for me this is what iam looking for

It might be a bug, better be a bug that means when fixed all this render time will be a lot faster..

Well, it is a little different bug not related to NVIDIA drivers. When they apply a fix, Iray would render with *normal* speed those scene featuring props with displacement a glow maps textures:
https://forum.reallusion.com/424475/Glow---Displacement-maps-delay-Iray-renders-exponentially

It might be a bug, better be a bug;) that means when fixed all this render time will be a lot faster.. I think that's what the new NVidia driver was about - faster rendering especially with RTX cards but again, there is a bug because it currently doesn't work with Reallusion software.

Store Page Link 
76% of original size (was 665x19) - Click to enlarge
AMD 4.5 GHz 16 Cores  | 128 GB | RTX 4090 | Window11 | Houdini FX 18.5 | Zbrush 2023 | Maya 2014 | Adobe CS6 | Sonar Producer X3 | iC8, CC4 | DTS Master Audio Suite | Perception Neuron 32 Alum Edition | Akeytsu 

I'd have to say that IRAY simply needs to do more calculations with displacement, it takes a long time with photo real mode. it really depends on what part of Iray you want to use because if you enable everything it will be slower..

Yes, displacement would put some constrain on render, but not to such a scale. It is a bug. Pls. see my update to the original thread.

76% of original size (was 665x19) - Click to enlargeI'd have to say that IRAY simply needs to do more calculations with displacement, it takes a long time with photo real mode. it really depends on what part of Iray you want to use because if you enable everything it will be slower.. also having iClone with high render mode while iray tries to  do it's own thing  will slow it all down . I'm using an RTX 2080Ti and it can take a day for say 300 frames..  (also had other things open) I did have a second card but the latest nvidia driver messed up CC3 and iclone  from being able to load. I  have a different approach to foam that I'dd be trying later, probably when I make surf waves.



Store Page Link 
76% of original size (was 665x19) - Click to enlarge
AMD 4.5 GHz 16 Cores  | 128 GB | RTX 4090 | Window11 | Houdini FX 18.5 | Zbrush 2023 | Maya 2014 | Adobe CS6 | Sonar Producer X3 | iC8, CC4 | DTS Master Audio Suite | Perception Neuron 32 Alum Edition | Akeytsu 

@Ascensi Time is of an essence in most production environments. And soft cloth physics is one of the most time consuming feature to deal with.
As you said not many people are willing to get under the hood for broken belt replacement. So I am sure you are going to sell lots of copies. ;)

In other news :) ... As I dug deeper into this I found out that Iray does not really like displacement maps.
While iClone has no problem dealing with displacements, Iray would suffer greatly.
(Suppose there was a reason they put "Preview Tessellations and Displacements" check box there).

OK, so I went a little overboard with this. 80K tris for a foam plane and tiled displacement map for it.

The Iray initialization went from a few seconds to whooping 10 minutes... Wonder why??

76% of original size (was 665x19) - Click to enlarge

Only after displacement map removal I got normal initialization and render times

76% of original size (was 665x19) - Click to enlarge

I could probably draw the same with regular base color texture. But still wonder if it is NVIDIA, or iClone implementation deficiency.

UPDATE: The "Light hierarchy..." message gave me a clue... It is problem with lights.. not displacement. Or rather combination
I also have a Glow map for the foam plane. If I take glow map out and leave displacement in place I also get normal initialization times.

Glow map is considered a light source. And it looks like displacement map multiplies light sources for the mesh which otherwise should be just 1 (one).
And this is where 10 minutes delay is coming from. Definitely a bug and I would report it after more tests....

It is a bit disheartening, as I spent days on getting everything correct Iray Material and then figuring all the particulars but in the end i know it's a cloth based effect and anyone could have done the same in the last couple years or might even examine all the details and tell others. So as I try to find the means to support myself I wonder if the time spent on figuring this stuff out for others is worth it. But the product still makes good for those that wouldn't know how to set things up and it comes with everything to save people the time and frustration to figure these things out for themselves.  Overall I see that it's good that you're showing people that I'm not selling snake oil :)
as some might of wondered. I've tuned everything in my project, but your off to a good start.  I was wondering for a bit why you didn't use the included realistic Iray Material from my package ;)

Store Page Link 
76% of original size (was 665x19) - Click to enlarge
AMD 4.5 GHz 16 Cores  | 128 GB | RTX 4090 | Window11 | Houdini FX 18.5 | Zbrush 2023 | Maya 2014 | Adobe CS6 | Sonar Producer X3 | iC8, CC4 | DTS Master Audio Suite | Perception Neuron 32 Alum Edition | Akeytsu 

Thank for the update folks. As I said, very cool idea with whole lot of potentials.
Hope you don't mind me revealing your secrets :)

Just a heads up, I managed to get a boat working with the waves @toystorylab   I will be updating the package soon with an example. 



After that i'll be working on stormy waves and the surfing type. Rivers will be another thing to try.

Store Page Link 
76% of original size (was 665x19) - Click to enlarge
AMD 4.5 GHz 16 Cores  | 128 GB | RTX 4090 | Window11 | Houdini FX 18.5 | Zbrush 2023 | Maya 2014 | Adobe CS6 | Sonar Producer X3 | iC8, CC4 | DTS Master Audio Suite | Perception Neuron 32 Alum Edition | Akeytsu 

Thanx for revealing findings :D

As I spend quite a lot on assets, I decided to simply buy it and give it a try.
And the credits definitely belong to Ascensi for having this brilliant idea...

Here is my first result:



That's good enough for me to get some ocean in my movies...



Toystorylab on Vimeo : 76% of original size (was 665x19) - Click to enlarge    Crassitudes (my "Alter Ego") on Youtube: 76% of original size (was 665x19) - Click to enlarge