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TobyGaines

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Everything posted by TobyGaines

  1. Refraction in AOV Houdini 16.5

    looks like all_refract and indirect_emission are what you need "all_refract" doesn't seem to be in the dropdown list or it's named something else - all you have to do is put all_refract in the vex variable slot. indirect_refract seems to work too
  2. Help With Speeding Up Render

    I was using Raytrace, not PBR, because that's what your scene had, but they render this the same - micropolygon looks even worse I think it's the principle shader with GGX that's causing most of the problem - when I use classic shader core with Phong, there's no noise. This is one of the cards under your petri dish, no reflection ( I cranked up the gamma, on both, to show it better )
  3. Help With Speeding Up Render

    Here's what you see when you go from 0 transparency to 1. First image is an opaque, black shiny shader, the second is just switching transparency to 1.0 ( open to full size to see it )
  4. Help With Speeding Up Render

    sweet jesus, forget what I said before, this is much more of a nightmare than I thought! I finally got a faster render, but the rabbit hole kept getting deeper, so it took longer & longer to work out With both the principal and classic shaders / GGX, refracting Reflection rays gives a ton of noise, independent of roughness settings. The noise needs high Pixel Samples and increased Refraction Quality settings to fix. Specular from lights is the worst, as implied by light sampling issues mentioned previously - so I turned the light's reflection contribution off and replaced it with reflection cards. Switching the Refraction Model from GGX to Phong helped a lot ( I haven't found a switch in the principled shaders yet so I had to use classic shaders ), there's still a fair amount of noise but now it seems to shade like I expect it; increasing Max Ray Samples was actually effective, and at only 12, which allowed me to reduce the Pixel Samples down to 8. Noise Level worked fine at the default 0.01. Reflection and Refraction Quality needed a boost to 2 and 4 respectively. Limits panel was left as is ; reflect 2, refract 4, Color 4. I was able to cut the render time in half after all this ( changing the shaders to classic to switch off ggx did change the look ), but that's still way too slow for what it is, there should have been no noise in the first place. Stochastic transparency on / off and high samples made 0 difference Sidefx has to fix this! Using a different renderer is certainly a good idea in the meantime I still want to try it with a fresh scene, and in another renderer for comparison
  5. Mantra - trying to match a Redshift render

    whole bunch of good hdr's here, free, no logging in or any crap either! http://hdrlabs.com/sibl/archive.html
  6. Mantra - trying to match a Redshift render

    Do you have a good HDR? And I do mean a very good one, I'm sure they had a very good one for theirs. Theirs looks more contrast-y than what you're using does, it could also be the source of that gradient. Their key light is also a lot brighter, not sure if that's in the hdr or not, but that would liven up your render, brighten up the ocean floor and put highlights on your subject, like in the other render What I did to find the best hdr for a particluar subject, is to take all the decent hdrs I had and make an image sequence out of them, then read the sequence into the environment dome / render the subject with a different hdr per frame - it's like doing 2 dozen test renders overnight - keep the hdr sequence for future use
  7. Help With Speeding Up Render

    Brutal scene! The refraction is the big killer, and the sizzling refuses to go away without really high settings - both separate issues, both contribute to the slow speed. I'm using Apprentice so I can only render at 1280x720, so my baseline to render your scene ( on an old 12-core ) is about 1 hour. What will help to reduce render times ( for this scene, not nec. all scenes ) is to use higher raytrace samples instead of higher pixel samples, to clean up noise. But you also need to set a lower Noise Level threshold ( under Min / Max Samples ) - your samples are nice and high, but the ( default ) high threshold stops mantra from using enough samples. 0.006 should be good, 0.003 would be cleaner but of course much slower. Then you should be able to reduce the pixel samples, so that areas with little or no noise, like the table and the liquid, will render many times faster. Using just 2 pixel samples, your table surface rendered clean & smooth, and really fast. Removing specular contribution from the lights, and adding grids with a white constant shader on them, parented to the lights, helps a lot but looks a bit different - you keep reflection but lose some spec highlights. That makes me wonder - why do you get any spec, with no roghness? I didn't see any roughness in any shader parameters - why would the reflections be noisy? Checked the shader - and even with Roughness set to 0.0, the reflections are still not sharp, and that's where your sizzling is coming from. I dove into the shader and found a Texture value at 1.0 connected to the roughness param, set it to 0.0, and the reflections got sharper, but still not completely sharp. But it should help this render quite a bit anyway, and I think this is where sidefx has to take over - Now I see that the reflections can be sharp, but only when there's no Transparency Adding transparency instantly introduces noise, via a wider cone angle, apprently. Stochastic off, or on with high samples makes little difference. Cranking up Reflection and Refraction Quality to 12 or higher helped, but that's slower of course - we really need to have the option of perfectly sharp reflections... a seperate param for refraction roughness would be nice too * still working on a final render, will post results soon
  8. Ok great, thanks - but I thought it was converting it anyway? Is there a tool to do the conversion beforehand? Googling - booyah! icp fixed everything, renders in 12sec now, thanks!
  9. Hi guys - In the Texture node ( with a mipmapped exr in it ) if I increase the Filter Width, any object reflecting the texture renders much slower. I guess changing the Filter width is actually running a blur filter on the entire texture map, instead of using a smaller tile - ? Is there any way to force it to trace just a lower-res tile? Thanks! Toby
  10. Somer renders to illustrate - the ground is a chrome shader, the background is a dome ( geo ) with the texture on it. Filtering @ 1.0, render time is 14 sec. Filtering @ 40.0, render time is 5 times longer ( when it should be faster ) 66 sec.
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