What If Luxcore RT

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Sharlybg
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What If Luxcore RT

Post by Sharlybg » Tue May 19, 2020 5:19 pm

As most of you know , the entire Graphic industry is moving really fast in the realtime direction. this is becoming more more obvious as we move foward in time.

1__ blender got eevee
2__ Nvidia release RT core / RTX
3__ D5 render and enscape render came with very plausible render quality
4__ Unreal engine 5 unveil Lumen (No more light cache needed)

My ponit is that we are not sure to be supported by EEVEE at some point. And even if it possible you have to re adapt 40% of your work to make it with eevee even from cycles. having our own Realtime engine can make a big deal. In that case i look toward a tech called Voxel cone path tracing. And who know if it is possible to just adapt current path tracer to Voxel cone.

Voxel render in Action : https://youtu.be/YO-FMJJA37o + https://youtu.be/EHaSzQTjlik

Voxel explain by Nvidia : https://youtu.be/EJTc_t3G-js?t=982

AND this thing can be probably boosted by RTX on AMD RT tech.

https://youtu.be/EHaSzQTjlik

EDIT a demo from Cry engine 2015 : https://youtu.be/y_VpsCHr970
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Re: What If Luxcore RT

Post by Sharlybg » Tue May 19, 2020 5:53 pm

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Re: What If Luxcore RT

Post by jc4d » Wed Jun 03, 2020 8:33 am

This would be great.

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Re: What If Luxcore RT

Post by 14AUDDIN » Fri Jun 12, 2020 11:01 pm

Godot Engine 4.0 recently also got real time dynamic global illumination
Tweet Link explaining current limitation: https://twitter.com/reduzio/status/1271 ... 48160?s=20

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Re: What If Luxcore RT

Post by Sharlybg » Mon Oct 05, 2020 8:50 pm

Maybe a first step in that direction. Will be very interesting to have :

https://news.developer.nvidia.com/rende ... twit_en-us
Render Millions of Direct Lights in Real-Time With RTX Direct Illumination (RTXDI)
October 5, 2020
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Until today, artists had performance constraints that artificially limited lighting complexity; real-time renderers simply could not support more than a handful of dynamic lights. For years, NVIDIA sought methods to remove this barrier and enable real-time rendering of arbitrarily complex lighting. With NVIDIA’s Marbles at Night demo shown at the launch of the Ampere GeForce GPUs, we achieved that goal.
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Re: What If Luxcore RT

Post by lacilaci » Wed Oct 07, 2020 6:09 am

Sharlybg wrote:
Tue May 19, 2020 5:19 pm
As most of you know , the entire Graphic industry is moving really fast in the realtime direction. this is becoming more more obvious as we move foward in time.

1__ blender got eevee
2__ Nvidia release RT core / RTX
3__ D5 render and enscape render came with very plausible render quality
4__ Unreal engine 5 unveil Lumen (No more light cache needed)

My ponit is that we are not sure to be supported by EEVEE at some point. And even if it possible you have to re adapt 40% of your work to make it with eevee even from cycles. having our own Realtime engine can make a big deal. In that case i look toward a tech called Voxel cone path tracing. And who know if it is possible to just adapt current path tracer to Voxel cone.

Voxel render in Action : https://youtu.be/YO-FMJJA37o + https://youtu.be/EHaSzQTjlik

Voxel explain by Nvidia : https://youtu.be/EJTc_t3G-js?t=982

AND this thing can be probably boosted by RTX on AMD RT tech.

https://youtu.be/EHaSzQTjlik

EDIT a demo from Cry engine 2015 : https://youtu.be/y_VpsCHr970
I agree, I currently work with unreal every day and I love it... I also think that by the end of next year realtime or semi-realtime engines could be pretty much a standard

However what you are asking for here is a completely new render engine(possibly a hybrid of rasterizing and raytracing) from scratch. That's a huge problem.

Another layer to this problem is GI, yes there is rtxgi for direct x but all the results I've seen so far don't come close to offline rendering by far. So you would still be stuck to some form of light baking that is not realtime etc... I kinda got used to baking cause new unreal has a gpu baker that is super fast but it's a process on it's own and you only get proper gi on static objects (fine for archviz work)

The only promising solution here is Lumen in unreal but that's probably a monstrous solution that I worry won't exist outside unreal (raytracing voxelized representation of scene+signed distance fields of meshes+screen space tricks for tiny details) and we still haven't seen how this performs in a man made environment like an archviz. So even this might turn out disappointing.

