Well, no. Manifold is not just denoised caustics.
Secondly the caustics generated by cycles CANT be sharp due to an infinite search for those rays.
Yes i am happy for Cycles X, it will be easier to test different approaches, but the problem of full light transport is still not (properly) solved, not even by Disney & Co. Even bidir VCM has issues.
To be honest, IMHO, I see only 2 REAL solutions for full spectral unbiased light transport:
- Either a hardware solution where a big player like Nvidia or AMD are implementing the full spectral MLT equation in hardware and we also really have speed, or (more unlikely)…
- There is a genius that can invent a kernel on GPU level that can operate MLT spectral with interactive framerates. For that we would need a TRUE GENIUS. This is no small feat, and maybe even impossible given the challenge at hand.
So, yes, Manifold Sampling Caustics are NOT the ideal solution for MC PT. But a really good approach. Ideally we would need something completely different in a renderer.
Maybe spectral MLT is not the best approach either… maybe there are other ideas that could achieve unbiased interactivity with caustics… who knows…
I want to add that ideally a renderer would need to CALCULATE the rays in such a manner that even simulates the bloom and streaks of a camera lens trough the rays themselves. You could then load different Lenses with their internal lens groups and get perfect natural glass effects that would look perfect without post.
Octane does that for ex by a post filter, but that is not how a camera and lens behave naturally. So there are still a LOT of features missing in an ideal renderer. It just happens that the actual “unbiased” renderers are “good enough” with a lot of tricks.
We are still VERY far from the ideal renderer. And to be honest, i would want to see a programmable RPU (Render Processing Unit) that implements full calculus. This still needs to be invented.