car caustics reflective specular caustics study

[seandunderdale]

As to matching an *exact* look, by the pixel (f.e. to integrate with a plate that has other parts of the same caustics), i highly doubt that's doable by anyone at all, no matter the tech, currently.
Besides, of course, manually painting the caustics in.

Exactly, this is what I was getting at. You could do a version that looks as good and believable, but not the same placement of highlights. If you had a clean plate, you could create a version, I think, that looks just as believable to a client.

[sirio76]

I've done some test in the past and given the same conditions Vray caustics reproduce real caustics very well.
Here is an example inspired from this scientific test:

https://sciencing.com/happens-light-...m-8557530.html


Results are very close and I'm expecting that in general if geometry, shaders and lights are accurate you should be able to get accurate results in every scene.
The real issue is that to do that in a large scene, even if you tweak the photon map you will still need to use a massive number of photons, so huge render time and a huge RAM amount.

[madcat117]

madcat117 this is your final warning - stop spamming the forum. One more thread like this and we'll be forced to remove your posting rights.

And once again - if you really want to help - it will be very beneficial if you have an example of a renderer that meets your expectations.

Posting images and video examples that Vray cannot produce is not trolling at all in fact it only continues to highlight your arrogance that Vray is some kind of incredible render and its not because the boys over at Octane are light years ahead of your progressive caustics solver with their GPU photon tracer kernel but its okay to think your cool and special right because your product manager therefore you have this illusion in your head that you have some kind of authority over me which you don't as I will continue to make fake accounts as I please

[^Lele^]

Here is a file for you to play with, built from Cosmos assets (with some small modifications to shaders to make them work for caustics.).
I attached the RGB and the Caustics RE, containing all -and only- the caustics traced in the scene.
As linked, the Max file is set up to use the old photon mapping, as it's currently much quicker than the progressive one.
You can however switch to progressive and watch the caustics pattern emerge from pass 3 onwards.
On my old PC (AMD 1900X, 3.5Ghz locked freq.), the photon map takes around 3 and a half minutes to compute, and the rest of the rendering goes in a couple of minutes, so it remains a bit noisy still.
Progressive caustics would need a slightly different render settings setup, to minimise the speed loss due to the current state of the tech, but would produce sharper and more accurate caustics thanks to MLT guidance.

[sirio76]

Posting images and video examples that Vray cannot produce is not trolling at all in fact it only continues to highlight your arrogance that Vray is some kind of incredible render and its not because the boys over at Octane are light years ahead of your progressive caustics solver with their GPU photon tracer kernel but its okay to think your cool and special right because your product manager therefore you have this illusion in your head that you have some kind of authority over me which you don't as I will continue to make fake accounts as I please

One suggestion before you get banned from Chaos and Otoy forums, life is short, you should not waste your time like this.

[kosso_olli]

Thanks, so only the car is CGI?

Yes, only the car.

Also, those car caustics seem doable in CG to me. Anyone think those results are impossible to get? Might be fiddly but could get close I think.

We did this in the past with photon mapped caustics as well. Now with the progressive solver, it is much easier to get a good result.

While i personally understand the user's frustration and motive, i can't but agree on the fact that posting as he did (here, and on the octane forums, for size)

He has been active in the Corona forums in the past, too. Posting his studies for the progressive solver all over the place.

[kosso_olli]

Posting images and video examples that Vray cannot produce is not trolling at all in fact it only continues to highlight your arrogance that Vray is some kind of incredible render and its not because the boys over at Octane are light years ahead of your progressive caustics solver with their GPU photon tracer kernel but its okay to think your cool and special right because your product manager therefore you have this illusion in your head that you have some kind of authority over me which you don't as I will continue to make fake accounts as I please

Well, this is not true. Here are two images, from a real production job where we did exactly what you described in your first post in this thread. First image is the end result, second image show the caustics pass. And this was done with the older photon mapped approach. The same technique still works with progressive. Just because you do not know how to get such a result does not mean V-Ray (or any other engine supporting caustics) can not do it.

[fixeighted]

Oliver, I honestly wouldn't give this guy the time of day or any explanation of your workflow/results.
He's singularly managed to annoy quite a few people who have actually attempted to help him, as well as
probably the majority of the devs, so it's now clearly pointless to engage, as he appears to be on some sort of irrational crusade.
Funny to see initially, though ultimately rather sad.

[Mokiki]

At this point it looks really like he is just trolling or looking for attention. For every new "reference" he finds he creates a new thread instead of keeping things inside one where people already tried to engage or help.
Though I guess the one plus side of madcat's excessive posting were the neat images Oliver posted.
About the recent caustic pass Oliver posted where those caustic generated with the actual light setup of the scene or were specific lights placed that only contributed to the caustic generation? I assume the latter but am still curious.

[kosso_olli]

Oliver, I honestly wouldn't give this guy the time of day or any explanation of your workflow/results.
He's singularly managed to annoy quite a few people who have actually attempted to help him, as well as
probably the majority of the devs, so it's now clearly pointless to engage, as he appears to be on some sort of irrational crusade.
Funny to see initially, though ultimately rather sad.

Yeah, you're probably right. I just wanted to show that V-Ray can in fact do what he asked for.

About the recent caustic pass Oliver posted where those caustic generated with the actual light setup of the scene or were specific lights placed that only contributed to the caustic generation? I assume the latter but am still curious.

Hey Oliver, here's Oliver. The caustics were generated with a VraySun positioned roughly in the correct location, corresponding to the shadows etc. The sunlight was set to produce caustics only, no further lights in the scene.

[fixeighted]

Hehe yeah, I was fooled by him in another post regarding getting caustics from an indoor light through a glass.
I clearly showed him that it was perfectly achievable but it seems to have not made any difference, as he's I think more interested in
trying to prove some odd point that exists in his head only

At least it's given some new exposure to some of your cool auto stuff, so result!

[sirio76]

odd point that exists in his head only

This.
He did the same on the Octane, Corona, Sidefx, Blender, Unreal, Luxcore forums using multiple account, probably also on other forum, this since 2018(at least).
I don't think he is a troll, probably have some other "issues".

[Mokiki]

Yeah, you're probably right. I just wanted to show that V-Ray can in fact do what he asked for.



Hey Oliver, here's Oliver. The caustics were generated with a VraySun positioned roughly in the correct location, corresponding to the shadows etc. The sunlight was set to produce caustics only, no further lights in the scene.

Thank you Oliver for the small breakdown.
Best regards,
Oliver
:P

Joking aside that setup is still more low maintenance than I figured it would end up being. I always tend to want incorporate more caustic effects into my renders but then back off because in my head I am still stuck under the impression that caustics are just a hassle to set up. Will have to kick my butt next time and tell myself not to be lazy.

@fixeighted
Yeah that was one of the posts I was referring to.
It's completely fine to ask for help if you don't know something or are stuck.
But then following up by being insulting to the people offering support and pretending like a solution doesn't exist is just completely disrespectful.

[kosso_olli]

Joking aside that setup is still more low maintenance than I figured it would end up being. I always tend to want incorporate more caustic effects into my renders but then back off because in my head I am still stuck under the impression that caustics are just a hassle to set up. Will have to kick my butt next time and tell myself not to be lazy.

The setup is quite simple actually. The scene file Lele kindly shared is a good example of how it works.