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Unreal Engine is changing the game.

A respected colleague and friend emailed me a couple of months ago with this advice:

“If you’re planning on investing in render hardware any time soon, I wouldn’t”.

Included in the email was this link https://www.youtube.com/watch?v=qC5KtatMcUw. This is the Unreal Engine 5 demo.

I watched and was astonished by how close a real time gaming engine was coming to generating photo-real renders.  I had fiddled around with Unreal Engine from time to time and had a little familiarity with it.  So I decided it was time to do a deep dive and find out what this was all about.  I needed to know if it was hype or something real that could help my production pipeline.

Photoreal renders take a long time

As a VFX lighting TD, I am always focused on the render time vs quality balance.  If render time were never an issue, it was certainly a game changer, not to mention a budget changer.  Maintaining a render farm is EXPENSIVE.  After a couple of weeks of watching unreal tutorials and experimentation, I came to the conclusion that Unreal represents an existential threat to traditional renderers.  But it’s not quite there yet.  Here’s how it happened.

How VFX Renderers Came to Be

When render engines were invented, the prime engineering problem was to create realistic images.  This was the driving design parameter.  Therefore engineers sacrificed much to attain photo-realistic images, carefully learning to understand the physics of light and materials.  They wrote algorithms that would simulate these physical realities.  Mostly what was sacrificed was time.  The more physical an effect needed to be, the more time it took to render. Area lights take longer to render than point lights, but are more physical.   GI takes longer to render than area lights, but is more physical.  So the end users were provided with a choice.  Speed or quality.  And this is the dance we have danced ever since.  In VFX, we seem to have become fairly complacent about render speed, simply expecting long renders and then building massive render farms to handle the increasingly massive render times.

What Makes Game Renderers so Fast?

But when games were invented, the prime engineering problem was to make them playable.  In other words, they had to render at a minimum frame rate.  This design parameter took precedence over everything including image quality, which is why the older the game, generally the lower or simpler the image quality.  It makes no sense to have amazing imagery if the game is so slow that it is unplayable.  Then, once speedy game renderers were established, engineers took on the task of finding clever ways to incrementally improve image quality without impacting render speed. The focus here was never on creating physically correct lighting or materials, but to create lighting and materials that appeared close enough to physically correct that you can’t tell the difference.  Although there remain some limitations such as volumes, real time volumetrics, scattered light, imperfect penumbras and probably a few I haven’t found yet, it is crystal clear that UE is currently suited for, at a minimum, photo-real environments at mid to background distance, while hero elements may still need to be rendered traditionally.  However expect this to change.  As UE closes the gap, it is reasonable to expect traditional renderers to become unnecessary.

Solving Limitations

Probably a key to Unreal Engine achieving these feats for vfx production would be for them to relax the frame rate requirement in cases where more complex lighting and materials are needed.  I’m sure this concept probably horrifies the engineers, however for us vfx lighters, if a frame, instead of taking an hour on a traditional render box takes one second as opposed to 1/60th of a second, we are honestly OK with that.  Playability isn’t a requirements in vfx or animation as it is in games.

I can only conclude with this advice.

“If you’re planning on investing in render hardware any time soon, I wouldn’t”.

Nicholas Boughen is a VFX industry veteran, an Emmy and Gemini nominated lighting artist and co-founder of CG Masters School of 3D Animation & VFX, the world’s only full immersion studio production training centre.

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