Mango3 wrote: Thu Aug 29, 2019 5:12 am
Some comments on this:
The beauty of path guiding is it allows to keep the simplicity of path tracer without running into issues like, for example, light leaks associated with photons, yet it is capable of rendering complex specular-diffuse-specular paths.
It is unbiased (no systematic errors introduced and consistent) means it converges to the correct solution and works with say moving light sources in animations without introducing artifacts. Path guiding just learns the radiative distribution in the scene and guides the paths to the important parts, thus making it less wasteful.
What Dade stated about render speed is true, cached GI solutions are generally faster and for the typical archviz-interior scenes hard to beat (speed wise). That's why V-Ray and Corona are so popular among archviz professionals.
Simple scenes don't benefit much from path guiding and for difficult lighting (except the sds paths) LuxCore user can use bidirectional path tracing.
All light transport methods have their pros/cons. Depends what type of scenes one wants to render which method works best.
For more animation/vfx focused renderer, like our appleseed, it is a very good addition to have.
Well you're comparing caching and guiding as if they're competing for which does a better job.
Afaik these features aren't mutually exclusive, corona does pathguiding and uses caching. Also both vray's lightcache and corona's uhd cache don't suffer from lightleaks and can be used without problems for animations. They are both valuable, especially if they can be used both at the same time.
Biggest issue is pathguiding not being able to run on gpus. So unless pathguiding can bring same priced cpu ahead of same priced gpu in same generation in terms of performance, it just might be worth to explore other ways for getting photongi better and faster for example...
On another hand, luxcore already can already do hybrid rendering where cpu does lighttracing independently for caustics. Maybe having pathguiding for the cpu lighttracing part could give us caustics+sds on cpu while gpu does pathtracing?
Sadly of course in luxcore I've noticed heavy problems with leaking and odd reflections in more complex interiors with photongi.
Very thin objects (thin walls and floorboards on ground or wall decorations) can show a lot of problems no matter the settings.
And reflections of distant objects also tend to show weird variable bright spots.
