More important; detail or anti-aliasing?

[jbest]

Hey everyone,

just a quick question. Which is more important in a realistic terragen 2 picture, detail or anti-aliasing?

Thanks
Jahnu

[rcallicotte]

In my opinion, detail.  But, it depends on what detail.

Detail should be at least .7, but I prefer .9 or 1 for a final render.

If I have this wrong, someone please correct me.  For closeups, I like more GI Sample Quality.  For broad sweeping large scenes at a distance, I like more GI Relative Detail.

I always use some strong AA, though.  I rarely use GI Surface Detail.

[Tangled-Universe]

Calico more or less says it.
Important is what kind of scene you have:

Terrain only = detail
Objects only = AA
However, you often have terrain + objects so then both are important. A good mix of detail and AA settings is key for getting good quality and WITH decent rendertimes.

Generally, a quality setting up to .9 is the max you'll need for your terrain-displacement with many small scale details.
For rough terrains with large features a setting of around .7 often suffices.

I will prepare an AA-setting comparison chart soon, since I think people need a reference of the results they will obtain when using different settings for AA to render populations of trees and grasses. My latest scene has a few good spots to test this on.
Basically I can tell you that AA6 with maximum samples is the most bang for buck. AA8 is quite slower and looks just a little bit better, but not enough.

IMPORTANT: if you render an "object-only" scene without visible terrain you should still need a good detail level, since the GI quality is coupled to the detail slider. So if you have GI set to relative detail @ 2 and sample quality @ 4 and you're rendering with detail 0.5 then the effective GI settings will be:
0.5 x 2 = GI relative detail = 1
0.5 x 4 = GI sample quality = 2

This more or less always forces one to use higher detail levels than necessary in order to obtain good GI.
It would be ideal if the detail slider would be un-coupled from the detail setting.
As far as I know this would mean quite a change in the renderer.
(the detail setting controls the level of subdivisions for geometry and shading is done after this, thus also GI)

[domdib]

Interesting info on the coupling of the detail and GI settings. Thanks!

[Henry Blewer]

This will be handy. I want to do a new POV and render of Cherry Hill. The bmp file is not to bad, but the jpeg versions are not so great. I did save it in OpenEXR, buit Blender is the only program I have which can handle OpenEXR.

[rcallicotte]

Cool!

And thanks for a more detailed explanation.

I will prepare an AA-setting comparison chart soon, since I think people need a reference of the results they will obtain when using different settings for AA to render populations of trees and grasses. My latest scene has a few good spots to test this on.

[Tangled-Universe]

The first part is ready of the comparison.
It contains rather close-up to mid-distanced objects.
I will probably render another series with mid- to far-distanced objects, with the same series of settings.
Luckily you can animate these settings, so it takes very little time to set this up

[warnerbrown]

Thanks for the info. On some shots in my film I had to render at .45 or .5 to save time. So this is great to know for the future, when I have a better system going.

[JonathanBishop]

I've also found that samples in atmosphere and clouds make a huge difference in quality of your renders.  I recently was working on a scene where I had to put Atmosphere samples up to 512 to get good renders.  Otherwise, the sunlight coming through the clouds would come out very blocky.  Increasing the AA also helped a bit, but not near as much as upping the samples.

Oddly, upping the samples also increased the brightness of my haze a bit, but I could only tell when doing direct comparisons.  Keep in mind, though, that raising the samples that high will increase your render times drastically.  I went from around 4 to over 7 hours for a 1024x1024 when I went from 256 samples/AA 5 to 512 samples/AA 8 both at Detail 1.

[Oshyan]

512 atmosphere samples may be "necessary" to completely remove noise in some cases, but it's generally fairly impractical to actually render at that level. I'd suggest instead using "Raytrace Everything" with an atmosphere-only pass (turn off surface rendering in the planet node for example), and then combine this with a terrain-only render using the normal renderer. In an upcoming update there will be an option to raytrace *only* the sky, which should make this optimization a lot easier to use without separate render passes. In this raytraced atmosphere mode, it is the antialiasing which generally controls your noise level. When using Raytrace Everything (or, in the future, Raytrace Sky), do *not* use extreme atmosphere or cloud sample levels; instead use normal or even low levels and adjust antialiasing to deal with noise. An AA value of 4 or 5 should give fairly low noise results for example, even with complex atmospherics and an atmosphere sample level of only 32.

- Oshyan

[Tangled-Universe]

To add a bit to Oshyan's good advice:

If you render a "ray trace everything" (RTE) pass with atmosphere and visible trees (you might need to render a slightly bigger crop to get an overlapping piece to match/blend the seams in post-work and this overlap can contain trees) then you can choose to keep your AA the same in order to retain the render-quality of your trees. So say you've rendered with AA6 then keep it at AA6.
However, in turn, reduce the atmosphere/cloud samples accordingly.
If you render at AA8 then you should reduce samples again.
This way you save un-necessary long rendertimes while keeping quality good.
(Basically there's a kind of inverse correlation between AA-value and atmo/cloud samples when using RTE or, later, ray trace sky.)

Perhaps in the near future the sticky render settings recommendation thread should be updated about this way of rendering.