Another Path Trace comparison

Started by zaxxon, November 26, 2018, 12:13:33 pm

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zaxxon

Thank you Matt and Oshyan for this great program and the new render enhancements! My first go-round with the new path tracer options: I selected a past project (https://planetside.co.uk/forums/index.php/topic,21654) that had large areas of deep to moderate shadow, and lots of vegetation. As expected the shadow detail is now much more 'illuminated', and the vegetation seems more 'vibrant'. The cloud clip files are a bit different in the versions, but it's the terrain lighting that is the subject of the comparison. I was surprised at how much additional light was revealed in the shadows, as a compositional strategy the lowered contrast (or perhaps - more 'evened') needs to be a consideration going forward. But I'm really pleased with the ability to bring more detail into shadowed areas without additional 'suns' or some such 'cheat', this is a significant gain in realistic lighting of natural scenes, thanks again.  The render settings were set to "path tracing on surfaces" and .8/8 with the M-N filter.

otakar

My goodness, that's a huge difference! Not only are more parts illuminated, the trees themselves - leaves - are a lot brighter as well. Essentially, it leaves a very different impression, as in the original render the hard (rock) and ground surfaces receive much more attention, whereas in the PT render it's a great deal more evened out as you already mentioned. This is maybe the render with the greatest PT impact I have seen yet. Thanks for sharing!

archonforest

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WASasquatch

Whoa! You didnt change tbe lighting? Thats amazing the difference. Night and day. PT version for sure is much better.
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Oshyan

Nice to see you trying out this new option! Certainly the path traced version looks much nicer to my eye, more realistic and well shaded overall. But beyond that I don't think it's entirely useful to compare the two due to the clear difference in lighting. I can say with fair confidence that the majority of the overall change in lighting is not coming from path tracing (after doing somewhere around a zillion tests myself :D). Perhaps the original image used multiple suns and you've removed/disabled that for the path traced version? Or perhaps it's just the change in clouds, which can certainly have a notable impact on lighting.

I'd also say the "contrast" in the path traced version is actually higher, for example the darker areas of dense trees are now *darker* than they were, while the light areas remain light. That's increased contrast, right? But regardless those changes certainly do need to be taken into account when setting up images, especially for those familiar with the non-path traced output of old.

- Oshyan

zaxxon

You may have a point Oshyan as I had a number of variants that were close. I'll double check the files to see the sun angle etc, but there is only one 'Sun' in the second image. I definitely like the PT lighting.

Jo Kariboo

Impressive difference. It is an enriching experience!

Dune

I also thought you had a different sun angle at first, but apparently the main sun is in the same position. The difference is astronomical anyway.

Oshyan

The sun appears to be in the same position judging by shadows onto the terrain. So it must be the clouds or something else.

- Oshyan

WASasquatch

Judging by my experiments with deserts and high contrast grounds, it seems PT and exaggerated surface details (maybe one or the other) adds extra lighting from ambient sources + direct.
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bobbystahr

something borrowed,
something Blue.
Ring out the Old.
Bring in the New
Bobby Stahr, Paracosmologist

DocCharly65

I think the clouds have moved a bit so the light changed but anyway: WOW!

Oshyan

I know you've said this WAS, but I have seen little to no evidence of it myself. The comparisons always seem to be just different enough in the rest of scene setup to not seem truly, fairly comparable. Perhaps Matt can weigh-in on whether it makes sense this might happen from a back-end technical perspective. The only 2 things I could see affecting this notably with path tracing enabled are 1: anything that is reflective, since path tracing uses a different reflection/specular model, and 2: anything that renders differently with Defer All (which you can test on its own without path tracing). If this is really an effect of PT I'd love to know about it because we'll need to include it in any usage notes.

- Oshyan

Matt

It is a different scene (different clouds casting fewer shadows, and different surface shaders), but I can see some improvements in the shadows from the path tracing.
Just because milk is white doesn't mean that clouds are made of milk.

Oshyan

I certainly see the improvements from path tracing, regardless of other aspects being difficult to compare directly.

- Oshyan