Hi All
Decided to remove my confusion on this with some agricultural tests on object quality settings in populations. Two side by side populations of the same object. One set to highest quality, the other to medium quality. I'm not going to tell you which is which... that way you can make up your own mind on the differences ;)
No soft shadows
Smooth object normals off
Bark texture tiled to 1000pixels/m
Render settings: Detail 1, AA 4, GI 2,2 (I'd prefer higher GI quality but it's good enough for the purpose of this test)
Distances from camera to centre of populations: 400m, 95m, 33m (still rendering)
Extract from log file for each population (irrespective of distance!):
16 objects (0.00214 billion triangles) inserted by Populator "Pop WE04a.obj"
For comparison, from a render using billboard trees:
760439 objects (0.00608 billion triangles) inserted by Populator "Pop 2d card.tgo"
Still to do:
* Render detail/aa settings
* Render time/memory usage comparison for different quality settings
* Minimum distance to replace tree models with billboards
The trees on the right appear to have deeper shadows, but I can't tell if that's the placement or the render quality. I would like to see the results with a higher AA setting.
The shadows will vary a bit as I used a default camera (fov = 60°). Next time I'll mix the populations to ease comparison across the scene. As it is I still have to toggle bounding boxes off and on to find which trees are in which group.
For now, this test is just looking at any visible differences as a result of just the Render Quality setting in the population node. I'll look at different Render settings later, and when I get an optimised value for those I might repeat this series. For now it's looking like there is bugger all difference between them with these render settings so I could have saved myself a lot of time with previous projects ;)
Is the medium quality population on the left or right?
I'd say the higher quality ones are on the left.
The difference in lighting angle makes the comparison pretty difficult.
Honestly, I can't tell :), you may have to wait for the closeup to notice a difference? What's the render times?
I think the population quality settings will have a much greater effect at longer distances where the LoD routines come into play more.
- Oshyan
That makes sense from what Matt or Jo told me the last time I was looking at this. I thought I noticed some difference but never got around to a side by side test. The distant shot is probably getting close to the distance where I can start using billboards so it's quite encouraging that the differences are so subtle at this distance.
I can remember getting trees without leaves in the distance on some older tests, so there may also be a link to the Render detail setting (from memory I had detail turned down a lot for that to happen).
Quote from: JohnnyBoy on September 10, 2007, 10:00:49 PM
What's the render times?
6hrs 45 min for the large image, the distant render was cropped and was only about 20 minutes. Stopping the closer render now, about 1/3 complete after 6 hrs.
[edit] finally stopped the render. Here's a portion with one tree from each group
OK I think this illustrates the effect of the setting better... Pushed things back to 1km, increased AA to 6 just for the hell of it since it was a smaller render. The visibility of the different settings appears to be dependent in part on the render detail level. If you have a high detail, you can use low render quality in the populations without losing much detail. ... and if you use low render detail to speed up the rest of your render, you can bump up the quality of the objects so you don't lose too much detail there.
Cropped renders from the same size image as above.
Max and medium quality populations, Render detail 1
[attachimg=#1]
Max and low quality populations, Render detail 1
[attachimg=#2]
Max and low quality populations, Render detail 0.5
[attachimg=#3]
Max and low quality populations, Render detail 0.25
[attachimg=#4]
I wanted to try this with a more distant render.
Row 1 has a render detail: of .25, Row 2 has detail: .5, Row 3 detail: 1.
The four columns are the different object settings.
Render times ranged from tens of seconds to almost 40 minutes.
Were the differences in render time for render detail = 1 significant?
You might be interested in a page I created a long time ago. Not that it has much to do with populations, but mroe to do with comparisons of render settings.
http://motionmagnetic.com/a_terragen2/render_examples/render_examples.html
Quote from: bigben on September 11, 2007, 10:34:43 PM
Were the differences in render time for render detail = 1 significant?
Yeah, compared to detail .5 they took over three times as long to render.
Here is a full list:
Row1(.25): 1:08s 1:13s 1:47s 3:48s
Row2(.50): 2:14s 2:31s 4:14s 9:25s
Row3(1.0): 7:04s 8:10s 13:34s 38:19s
That's still quite encouraging, because with detail = 1, the trees don't appear to have degraded that much with low quality in the population and the times are seriously shorter.
It's also apparent, that in this situation, there is no reason to use the highest quality for populations - even with low detail settings.
I would have thought the opposite actually... ;)
I know some people drop the render detail down to shorten render times where rendering clouds is an issue. Using the higher quality settings for populations means they can also keep their trees looking good without too much overhead. It would be a personal preference as to how much degradation they are prepared to put up with, but at least the option is there if you want it.
Not sure if we are talking about the same thing, but can you see a significant (or any) difference between High and Highest settings, I sure can't. 8)
It's a little hard to say as they're not the same area. Try rendering the same are with both, overlay the images in Photoshop and set the top one to difference. The highest quality one looks a whisker denser but that may be an illusion... and of course, it would also "feel" better to someone choosing it :)
The fact that you have a number of options to sort out your own preferences for the compromise between render time and quality is pretty neat.
Lots of useful info in here I've been looking for, for a long time. I love this website :)
Ok, just had to try it. Rendered with detail .8
Row 1 is rendered with High population quality.
Row 2 Column 1 has a second render at High to use as a control.
Row 2 Column 2 is rendered with the Highest population quality.
Row 3 is Row 2 set to difference over Row 1.
I'll have to try this with a lower detail setting to see if the difference is greater. I don't see too many instances where I would use the highest setting, but to each their own. ;D
Enlarged:
If you auto-adjust the levels of this you can see the noise from the difference. It is subtle, and you'd expect it to be greater for lower render detail settings. Whether or not it's worth the extra time is up to the individual. For some effects, I'd be prepared to double render times for a subtle improvement but for others I wouldn't.
At least now I have a better understanding of what the settings actually do and how I can use them. With the time I'll save I can bump up AA to get better looking trees up close. :)
Just finishing up,
Render Detail .2