Displacement issue (problem)

[tradstown]

Hello everyone!
This is my issues, maybe somebody explain to me something, maybe this is a bug and Corona team replaced 3D displacement by 2.5D too fast.

We have a plane 10km by 10km (32000px resolution). And Layered material with 2 displacement in materials. (actually, layered Mtl with displacement modes is a great thing, I like it so much, thank you for that!).
So when we are rendering near the terrain, we will se some details of the second material (with low height of displacement, it has 3m by 3m width, 8K resolution), but because of the pixel mode of the displacement in setup we can't get all details of the displacement. I tried to get more details with world size (units) but it didn't help, it even got worse.
Maybe I'm doing something wrong, but I think we can't get good results for big areas with displacement of Corona for now. I made some screenshots (look at the 8K render of mountains at 100% zoom pls (Displacement of big area 1.jpg)):

[tradstown]

[tradstown]

One more test. So how to get detalization far from camera like near on the ground?

Displacement - 1px (less number is giving me an error and do nothing)
The ware density of the ground plane - more then 50 millions poligons
The size of ground plane - 10km by 10km
And what to do with larger terrains in this case?

[tradstown]

Anybody?

[maru]

Hi, sorry for the lack of replies, I am not sure if I understand your issue correctly. Do you mean that the areas close to the camera are very detailed and the ones farther away have less detail in them? (are more "blurry"?)

If so, this is the expected behavior right now, because displacement in "screen size" mode is calculated depending on the image resolution. If many small details are smaller than a single pixel, they will not be visible, or at least not clearly.

I don't know what exact texture you are using for you displacement (e.g. is it a bitmap? or a procedural texture?) but you could try lowering the "blurring" value or cycling between different filtering modes. That might help.

Alternatively, maybe you could try using Scatter to get sharp, high quality details in the background? (e.g. scattering some rocks)

[tradstown]

Hi, sorry for the lack of replies, I am not sure if I understand your issue correctly. Do you mean that the areas close to the camera are very detailed and the ones farther away have less detail in them? (are more "blurry"?)

If so, this is the expected behavior right now, because displacement in "screen size" mode is calculated depending on the image resolution. If many small details are smaller than a single pixel, they will not be visible, or at least not clearly.

I don't know what exact texture you are using for you displacement (e.g. is it a bitmap? or a procedural texture?) but you could try lowering the "blurring" value or cycling between different filtering modes. That might help.

Alternatively, maybe you could try using Scatter to get sharp, high quality details in the background? (e.g. scattering some rocks)

Hello Maru! Thank you very much for reply!
I'm using RDTextures (8k resolution) on the second slot of displacement. I tried to change filters of bitmaps, the blur is 0.01 right now.
So my question, if we have huge area (in my case, this is 10km by 10 km), for example rocks that come out from the send, and we got it from some software (world creator, gaea, world machine), because if the 2.5D type and depending on pixel, we can't realized far away from camera details. I tried to use world size displacement and it can't give me 3ven this results, that you can see here.

Look at this guy please, his works was done not only with scattering, with displacement textures and we can see far details from camera:
 https://www.artstation.com/artwork/PeqJ9y

[maru]

Do you need you objects to be so huge? (10x10km) And do you need your render resolution to be so huge? (32k px)

I am asking, because this sounds like something extremely resource-heavy, requiring a lot of RAM.

If you are 100% sure that you need those numbers, and you would like to see very detailed displacement, even very far away, then maybe you could render your image as some kind of regions with even higher displacement quality? What I mean is setting displacement size to, let's say, 0.5px and rendering your image as a series of 1000x1000 squares.

[tradstown]

No, my image just 8K resolution as you can see attached file. 32K resolution - this is size of displacement texture for big ground 10km by 10km. As you can see works of that guy, he has a lot of details and views near the terrain and far from terrain as well. I just want to say, that displacement doesn't work in this case for a huge terrains in world size mode (not enough of memory, but I have 96 Gb of RAM) and in pixel size mode it works, but result is very blurred. I chose 8K resolution of image, because it has to draw more details of terrain in pixel model of displacement.
OR Maybe there is wrong tessellation when we use Layered mtl with few displacements in materials. Look at the new test please below (the stones, there is some artifacts because of tessellation, i think)
Maybe I should to upload the scene somewhere or my explanations is ok?

[romullus]

If you're using Corona 9, you could give a try to new CoronaPattern. The idea is to use large scale height texture for regular displacement and small scale height texture for the pattern. That way you could be sure that no single triangle will be sacrificed in the distance due to adaptivity. The downside of this method is that your large scale displacement should be real, i.e. highly subdivided plane with 3ds max native displace modifier on top.

