Can you tell me what causes these artifacts and how to fix it ???

[pclavett]

Hi All
Trying variations on my MacDonald terrain and getting some artifacts on the misty clouds near the lake (dark line near the lake edge and below the snow line on the mountain, above the tree line)....think I saw something to this effect earlier but cannot remember where and would appreciate to see if there is an easy fix.
Have tried to ramp up the quality of the atom and cloud to double the max on the slider and did have some improvement but not total resolution of the artifacts and of course....a very slow rendering that would be almost impossible for the whole scene (just rendered a portion of the artifact area).
Appreciate any help !
Paul

[yossam]

I remember a thread with a similar problem, just can't find it. A couple of things............what is your acceleration cache setting, do you have DOF on? I'll keep looking.

[pclavett]

Thanks Yossam for the help and to answer your queries....no acceleration on all clouds (none-highest detail) and no depth of field applied.
Will also keep looking as I remember a thread about something similar but the search unfortunately gives me all sorts of results but not the right one !
Thanks !
Paul

[Matt]

It looks like it could be this:

http://www.planetside.co.uk/forums/index.php/topic,17307.msg168100.html#msg168100

Matt

[cyphyr]

It looks more like the issue Dune pointed out in his last post on the beta forum:

[removed by admin: please DO NOT post alpha site links in the public forum]

(non beta testers will not be able to access this link)

[pclavett]

Thanks Matt
He is your reference:
"With adaptive sampling, RTO, and atmo/cloud not deferred, objects obscured by atmosphere have outlines. Presumably this is due to incorrect comping of interpolated values. The outline can be prevented by enabling defer atmo/cloud or by rendering with max samples (non-adaptive) pixel sampling. This bug is in 3.0.05.0 and 2.5, and may much older than that."
Rendered with the second option setting: "..... by rendering with max samples (non-adaptive) pixel sampling."
This did the tick with complete disappearance of the artifacts.
Thanks again to all for your insights.
Great weekend to all !
Paul