Compositing Math In Blender (Physically Based Shading & Rendering)

So it is a long story how I got here. Interestingly the Compositing Math should be the first thing documented next to the shader description itself. And I remember I had hard times in the past to find Mental Ray (oh f* it is a fossil now...I used to use that a lot), and Arnold rendering. It is the dark side the documentations: COMPOSITING CG renders.

Now I can't remember actually where I found the source to that (because it is hard to find), but I have the receipt.

But couple of words about what Compositing Math is. 

Essentially when the energy conservation applies to the physically based shading and rendering it means the components of the surface properties absorb and reflect (and transmit) (the BRDF and or BSDF) the amount of energy that hits the surface. To solve this formula, practically it means the components are calculated combined together during rendering, and it allows that to output separately and combine those together during the compositing. So we can check what kind of passes (render elements, components, AOVs, whatever we call it) we want to access during the composition 

BUT if we want to recreate the render output (commonly referred as beauty), we need a specific set of passes. 

How do we know which passes? 

And how we can combine those? 

The answer is the Compositing Math my friends, AND also it is based on the shading and rendering architecture. So Cycles’ render passes based on the Principled BSDF (OpenPBR, Disney, Standard Surface) shader looks like this in Compositing:

• Diffuse

• Diffuse = ( Diffuse Direct + Diffuse Indirect ) × Diffuse Color

• Glossy

• Glossy = ( Glossy Direct + Glossy Indirect ) × Glossy Color

• Transmission

• Transmission = ( Transmission Direct + Transmission Indirect ) × Transmission Color

• Subsurface

• Subsurface = ( Subsurface Direct + Subsurface Indirect ) × Subsurface Color

• Volume

• Volume = Volume Direct + Volume Indirect

• Emission / Background (Environment)

• Add Emission and Environment passes directly.
  
  

Then sum:

Combined = Diffuse + Glossy + Transmission + Subsurface + Volume + Emission + Environment

However...let me know what is Your experience, whether it is a pixel perfect match or not.

And just a bit of summertime CG (knowledge) Entertainment. I always refer to this presentation because Naty Hoffman has a nice CG Explainer Voice to hear :)

Open Software Days 2025 ASWF

The Academy Software Foundation (ASWF) is the driving force behind open-source software development for visual content creation, bringing together the VFX, animation, and post-production communities.

Blender is now also a member between those giants.

It is really great that the Open Software Days 2025 is online on YouTube. 

Keynote from David Morin

The full playlist

Also worth to mention that the standardization have its specification platform:

https://vfxplatform.com/

Also, free database for cameras:

https://vfxcamdb.com/

Summertime's Hot Topics In CG / VFX

Finally, I've got involved a project where there was a very smooth cooperation between the shooting crew and the VFX on set crew (myself). Yes, sometimes it happens.

It was a happy chrome-balling time.

And a couple of selfies was taken as well.

I'm planning to organize an on set VFX workshop in Budapest (travel, accommodation, sightseeing included). If you are interested, let me know on the comment section. 

Getting closer to august it is always an exciting (at least) to check what is going on in the science of computer graphics #SiggraphIsComming, #Siggraph2025

Siggraph 2025 (Vancouver)

And last but definitely not least BCON2025 aka Blender Conference 2025 is coming too.

It seems my presentation proposal is accepted.

I'm waiting for this like the second coming—can’t wait to find out exactly how it’s all going to unfold. Will there be complimentary cocktails, cocaine, and courtesans included too?

Let's investigate :)

 

Blender - AI-T - NVIDIA - 2025

I praised the lord that I could participate at the first time on the Blender conference. I was really amazed that creative community is so creative, innovative, open-minded (and unsustainable (free Coca Cola wtf?)...but it is a different topic).

If you ever wanted to understand color management, my advice is to give up :) and just follow the best practices what Jacob Holiday showed us, for eg. Really, really powerful presentation.

If somehow you are not fulfilled after this ↑, check this: the Bible (of Color Management) aka Cinematic Color. 

Also worth to mention MagnumVD. This youngster do stuff, and I mean it.

My presentation was a little bit different and it is only for online communities.

BLENDER CONFERENCE TIKKTOKK SUMMARY

But what about NVIDIA and AI-T (artificial intelligence/information technology). I think the misconception about AI is that these stuff is for Artist. Not really. Artist enjoys creating stuff. If you want to skip the process you rather want to be startup or real estate investor. But there is this mantra: "be more and more and more efficient" but those are rather technical topics than artistic.

To contradict myself being an artist means we have craft (aka technical) skills to use tools like paint and brushes for painting. We get skills of using Blender and so on. So these are also technical topics. Since we use software (at least computer artists) that written in programming language leveraging scientific knowledge and research it really essential to at least have a grasp about the technology and science behind the tools what we are using as an artist. As the great painters hundreds of years ago, they were the masters of utilizing the chemistry of the paints and the canvas fabric and so on.

So that's where can be a major shift, or will emerge a new generation of artist who mastering the AI trainings to train the best models to create images, visuals, videos, sound, substance what cannot be done before. 

I really feel there is an interesting position of NVIDIA in that process of advancing AI technologies. Because they belong with us. NVIDIA has significantly advanced computer graphics over the past decades, and they recognize the enormous business potential in this AI field (just look at their stock market performance). However, this rapid development also challenges the value and role of being an artist in today's world.

Francesco Siddi also touched this topic on BCON however it is not really a thing.

Here we go 2025 (not to forget the energy crisis crashes the climate...turn off your computer and give up crypto-mining)

The Blender Conference 2024

 I'm heading to Amsterdam next week to participate in:

Blender Conference 2024

It is the next level to be part of the community, to get know people in person. Also, not to forget the mission to extent the VFX capabilities of Blender, in connection with developing, producing my first live action feature film featuring a CG Polar Bear as the protagonist. It is made with Blender (2D painting of the briefcase in Krita).

Pipeline Movies

The pipeline is always with us. Even if we don't think about it, because it is different from studio to studio, it is exciting to see how they deal with it.

Old but gold (actually, Rhythm & Hues no longer exists, which is the most depressing story of all time in the industry).

Rhythm & Hues - A Framework for Global Visual Effects Production Pipelines - SIGGRAPH 2014 from Murali Anagani on Vimeo.

Since the ShotGun Software has been renamed to ShotGrid, which is a more PC name for a production tracking system :)

Tony Barbieri and Don Parker; The Shotgun Pipeline at PSYOP from Autodesk Media and Entertainment on Vimeo.

The best pipeline presentation(s) of all time (still ancient which is a bit of a sign that nowadays there are less intersting talk on that field).

Not soo long time ago there was a discussion hosted by Side Effects Software at Siggraph.

Or I'm just getting old and only have good memories from the far past—cinesite's presentation about generalizing pipeline and implementing fTrack.

Last but not least: if we are talking about the pipeline, it's unavoidable to talk about Katana. The exciting part is that people may think that Katana is a lighting & rendering tool. Actually, it is a pipeline tool because of the nature of rendering. If you want to render anything, you must create a complex system to flow the data from DCCs (digital content creation tools) to the render engine. That's where Katana comes in. So here is a brilliant presentation about Katana deployment.

Facial enchancement in Blender

 I've just run into this article in Blenderstation. Pretty awsome.