Water Displacement issue

[larsgehrt]

Hey guys,

I have this issue when I use a displacement on a transparent material, like water. See attached.

It creates these black outlines around the mesh that i comes in contact with. The displace is at 8k tiling and that reduces it, but it does not go away.

Has anyone encountered this or know a fix?

Thanks
Lars

[paride4331]

Hi larsgehrt,
Could you share the scene with the issue reproduced?
3dsMax > File > archive
Regards
Paride

[Pavlov]

I get same issue all over the time, for many years.

It depends on two factors:

- the actual projection size of the texture you're using for displacement. Same texture projected as a 20mx20m or as 100m x 100m will produce different black offset borders. The larger the projection, the larger the black line.
- The pixel resolution of your texture. The higher the resolution, the smaller the black border.

Afaik there is no solution atm. You'll always end with a black line somehow. This is tremendously bad for water and sea in general.

I take the chance to repost, as i did several times, that Octane displacement needs a total rewrite.
The lack of flexibility of Octane displacement makes me think of abandoning Octane, despite my love for Octane and the insane amount of production i did on it.

Vertex displacement is de-facto not usable, on large objects such as terrains you can just forget it.
Voxel displacement, on the other hand, just accepts a simple "texture" as input, which makes it nearly useless in 80% of the situations.

We need to use *nodeflows* as displacement input, and not just a texture. As example, mixing more maps through Ambient Occlusion, incidence node or just a noise is impossible. Again, any procedural needs baking in order to be used as Displacement, which makes displacement tiling all over the time.
Even the Chaos node is nearly useless for PBR gound materials, since it need baking for displacmement. So you break texture with Chaos in order to avoid tiling, then you must bake the result - so it will tile again.

These tools - and how they interact - need a deep rethinking.
I could provide dozen of solid examples where Octane material system is just not up to corrent standards - not even 5yrs ago standards i would say.
There is stuff that we easily do in other engines here in office, and these are just not possible at all in Octane, forcing Octane users to dumb workarounds - or just worse results.

Please #devs - your attention on material system is crucial for high end productions.
I get the impression that there is more interest on next cool feature to implement instead of making the roots more solid.
Let me know if i can help - i b-tested dozen software in 30yrs and and i can really help, plus i love Octane and it would be a pleasure for me - but i need a dev's solid attention and not the explanation of how current displacement works, like it happened on my previous reports.

bye
Paolo

[HHbomb]

Hi, Pavlov.
Which software do you use for rendering ?

[larsgehrt]

Hey guys,

thanks for your input. I have to agree with Pavlov on this. I do alot of water sims and renderings, and I find myself moving away from displacement mapping and using bump maps, which is of lesser quality in the end product.

I really hope that this can be fixed

I have attached a scene and a fast render for you guys. In the render you can see the white rim around the stones, this is the problem.

Thanks
Lars

[paride4331]

Hi larsgehrt,
Personally, I wouldn't choose this workflow to achieve this image, but that's not the subject of the post. That being said, as you can see, Octane Render's displacement nodes work well when used properly. I'm attaching the file so you can take a look and compare it with yours, in order to learn some useful tricks as well as the Kernel settings (Perhaps the use of the ray epsilon function was overlooked). I also add that it is not feasible to achieve a decent displacement using a low-resolution 8-bit JPG image. Additionally, when using a grayscale image (at least 16-bit depth and of adequate resolution), it would be correct to use the grayscale node instead of RGB. However, one thing should be mentioned: the interpenetration of the 'water' plane and the stones should be avoided. I didn't perform any boolean operations, precisely to demonstrate that the displacement works well anyway. I hope it's helpful.
Regards
Paride

[larsgehrt]

Thanks man, appreciate your time on this.

The scene that i made for you is just to highlight the obvious, so thats not how i do the scene normally.

Here are some shots where I camouflaged the borders with white foam, but some places you can see a black trim on the stones in the water.

https://youtu.be/FZFFHh8qLtc?si=qDi2c-jPNQz8b7n4

Thanks!

[paride4331]

Hi larsgehrt,
Did you use texture displacement or vertex displacement node?
Regards
Paride

[larsgehrt]

For the video i used texture displacement.

[paride4331]

Hi larsgehrt,
try to take a look at my water material.
In any case if you have too many sharp edges, try increasing the texture detail of the geometry you're using, like water, or increasing the subdivision level of the vertex displacement.
Regards
Paride