So not only a realtime luxcore would have to be a completely new render engine but Dade would have to skip decades of research made by these giant game company and on top of all that rely a LOT on nvidias toos and hw and DirectX.... That said, I'd still love to see that :D

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Re: What If Luxcore RT

Post by Sharlybg » Wed Oct 07, 2020 8:49 am

You are totally right Laci. And if you ask me where to put dev effort i will say more Speed ( with something like a GPU online learning path guiding solution) and better viewport performance.
As you say realtime is becoming standard as well as high resolution (2k / 4k) and this require a lot more computing power. Reason why i believe even with current Luxcore performance we still ne drasticall performance increase.
My last animation was for example 1mn per frame for arround a total of 960 frames and total rendertime turn arround 16 hours ( This was single image rendertime in the past) it is a single object animation.
I'm preparing a much bigger longer animation where i would like to have as much speed as possible :mrgreen:
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Re: What If Luxcore RT

Post by lacilaci » Thu Oct 08, 2020 5:54 am

Sharlybg wrote:
Wed Oct 07, 2020 8:49 am
You are totally right Laci. And if you ask me where to put dev effort i will say more Speed ( with something like a GPU online learning path guiding solution) and better viewport performance.
As you say realtime is becoming standard as well as high resolution (2k / 4k) and this require a lot more computing power. Reason why i believe even with current Luxcore performance we still ne drasticall performance increase.
My last animation was for example 1mn per frame for arround a total of 960 frames and total rendertime turn arround 16 hours ( This was single image rendertime in the past) it is a single object animation.
I'm preparing a much bigger longer animation where i would like to have as much speed as possible :mrgreen:
Well I doubt that pathguiding would provide substantial enough speedup. If UE5 lumen will work as good as it's current gpu lightmass solution then all offline renderers are competing with 60+fps rendering :lol: good luck with pathguiding there, this calls for a completely new and near instant solution to be able to compete.

Not even mentioning that currently the gpu lightmass baker can do GI in an interior in matter of minutes and then once it's baked I have high fps renderer that I can do thousands of frames of animation in a single gpu in a single day. Of course, it is not a renderer but a whole game engine so it's not easy to use and has it's own problems but also a lot of benefits, like it is a matter of minutes to turn the visualization in a standalone walkthrough app.

It is a question of time when more hybrid renderers will start popping out taking over. You can already find renders from unreal that match corona or fstorm at fraction of the time, shows like mandalorian use a whole realtime background sets, etc... We went really quickly from having fast rendering on powerfull machines to realtime acceptable renders on consumer hw and now with rtx 30xx and UE5 around the corner...

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Re: What If Luxcore RT

Post by Sharlybg » Thu Oct 08, 2020 8:05 am

Well I doubt that pathguiding would provide substantial enough speedup. If UE5 lumen will work as good as it's current gpu lightmass solution then all offline renderers are competing with 60+fps rendering :lol: good luck with pathguiding there, this calls for a completely new and near instant solution to be able to compete.

Not even mentioning that currently the gpu lightmass baker can do GI in an interior in matter of minutes and then once it's baked I have high fps renderer that I can do thousands of frames of animation in a single gpu in a single day. Of course, it is not a renderer but a whole game engine so it's not easy to use and has it's own problems but also a lot of benefits, like it is a matter of minutes to turn the visualization in a standalone walkthrough app.

It is a question of time when more hybrid renderers will start popping out taking over. You can already find renders from unreal that match corona or fstorm at fraction of the time, shows like mandalorian use a whole realtime background sets, etc... We went really quickly from having fast rendering on powerfull machines to realtime acceptable renders on consumer hw and now with rtx 30xx and UE5 around the corner...
I'm myself an Unreal Engine user since 3 Years Now ( Maybe people don't know because i don't talk about it :mrgreen: ).
As i answered on Blenderartist yesterday CGI tool vs Artists need is always a trade off. How much effort is require
By a given tool to reach a certain quality this is the question :

The unreal engine example :

Unreal engine work with a baking light system called Lightmass and this tech have a huge imapct on how artist work with the engine.

For each assets in your scene you need a 2 different UVmap. one for your material and texture layout and a secondmore importante for the Lightmass Light baking Data.I remenber staying on my computer for entier days jsut for this time consuming process.