[tradstown]

If you're using Corona 9, you could give a try to new CoronaPattern. The idea is to use large scale height texture for regular displacement and small scale height texture for the pattern. That way you could be sure that no single triangle will be sacrificed in the distance due to adaptivity. The downside of this method is that your large scale displacement should be real, i.e. highly subdivided plane with 3ds max native displace modifier on top.

Thank you! I'm using Corona 8 hotfix 2 because it is stable version for now. I'm trying to figure out how to render large scale displacement and don't lose the quality like that guy on Artstation with Cinema 4D and Octane. I'm pretty sure, it is something wrong with displacement possibilities in Corona. Look at the Real World units type of displace in properties of engine and what we can see at the render. This is the minimum number, that doesn't give me an error and using just 25 Gb of RAM. In other case an internal error.
I love Corona because it is so simple in setup, but I'm always feel some limitations in more complicated scenarios to get great results, so I just trying to figure out that and help found this limitations for Corona team, if you don't mind of course.

[tradstown]

And this is a whole ground of sand and rocks, that comes out from the sand. If we will have some animation for example from top view to the ground with details, stones and etc, it will become big problem for us =(

[romullus]

One thing you could do to check if it's really displacement that is giving you problems, or something else, is to duplicate your ground mesh, hide the original and cut small patches from the copy, on which you will do further tests. Those patches should be small enough to not cause excessive RAM usage even at smallest displacement subdivision, but large enough to be clearly visible at the distance. Make sure that one patch is close to the camera and one, or few of them are further away. Switch displacement to world size, set it at small enough value that gives you good details on the closest patch and then observe results on the farthest patch - if you see good details there, then it means indeed we have an issue with displacement handling, on the other hand, if you still can't see details that you are expecting to see, then it means that the problem is likely somewhere else (too small displacement details to be resolved in the distance, not enough resolution of final output, too strong filtering, etc.).

[tradstown]

One thing you could do to check if it's really displacement that is giving you problems, or something else, is to duplicate your ground mesh, hide the original and cut small patches from the copy, on which you will do further tests. Those patches should be small enough to not cause excessive RAM usage even at smallest displacement subdivision, but large enough to be clearly visible at the distance. Make sure that one patch is close to the camera and one, or few of them are further away. Switch displacement to world size, set it at small enough value that gives you good details on the closest patch and then observe results on the farthest patch - if you see good details there, then it means indeed we have an issue with displacement handling, on the other hand, if you still can't see details that you are expecting to see, then it means that the problem is likely somewhere else (too small displacement details to be resolved in the distance, not enough resolution of final output, too strong filtering, etc.).

Thank you for your activity very much! I'll try to do this today and upload here a result.

[tradstown]

One thing you could do to check if it's really displacement that is giving you problems, or something else, is to duplicate your ground mesh, hide the original and cut small patches from the copy, on which you will do further tests. Those patches should be small enough to not cause excessive RAM usage even at smallest displacement subdivision, but large enough to be clearly visible at the distance. Make sure that one patch is close to the camera and one, or few of them are further away. Switch displacement to world size, set it at small enough value that gives you good details on the closest patch and then observe results on the farthest patch - if you see good details there, then it means indeed we have an issue with displacement handling, on the other hand, if you still can't see details that you are expecting to see, then it means that the problem is likely somewhere else (too small displacement details to be resolved in the distance, not enough resolution of final output, too strong filtering, etc.).

Hello, Romullus! I made another try with world units of displacement (0.1m in the setup) and made the ground sizes smaller also, there is still no details as you can see. I'm using 32K resolution EXR file for Displacement. And that is result. World Size (unit) type of displacement - is dead. Or this result or an error and aborting of render. I hope it will be fixed in 9 version of Corona.

[romullus]

Hmm, that's not exactly what i meant. You scaled down the terrain from gargantuan to huge, but it's still too big for Corona displacement to handle in world size mode. Try to make something like in my attachment, where you'd have only few patches of terrain with displace, small enough to safely decrease displacement world size to centimeter, or even lower. You then judge from the closer patch if displacement is fine enough and then look at the farther patch to see if displacement is visible at all at that distance. The idea is to have terrain small enough, so to be sure that Corona does not run out of RAM and not produce artifacts because of it.

[tradstown]

Hmm, that's not exactly what i meant. You scaled down the terrain from gargantuan to huge, but it's still too big for Corona displacement to handle in world size mode. Try to make something like in my attachment, where you'd have only few patches of terrain with displace, small enough to safely decrease displacement world size to centimeter, or even lower. You then judge from the closer patch if displacement is fine enough and then look at the farther patch to see if displacement is visible at all at that distance. The idea is to have terrain small enough, so to be sure that Corona does not run out of RAM and not produce artifacts because of it.

Here we are. 0.05m in displacement World size mode. Less number in the setup getting me render of empty scene without displacement and object with this displacement at all.

