EXR file into each render passes and composites them so there's less blending to do, but I guess that's easy enough to learn in worst case scenario...

I am attaching the AOV settings that I use for my work. 

Using denoiser, as any 'artifacts' brought with denoising will probably compliment the youtube compression...

Have a proper look at the Noice settings. My advice is for you to use the Noice Imager, play with the values and then use it. Btw, if you are rendering an animation, don't forget the Lock Sampling option on the Arnold Renderer Tab.

It's the first time I'm doing anything to do with AOVs, denoising and z depth/motion vectors so I've been quite scared!

If you have any issues let me know.

Oh that reminds me - how do I combine and save out all render passes and final frame in 1 EXR file?

So you are rendering everything into 1 single EXR file?

[thor98_]

Thanks!!

I went ahead and composited the zdepth aov with DepthDefocus and it didn't look too bad with a few cubes. I'll try with my actual scene and see how it looks with that setup.

Thanks for the tip on Noice Imager!

At the moment I render 3 files - beauty, motion vector and zdepth. I'm curious if I can somehow combine them into 1 file when rendering them out.

[CiroCardoso3v]

Yes, you can

But I don't recommend you to do that. The file will become too big and will slow you down. If you are tweaking the Beauty, you don't need to load the motionvector and Z every single time. Also, you may want to use Cryptomatte.

[thor98_]

Wow. Cryptomatte looks very useful just like having separate render passes. I'm going to give all the AOVs a look and see if there's anything else I could implement in my workflow!

I wonder. If I select an object with cryptomatte and change its brightness, and there's a volume light in front of the object, does the volume light also change in brightness? I would assume it, does as it seems cryptomatte is mostly just for selecting things.

Thanks again for recommending I check out default defocus, on my high detail scene it actually looks great. Only if I zoom in I start to notice some edge issues.

There's one thing in Davinci Resolve/Fusion that I'm growing gray hair from ... at random it uses 90% CPU and jumps up to 20gb ram usage.

Another thing is, in Fusion tab, I set LUT to gamma 2.2. But when I view any other tab e.g Color or Edit tab, it goes way darker than it's supposed to.... I wonder what I need to change here. It's frustrating that it doesn't apply the Gamma setting that I set in the Fusion tab.

[thor98_]

I took an 11 hour nap after I wrote that message lol, that was getting way too frustrating than it had to be.

I'm going to continue searching for an answer as to why LUTs changes depending on which window I view

[thor98_]

this is frustrating it wont change to gamma 2.2 no matter what i do

[thor98_]

this is the most frustrating video editor ive ever worked with

my 3ds max render is exported at gamma 2,2

davinci resolve is EXTREMELY DARK and gives me no way to set gamma

if i go to fusion tab and set lut to FUSION VIEW LUT and change gamma to 2,2 it displays correctly but ONLY in the fusion tab

[thor98_]

I've attached some screenshots showing the issue ......

How it's supposed to look (viewing fusion tab)

How it's NOT supposed to look (viewing any other tab)

[thor98_]

Lots of frustration + no edit button makes for a very confusing thread....

Apologies about that. I was knocking my head against the table.....

This video at 1:50 fixed it for me. Who would think it would be that easy.

https://www.youtube.com/watch?v=T2dFnXFiCZE

[CiroCardoso3v]

No worries. I think is more now Fusion and DaVinci help. A good place is this Discord server

https://discord.gg/MbRYPpgu

[thor98_]

Yep I've joined their Community server. Nice people there too.

My renders are looking great with the default blur. It also blurs out some of the existing image noise so I'll be able to cut down even further on render times. I'm so glad you helped me with compositing as otherwise my project would take 1-2 months to render out. :turtle:

Really happy to finally have the EXR issue out of the way .... that was not fun.