Then you have the lighting workflow for thoses who want try to match offline renderer ( Even if Top quality Unreal can't match top quality Corona ).
You have to go throught a dozens off tricks and option with skillfully placed light in your scene to fake High quality GI.
I remenber That we also sometime have to override Unreal internal limation at the cost of huge lightmass compiling time. :roll:

And now there is RTX thing Plus upcoming Lumen Tech. My answer to that is the following :

There is no free lunch in computer graphic tech and anything speeding up a realtime renderer could probablly be adapted to offline rendering tech and vis versa.Baked light data are part of offline renderer since a while now.
To me Lumen is just a kind of Voxel cone tracing nothing new or extremelly hard to implement :
You can see some video of that here :

https://youtu.be/JjRELYlBVfg

And here :

https://youtu.be/YO-FMJJA37o

There is also a more convincing method called Radiance Probes Global Illumination you can see at work here :

https://youtu.be/mECv52eSjBo?t=125

None off those technique are far from offline renderer path tracing field ( they are mostly a rework of light equation aiming for speed vs precision aka realism).

ALL that said the whole industry is leaving rasterisaton for ray tracing and this not ony beneficial to realtime renderer it is also for offline renderer. The two world are being merged progressivelly that is all.
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Re: What If Luxcore RT

Post by lacilaci » Thu Oct 08, 2020 9:54 am

For each assets in your scene you need a 2 different UVmap. one for your material and texture layout and a secondmore importante for the Lightmass Light baking Data.I remenber staying on my computer for entier days jsut for this time consuming process.

Then you have the lighting workflow for thoses who want try to match offline renderer ( Even if Top quality Unreal can't match top quality Corona ).
You have to go throught a dozens off tricks and option with skillfully placed light in your scene to fake High quality GI.
I remenber That we also sometime have to override Unreal internal limation at the cost of huge lightmass compiling time. :roll:
This is quite an outdated information right there
lightmaps can be auto generated on import
the custom lightmass settings were popular for cpu lightmass which is completely different tool in both quality and speed compared to the new gpu lightmass which is better and much faster and currently in 4.26 beta also has denoiser options.

There are some problems with this solution, and you still need to be careful about some things, I'm not a big fan of lightmass, but it allows some crazy quality lighting super fast if you know what you are doing:

here's an 10 second baking VLM grid example on trees, something incredibly difficult and slow in old cpu lightmass:
https://www.artstation.com/artwork/W2ZkG2

Also I disagree about quality:
https://www.behance.net/gallery/1056932 ... l%20engine

https://www.behance.net/gallery/1016424 ... l%20engine

https://www.behance.net/gallery/1055682 ... l%20engine

https://www.behance.net/gallery/9765458 ... l%20engine

I easily take this quality in realtime over waiting for a single render even minutes. And many clients will too.

Sure, there are still many cases where you would run into issues, and I'm not saying this is best solution right now... However I think in a year that might be a different story, not only for unreal but otoy working on brigade, blender eevee might get raytracing features and some gi solution. Realtime rendering will take over in a year, even if we look at eevee or brigade they are more like semi-realtime.
anything speeding up a realtime renderer could probablly be adapted to offline rendering tech and vis versa.Baked light data are part of offline renderer since a while now.
To me Lumen is just a kind of Voxel cone tracing nothing new or extremelly hard to implement
it is a bit more complex :lol: :

"Lumen uses ray tracing to solve indirect lighting, but not triangle ray tracing," explains Daniel Wright, technical director of graphics at Epic. "Lumen traces rays against a scene representation consisting of signed distance fields, voxels and height fields. As a result, it requires no special ray tracing hardware."

To achieve fully dynamic real-time GI, Lumen has a specific hierarchy. "Lumen uses a combination of different techniques to efficiently trace rays," continues Wright. "Screen-space traces handle tiny details, mesh signed distance field traces handle medium-scale light transfer and voxel traces handle large scale light transfer."

They use voxel tracing in a limited fashion and add other method to fully solve GI. But until they show off some mostly indirectly lit interior with multiple bounces I remain sceptical about this. Their demo shown mostly rocks which could hide imperfections and leaking in lighting...

I have some doubts this can get adapted to pathtracing easily, or if it's even possible, especially if you want it real time...
There is also a more convincing method called Radiance Probes Global Illumination you can see at work here :
This is what rtxgi or ddgi does, and not only it runs on directX and RT cores but it is also highly dependant on probe density and from the results I've seen it falls apart rapidly if smaller objects are indirectly lit in a larger room for example. At some point it might evolve into something more powerful but right now it's a bit complicated and also not sure how pathtracer would use probes and how it would impact quality.
ALL that said the whole industry is leaving rasterisaton for ray tracing and this not ony beneficial to realtime renderer it is also for offline renderer.
So far I'm seeing lot of hybrid solutions rather than leaving rasterization. Raytracing gives fast and high quality shadows, proper reflections and refractions, but for GI it is horribly slow.

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