[romullus]

So what do you think? Is displacement looks any better in the distance compared to your previous tests, or it's basically the same?

[tradstown]

So what do you think? Is displacement looks any better in the distance compared to your previous tests, or it's basically the same?

In the distance - yes, but near the camera - no =(

[romullus]

Ok, so now when we've establish that the issue is most likely because of displacement limitations and not of something else, we can try to see if it's possible somehow to overcome some of those limitations without waiting when the devs will improve the code significantly. For example, you could try to split your terrain in multiple separate meshes, based on their distance from the camera and add to each of them a Corona displacement modifier with increasingly higher subdivision quality settings. The idea is to try to force farthest away displacement not to degrade so much, so we can see more details and at the same time not to subdivide foreground displacement to the point where it becomes a performance issue.

[romullus]

Another idea - maybe you could use Chaos scatter to add some rocks and boulders in the background, so it could look more detailed. You could use Corona distance map in its density slot, so that the scattered rocks would gradually disappear closer to the camera as they would be replaced by the displacement.

[tradstown]

Ok, so now when we've establish that the issue is most likely because of displacement limitations and not of something else, we can try to see if it's possible somehow to overcome some of those limitations without waiting when the devs will improve the code significantly. For example, you could try to split your terrain in multiple separate meshes, based on their distance from the camera and add to each of them a Corona displacement modifier with increasingly higher subdivision quality settings. The idea is to try to force farthest away displacement not to degrade so much, so we can see more details and at the same time not to subdivide foreground displacement to the point where it becomes a performance issue.

I tried to do this, but, for more differences of the ground I used uvw randomizer for the second little displacement, so when I cut all area by pieces, on the render I saw seams because of randomization.
About Corona Scatter - yes, but it can help to add some details like stones, branches etc, but not the structure of the mountains. I hope You understand me. Look at the images please (Aaron's Westwood works). How to get same detalization of the mountains and not use the displacement?

[Basshunter]

Is this a known issue for the devs?

Would like to heard a word from them.

[romullus]

About Corona Scatter - yes, but it can help to add some details like stones, branches etc, but not the structure of the mountains. I hope You understand me. Look at the images please (Aaron's Westwood works). How to get same detalization of the mountains and not use the displacement?

I thought you are using two displacements, one large scale with little or no tiling for mountains and another small scale highly tilling for rocks and other details and the latter is the one that gives you the most trouble. Isn't that the case?

[tradstown]

About Corona Scatter - yes, but it can help to add some details like stones, branches etc, but not the structure of the mountains. I hope You understand me. Look at the images please (Aaron's Westwood works). How to get same detalization of the mountains and not use the displacement?

I thought you are using two displacements, one large scale with little or no tiling for mountains and another small scale highly tilling for rocks and other details and the latter is the one that gives you the most trouble. Isn't that the case?

You right, I'm using 2 displacements: One - the main structure of the mountains/rocks and another one is for little details (stones that comes out from the ground that we can see near the camera). There is no scatters at all in my tests.
I meant in general, that we can use scatter of course for adding some details, but for now the main test for me is using 2 displacements and details from them near and far from camera. Actually i miss about 3D Displacement.

[tradstown]

So, I found something maybe. I think the main thing of that great Aaron's Westwood works is vertex displacement or voxel displacement. It works in a different way from 2.5D displacement or 3D displacement, what I understood. Maybe I'm wrong, but Corona team, please, check Octane's render displacements. Maybe it will be useful for all of us. In any case, check all this topic for displacement bug, it is real of Real World Units in setup menu. And also check the tessellation when using few displacements in Layered Mtl.

[maru]

Could you share an example scene with us here? https://support.chaos.com/hc/en-us/requests/new
We would then look into it and pass it to devs to get their feedback.

[tradstown]

Could you share an example scene with us here? https://support.chaos.com/hc/en-us/requests/new
We would then look into it and pass it to devs to get their feedback.

Thank you! I'm doing it right now. Have a nice day.

[PROH]

Hi. I'm not sure what exactly the problem is, but if I  understand you correctly,  you're using a 32000px x 32000px bitmap to displace a 10km X 10km area. If that's correct you have 3,2px pr 1meter and that will never give any detailed displacement result.

This isn't caused by Corona, this will be the same for every renderer.

Hope it helps

[tradstown]

Hi. I'm not sure what exactly the problem is, but if I  understand you correctly,  you're using a 32000px x 32000px bitmap to displace a 10km X 10km area. If that's correct you have 3,2px pr 1meter and that will never give any detailed displacement result.

This isn't caused by Corona, this will be the same for every renderer.

