SuperFly shadowing inaccurate away from scene origin



  • @anomalaus Ok, when you are using refractive materials and do rely on Cycles caustic calculation you have to life with its limitations. Or in other words, shadow rays are terminated when they hit a surface with refraction and can therefor not collect lightning information through this optimization pass. What the tricky glass shader does is: You are a shadow ray, fine for you i am transparent.



  • Don’t know about performance for 32 versa 64 bit floats on a CPU. Back in the day when we had the x87 FPU everything was calculated internal with 80 bits. With SSE this changed as we now have native 32 and 64 float support.
    About storage size, thought the smallest memory allocation for a variable on a 64 bit app is 64 bit. But i can easily be wrong here as i am out of such compiler internals since a long time.



  • The only suggestion I have is this
    Put your hrdi on the background material, not a sphere.
    Use an area light for the sun.

    There has been discussion that a sphere doesn't have all the render info with it.
    I'm not entirely sure of all the details, but it makes sense that if a sphere leaves out render info it would mess up.



  • @shvrdavid any further clues on what topic that would have been discussed under, so I can search for it?

    That's also going to be difficult if I want to have a cloud sphere casting sun shadows.



  • @shvrdavid while I was thinking about the transition from an infinite light to an area light, which I'm reluctant to do, since area lights are exclusively rectangular in the first instance, unless you meant to make something with geometry into a light emitter, I ran across an old post from @bagginsbill on Rendo in 2006 regarding a Light Meter. None of the links currently work, but the concept should be an excellent tool for matching the different lighting levels which result from area lights/mesh emitters vs infinite lights.

    Prior to setting up the color ramp nodes which the light meter consists of, I made a quick and dirty replacement, turning off the infinite sun light and slaving it's colour and intensity parameters to a cycles emission node plugged into the cycles root on the pre-existing sun sphere in my scene, which was already a light emitter, but was only using volumetric scatter and a glassBSDF node to give a nuanced image of the sun's disc when viewed at the horizon. With a prop as an emitter, the preview isn't illuminated (no big deal since I can change the preview mode), and the light isn't anywhere near as strong (due, no doubt, to inverse square light propagation being applied to the mesh light which wasn't applied to the infinite light), but the far-from-origin shadow artifacts are still evident, as they were when I'd made all of the environment spheres invisible in a previous test, so I don't think switching to the background for scene lighing will help at all.
    ***NSFW content***

    click to show

    Still the full complement of shadow artifacts at 406m from the origin. Sun Sphere at 2.77 intensity.



  • @shvrdavid Uhhh, no. Area Light for Sun doesn't work for me at the distance it needs to be to give sharp shadows (and subtend 0.53°) and approximately parallel rays.
    ***NSFW content***

    click to show

    I probably went overboard with the emissive sphere's intensity (2765 = 1000 x the infinite light intensity), but it's a lot closer than the overcast appearance in the previous render, which admittedly is mostly clear of fireflies. Can't win. Can't break even. Only thing left is to get out of the game D-X.



  • @anomalaus said in SuperFly shadowing inaccurate away from scene origin:

    @shvrdavid while I was thinking about the transition from an infinite light to an area light, which I'm reluctant to do, since area lights are exclusively rectangular in the first instance, unless you meant to make something with geometry into a light emitter, I ran across an old post from @bagginsbill on Rendo in 2006 regarding a Light Meter. None of the links currently work, but the concept should be an excellent tool for matching the different lighting levels which result from area lights/mesh emitters vs infinite lights.

    If you're talking about BB's Light Meter, you'll find it as the 4th item on this page of this "File Cabinet" --> https://sites.google.com/site/bagginsbill/file-cabinet



  • @miss-b cheers! I would have looked there eventually, but I was a bit distressed that I couldn't find a single thread older than August 2018 on Renderosity with their search, despite google finding the thread which mentioned the light meter. Of course all of the links within the thread were dead, hence my question.

    @nagra_00_ well, turning the groupingObject hierarchy on it's head did what I needed, bringing the scenery to the character, within close proximity to the origin and making the shadow artifacts go away.
    ***NSFW content***

    click to show
    though, of course, I still need to deal with render quality issue, but that re-enters the realms of possibility when the shadow artifacts are gone. The Sun angle's slightly different, but I think I can live with this solution.

    In truth, I really only need the sun sphere prop if I intend the sun to be in frame, such as a dawn or dusk situation, or when I want low angle "God rays" from cloud shadow.

    I'll have another go at the main render, and see if any of the other issues like the second skin water droplet figure rendering completely black has gone away too.



  • Side note: You can control the light fall off for light emitter by using the LightFallOff node. Something like this:
    0_1542124053191_lfo.jpg

    However i doubt that an emissive sphere works better with caustics. Placed in the distance it can be considered to be small and Cycles will have the same problems to hit it by random rays.



  • @anomalaus said in SuperFly shadowing inaccurate away from scene origin:

    @miss-b cheers! I would have looked there eventually, but I was a bit distressed that I couldn't find a single thread older than August 2018 on Renderosity with their search, despite google finding the thread which mentioned the light meter. Of course all of the links within the thread were dead, hence my question.

    I'm just the opposite. I'd rather go where I'm "fairly" sure I'll find something, than to go "searching" for it. In this case, I remember it still being active on his site, so that's where I would've gone to get it, if I didn't already have it. ~wink~



  • @miss-b interestingly, the thread I'd found from 2006 had a much earlier version of light meter prop
    0_1542167337709_Screen Shot 2018-11-14 at 2.47.41 pm.png rather than the more familiar one from 2011 which I found I'd already downloaded when it came out years ago
    0_1542167470727_BBLightMeter.png



  • @anomalaus I don't think I ever had the earlier one, but I have had this one for a while now.



  • @anomalaus said in SuperFly shadowing inaccurate away from scene origin:

    @shvrdavid any further clues on what topic that would have been discussed under, so I can search for it?

    https://forum.smithmicro.com/topic/2086/submit-your-poser-suggestions-to-smith-micro/977