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Messages - matsu

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1
Alright! Will give it a go.
I must be mistaken then (and my colleagues as well). Clearly remember being able to produce nice fog (with noise) when inside a volume, without using global volume material. It's a pain setting up an animation where the fog volume has to move with the camera.

Feature request removed. Will make a separate thread about that once I've tried Corona 10.

2
I haven't used the volume material to create fog in a while, but the behaviour isn't what I remember. Maybe this is a bug.

When using a volume material, it can either be assigned globally (in the render setup) or locally to an object. The "On Surface" mode is quicker, but only works when the object containing the volume effect is seen from the outside. However, when setting it globally, it works no matter the camera placement. So far so good.

The other option is to use the "Inside Volume" setting, which is significantly slower (more than twice the render time in these examples!). It works as expected when set globally, albeit slow. It works when seen from outside the object when used locally. When seen from inside the object it does not render correctly! Afaik, it was previously possible to place the camera inside the volume, and render correct volume effects. Is this a bug??

It's also interesting to see the difference when applying noise. With "On Surface" the result looks... extremely poor. With "Inside Volume" it looks great. I remember it as being a lot more similar.

The scene here is a simple box (gray CRN PhysMat) with some holes in the roof, a daylight with CRN-sky, and an editable poly object containing the fog.

Win 11, CRN 9 HF1, Max2023

3
Great! Problem solved. Had no idea that page existed.
Still, having to install all of Vray just to get the converter to work seems rather inconvenient. Wish the converter would work without Vray installed.

4
The converter is unable to read/convert materials and maps from Vray unless you have Vray installed.
In the past, this issue was solved by installing the Vray demo, and even after it expired, the converter could use it to read Vray materials.

Since Chaos changed their policy, Vay is now a one-time trial, and it's not possible to download it again once your trial has expired.

This poses a problem when you update 3dsmax or get a new computer, since you cannot download Vray again. I see no other option than having to buy the full version of Vray... which really isn't worth it to me. This does imo defeat the purpose of the converter, rendering it useless.

Do you see any other solution? I think Chaos ought to be able to include the files necessary to make the converter fully functional without having to install Vray.

5
Agreed. It would help A LOT.

If this can be done fairly easily "by hand", surely Corona should be able to apply the same fix automatically "under the hood"?

6
I've tried with and without noise mod; with different textures; RWS and not - it persists. Even tried world size displacement.

But I think it's strange you get this obvious repeating/tiling pattern. With the old displacement you could just lower the quality - sure, you'd lose detail, but you wouldn't get artifacts like this. If you can reproduce it, I hope you can sort it out.

7
Hey Matsu, what is the topology of your plane? Is it equally subdivided, can you please provide a wireframe?

It's a plane primitive 3x3m, 30x30 division (+Noise modifier Scale=20 Strength Z=60mm) - so 100x100mm squares. Adding wireframe.

Quote from: romullus
You need to set lower screen size in 2.5D displacement, or higher in classic one, to get comparable results. If i'm not mistaken, the ratio is about 1:1,5 So 1px classic displacement, should have about the same quality as 0,67px 2.5D displacement.

Adding comparison on 0.5px. The artifact is still there, but not as pronounced.

8
I'm adding this to the thread, even though this isn't strictly about curves, but rather about the 2.5D displacement in general.

I just tried setting up a simple textured lawn thing, and noticed some strange artifacts. Tried to see where it was coming from, and I realised it was coming from the 2.5D displacement. Tried changing to 3D and it's a huge difference.
It's just a simple JPG file, loaded with CoronaBitmap at gamma 1.0 and the bitmap size is bigger than the sample plane, so no repetition there. Displacement is at 1px in both cases.

Help/suggestion?

I think I will consider using 2.5D only in cases where memory is an issue, since the look is significantly worse. :(


9
we are working on a fix.

How is it going? ;)

I am right now designing a material, and was going to randomize displacement with "element" mode, but wasn't able to. Using "MaterialByElement" kind of works, but it then appears as if the Gamma Randomization has no effect. It would be absolutely great if this worked. Thanks.

11
a checkbox for rendertime only would be great, but instead of a global setting, it should be set per distance map.

Agreed! I don't really use distance map due to this reason.

12
I was really stoked when I read about the displacement improvements that came with the latest version. However, I've tried it out some now, and I'm actually bit disappointed.

I'm sure the latest fix has improved the look of irregular disp-maps, but the way I use it (in archviz) is to produce pronounced details on buildings, which are almost always sharp and regular.
In the image I use the same basic brick texture, but on some parts of the facade, the architect wants a striped pattern. Since the meshing of the displaced areas is triangulated and random, the edges get very jagged, and the shadows look... really bad.
This kind of thing worked a lot better with Vray's 2D displacement. (I don't have any experience from using Fstorm.)

In the image, the displacement is set to Screen 1.5px, but many times, the scenes are too large and too complex to use such a small value. (I'd love to be able to increase it per object, or even use Screen and World on different objects!)


A possible solution I could think of is that Corona considers the displacement map's contrast to decide where to add triangles. So, if there's a sharp contrast between the pixels in the map, Corona adds more triangles, and vice versa. Adaptive meshing based on dispmap contrast. Edit: Did a quick test, and noticed it already does this. Added another image where I used a checker map to displace a tessellated cube. It shows the problem, and how displacement tries to solve the issue. 1px displacement in this render, but artefacts remain no matter the setting.
One could also think that the meshing uses some kind of "loop detection" to follow the shapes of the dispmap.


Another thing I been thinking about is the option to use "displacement LOD" - an option to skip displacement if the the displaced geometry is too small (too far away). Right now, displacement can really destroy the look of displaced mesh that is too far away from the camera.
The only solution now is using different materials for different shots of your scene, but is just too cumbersome to be a practical solution, and using World scale just isn't an option due to memory use.


I really hope you keep working on this. For me, it's one of the areas where Corona is lacking compared to other renderers.

13
[Max] I need help! / Re: IOR for unfinished wood?
« on: 2018-08-17, 13:59:19 »
Make it really rough (like 0.25 or something) and add a bit of bumpmap. That usually works for me, anyway.

14
[Max] I need help! / Re: Massive 90k pixel rendering size
« on: 2018-08-17, 13:57:22 »
I've done 4x5m banners, and the client insisted on 150 dpi. Problem was they asked for this AFTER I had already made the images in normal print resolution (6x4k px) with hundreds of layers and stuff.
I scaled the images up in Photoshop, to the desired resolution. Client was happy that the file has "150dpi" when they look at it in PS, and the prints look great.

15
Haven't downloaded any of these (yet), but thanks for sharing!

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