Hope it helps

Hello. Yes, you right for the base displacement. But:
Screen size displacement, as I understand working in depends on what you see on the image (pixels), not on texture of the displacement. And yes, I'm using 32K texture for displacement of 10km ground, but also I'm using 8K resolution texture (3m by 3m) for adding details on the top level after main displacement of the ground and it has tiling. So that is a question, how to save more details far from camera and also get good results near the view. That's why I tried to use Real World (units) displacement.

[PROH]

OK. So do you use the 32k map as a hightmap for the hole area like it's done in a game engine? If so, then I wouldn't use Corona displacement for this, but either 3dsMax displacement Modifier or some sort of vertex displacement (depending on the mesh structure).

Regarding the tiled 3x3m map, it's likely to small to be seen from 1 km or more.

[tradstown]

OK. So do you use the 32k map as a hightmap for the hole area like it's done in a game engine? If so, then I wouldn't use Corona displacement for this, but either 3dsMax displacement Modifier or some sort of vertex displacement (depending on the mesh structure).

Regarding the tiled 3x3m map, it's likely to small to be seen from 1 km or more.

Thank you for advise!

About little displacement: look at the images I uploaded in this topic please. You will see, that we will see some details of this little displacement on the middle distance, but it is very blurred because of the displacement

[PROH]

What denoiser are you using, and how is your bump and autobump set up?

[tradstown]

What denoiser are you using, and how is your bump and autobump set up?

It doesn't matter in this case. I need geometry displace. Autobamp has no setup, it is only on or off. There is no bump in the material and I don't use the denoiser

[PROH]

Sorry for the wording. Is autobumb on or of?

[tradstown]

Sorry for the wording. Is autobumb on or of?

That's fine. It is On.

[PROH]

OK. Now I have done some testing myself, and can confirm that displacement on large scale is problematic with Corona.

My test was designed to see how far away you can see displacement sized around 20-25 cm, and in both 4k and 6k renderings I could still see it at 1km distance, even with the denoiser on (Corona). Pictures attached.

But at 8k the problems begin. There is lots of artifacts in the render, and Corona gives a warning about low RAM (I only got 64Gb). Low RAM however should only cause a slow render, and NOT give artifacts.
I have tried to locate the problem, and one thing I noticed is, that when the "Primitives displac." number goes higher than 1.000 M I start to have artifacts.

Hope it helps.

[tradstown]

OK. Now I have done some testing myself, and can confirm that displacement on large scale is problematic with Corona.

My test was designed to see how far away you can see displacement sized around 20-25 cm, and in both 4k and 6k renderings I could still see it at 1km distance, even with the denoiser on (Corona). Pictures attached.

But at 8k the problems begin. There is lots of artifacts in the render, and Corona gives a warning about low RAM (I only got 64Gb). Low RAM however should only cause a slow render, and NOT give artifacts.
I have tried to locate the problem, and one thing I noticed is, that when the "Primitives displac." number goes higher than 1.000 M I start to have artifacts.

Hope it helps.

Hello! Wow, great test! Hope it will help to improve displacement in Corona Renderer and it will help to fix some bugs.

[romullus]

Nice test. Maybe there's a hard limit on overall displacement primitives count?

[GeorgeK]

Thanks everyone, great testing @PROH, I'll be reporting this and we will investigate further, please stay posted for further information.

(Internal id=949812542)

[rowmanns]

@PROH
The issue you reported is now fixed.

You will no longer get artifacts in this case. At 8k it renders correctly now :)

If you exceed the maximum limited primitives you will get an error message too.

You can grab it here: https://forum.corona-renderer.com/index.php?topic=36810.msg203090#msg203090

Thanks,

Rowan

[tradstown]

@PROH
The issue you reported is now fixed.

You will no longer get artifacts in this case. At 8k it renders correctly now :)

If you exceed the maximum limited primitives you will get an error message too.

You can grab it here: https://forum.corona-renderer.com/index.php?topic=36810.msg203090#msg203090

Thanks,

Rowan

Hello Rowan!
This is great news! Also I wanted to ask you about World Sizes type of displacement, is it works fine too?
Also this mistake was with small resolution as well. You can check this image please:

[rowmanns]

Hello Rowan!
This is great news! Also I wanted to ask you about World Sizes type of displacement, is it works fine too?
Also this mistake was with small resolution as well. You can check this image please:

Hi,

Did you send this scene over to us already? If not can you send it over to me? I can send you a link via PM to directly upload the scene to me.

Cheers,

Rowan

[tradstown]

Hello Rowan!
This is great news! Also I wanted to ask you about World Sizes type of displacement, is it works fine too?
Also this mistake was with small resolution as well. You can check this image please:

Hi,

Did you send this scene over to us already? If not can you send it over to me? I can send you a link via PM to directly upload the scene to me.

Cheers,

Rowan

Hello! Yes, I did.