The Moon Illumination / Color Gamut Help needed

Started by Martinnn007, July 18, 2021, 12:50:20 pm

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Martinnn007

Hello everyone,

That's my first encounter with the forum and I hope I'll make a clear description of my problem.

I just started working with Terragen and as I'm a filmmaker myself, I wanted to learn creating realistic environments and found Terragen to be really really good.

I've created Moon-like object with no atmosphere and sharp, low-positioned lighting.

1.On each frame the illumination seems to be different, especially in the craters, what could be the problem? I followed PlanetSide's tutorial on render settings for animation and tried to use recommended settings.

2.Can you simulate a flat (Log) color profile for further color grading process in post-production? Is there any way to increase the flexibility or dynamic range? It's mainly because I do a lot of Rec 2020 PQ, HDR delivery and was hoping to get something similar to what a cinema camera can do. (Main problem is that sometimes highlights are blown out)

3.Also, the 8K frame doesn't look photorealistic to me, it seems a bit sharp and highlights look strangely contrasty. I used detail rendering at 0.8 and AA at 8. Took me 14h to render it haha

I'm attaching a low-res test video and an 8K frame of a previous version of my project (I adjusted lighting a bit).

It's also a pleasure to join you guys and hope for a great time spent in this community.

Many thanks,
Martin

WAS

Have you generated cache file(s) for the scene to stabilize the lighting calculation? That can help a lot.

Also for film, and post production I would use the soft AA method, not the recommended settings as its using reconstruction of edges. Soft AA allows you to go in and sharpen what needs to be, or to a more satisfactory level. If you are doing denoising it also helps woth rogue highpass effects on hard edges that are already sharp. 

For contrasting maybe playing with the soft clip, and contrast of the scene can help.

WAS

PS; also try using bright colours as opposed to a brighter sun (though I don't know if that's what you're doing)

Dune

Welcome! Good to have you on board. A few more thoughts; I think micropoly detail needn't be that high; 0.5 would probably do well enough and create less harsh details. It would also save on rendertime. Probably even AA can be 0.6. You didn't use Path Trace on this? No need for a scene like this. Default (standard) renderer would be much faster and good enough.
If you have reflection on the rock, it could also blow out the lights, and increase the contrast. You could try decreasing reflectivity.

Martinnn007

Thank you guys for the reply.

So far thanks to @WAS I learnt to do the cache files for the scene which alone helped a lot with the illumination. It seems lot more stable between frames.

@Dune , I've tried to decrease the contrast by lifting the sun a bit up and lowering its brightness. I'll still test different settings and try to find the best solution.

With the harsh terrain I think it might be a good idea to decrease the details as you suggested.

Do you think it'd be better to do a 2K video with almost maxed details or 4K version with middle-to-high settings?

Martinnn007

Quote from: WAS on July 18, 2021, 12:57:13 pmHave you generated cache file(s) for the scene to stabilize the lighting calculation? That can help a lot.

Also for film, and post production I would use the soft AA method, not the recommended settings as its using reconstruction of edges. Soft AA allows you to go in and sharpen what needs to be, or to a more satisfactory level. If you are doing denoising it also helps woth rogue highpass effects on hard edges that are already sharp.

For contrasting maybe playing with the soft clip, and contrast of the scene can help.
If you could just tell me where do I find the soft AA method, denoising and soft clip?

not sure if I'm familiar with these settings

Martinnn007

Quote from: Dune on July 19, 2021, 01:26:03 amWelcome! Good to have you on board. A few more thoughts; I think micropoly detail needn't be that high; 0.5 would probably do well enough and create less harsh details. It would also save on rendertime. Probably even AA can be 0.6. You didn't use Path Trace on this? No need for a scene like this. Default (standard) renderer would be much faster and good enough.
If you have reflection on the rock, it could also blow out the lights, and increase the contrast. You could try decreasing reflectivity.
I've had the additional reflexions before as I thought that the moon is itself very reflective but I disabled it. I actually also changed the colour of the surface from bright to dark but now it doesn't look like moon to much. Need to perform more tests and find the best settings as I would prefer having a very contrasty, moon-like scenery for realism but the rendered image is to sharp and blown out.

Can upload current sample frames today so you can tell me if I'm going the right path :)

Dune

Soft AA is referring to one of the filters in the render tab, best to do some small (crop) tests which each filter, and see what's best. Cubic _Bspline is soft. Soft clip can be found there too, raise a little at the time and see if it reduces harshness.
Some people also work with more suns, one visible at a certain strength, another for lighting the surface, or even another for lighting atmosphere. You can adjust altitude a little, without it being noticed.

WAS

I'd say the most problem with shadows is your terrain is very rough, and has a lot of crusty-displacement bits which will create hard shadows. You'll probably want far less roughness to your displacements.

Here is a quick attempt I did: https://drive.google.com/file/d/1UZ97Z1sfjd8eCGs1A_Rs-45AwSHCrzI2/view?usp=sharing (download for lossless quality, though AA3 was clearly not enough for the starburst filter. Yucky.)

Matt

July 22, 2021, 02:21:23 am #9 Last Edit: July 22, 2021, 02:28:46 am by Matt
Hi Martin,

1. For animation render settings, this might be useful: https://planetside.co.uk/terragen-tutorials-for-vfx-series-5-rendering/terragen-for-vfx-part-24-render-settings-quality-details/

2/3. If you're intending to post process the images and want the full dynamic range, I recommend saving to EXR. This will contain unclamped, HDR "scene linear" data. If you want log space it should be possible to convert to that in your post production software.

Terragen applies a soft clip (by default) to roll off the highlights, but this only applies to the low dynamic ranges images seen in the 3D Preview and Render View, not the EXR files. It's assumed that you will apply a LUT of some kind when working with EXRs in another application. If you don't, you'll get this hard clamping/clipping on anything brighter than 1 when viewed in another application.

If you can't work with EXR and need to use a low dynamic range format (e.g. TIFF) for some reason, make sure you have "Soft clip" enabled in Terragen. It's on the "Tonemap" tab of the render node. The default softness is 1 but you can change this.

We also have OpenColorIO integration, in case that's useful to you: https://planetside.co.uk/wiki/index.php?title=OpenColorIO

Just because milk is white doesn't mean that clouds are made of milk.