cloud artifacts ?

[sirio]

Hi,

Rendering very high-res pictures (over 4k by 4k) I noticed artifacts in my clouds (attached example).
I tried to play with quality parameters (in render, in the clouds, in the atmosphere) as well as GI settings but no results.
Is that a limitation of TG at those resolutions or is there anything else I'm completely missing ?
thank you

Sirio

[choronr]

Might be you need to increase the amount of 'samples' to reduce the noise.

[Tangled-Universe]

The "quality" setting in the cloud node controls with how many samples the cloud volume will be sampled.
Usually this sample number was shown, but it mostly caused confusion rather than that it was of any help.
So that's why it's just called "quality".

Usually, in many cases, a setting of max 1 should give good results.
You can try higher for crop renders of problematic areas, like 2 or 3.

However, if I look at the image I think you can't really smooth these out, simply because there isn't much detail in the fractal in combination with low cloud density (probably).

If you can't get the results then you can post your tgd project file here for troubleshooting.

Cheers,
Martin

[Oshyan]

That noise actually looks a little odd to me. As-in it's unevenly distributed. Not all of the edge of the clouds has the same level of noise, as far as I can see. That could be due to several causes, perhaps there are multiple cloud layers used with different settings for example. Certainly this level of noise is not normal or a fundamental limitation of Terragen. But without knowing more about the scene and settings it's hard to make more specific recommendations.

- Oshyan

[bigben]

Possibly some small fractal detail that wasn't visible on smaller renders? A cropped render (to save time) at a larger image size would confirm/eliminate that.

[Tangled-Universe]

I'm pretty sure it's a combination of low'ish density of the cloud layer itself in combination with the fractals soft edges with less detail.
I have seen this for years in my renders too.
In these specific cases the renderer has a hard time to make it all appear smooth.

[sirio]

Thanks for your answers. I checked quality settings and to me they appear to be ok.
Attaching the tgd file so you can check yourself.

Thanks
Sirio

[Hannes]

Your cloud quality settings are set to 0.6. This might not be enough. Try 1 or even 2.

[sirio]

After trying to increase cloud (not render) quality to values over 1.3 the noise disappear and clouds are now all soft and really high quality.
Not sure why that happens, as in some other renders - same resolution but lower cloud quality I have no problems with noise.

I hope this can be of help for somebody

Sirio

[Oshyan]

There are certain settings like Density and Edge Sharpness that require higher cloud Quality to minimize noise.

- Oshyan