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DrScarlett last won the day on June 27 2019

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About DrScarlett

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    Cafe Ronin

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    20.057 Studio

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  1. Some more experimenting: I figured out the blotchiness comes from the IR primary, not from the LM secondary. I managed to get some nice LM settings that work, but figuring out how to smoothen out the IR over a large planar surface was beyond me. Anyone have any info or tuts I can follow on that? I think the key is in the detailed settings in the IR tab. Also I tried the QMC + LM. No significant speed increase over the 200 hour QMC+QMC render, and no significant quality difference. It clear that it is using QMC as a primary is what bites me here. However, it is the only primary GI method so far that managed to give me quality without artifacts. Again, learning how to optimize primary QMC settings could help me here. I currently have no budget for a third party renderer, unfortunately :( Finally, I did some lights-out renderings that are nice to look at and then switch to a lights on render.
  2. Here's IR+LM (not QMC+LM as Cerbera suggested, so even a lower method than that). The direct illumination on the letters is a bit washed out, less nice details in the illumination, and some blotchiness of the green light further out on the tiles. But sort of acceptable. In just over 6 hours, lol.
  3. Haha, I enjoyed reading that, mostly because I am well aware . Don't worry, this would not have been my course of action had I a client waiting in the background Also the less perfect GI methods seem to be paying off. I seem to be getting a very comparable result (if I ignore some of the finer points) for under 7 hours of rendering. I'll show it to you later and prove your point
  4. Well, I had a look, and I have seen there are ways to use compositing tags to set quality requirements (stochastic sampling ratio, record density ratio) to force improvements where you want them. But my initial low and medium test settings were such bad results that I abandoned those directions. If you have a suggestion on what settings to use, that would be awesome.
  5. OK. It's done. This version is made like this: Scene: Outer neon class tubes is are cylinders of 20 mm diameter, wrapped onto the letter shaped splines. On top of that they have a glass thickness of 2 mm. The material is a 90% transparent material with 1.25 refraction index and a reflectance channel. The inner neon light tubes are cylinders of 10 mm diameter, wrapped onto the letter shaped splines. The material only has a luminance channel. The blue is 240% brightness, the green 350%. In both, in the Illumination channel, the generate GI is cranked up to 2500% (strength only, saturation remains 100%). Th outer neon class tubes have a compositing tag that turns off the "seen by rays" and "seen by GI". If the "seen by rays" is not turned off, the illuminated surfaces of the inner neon light tubes are not seen (completely black) in the render. If the "seen by GI" is not turned off, the glass blocks the GI illumination of the inner neon tubes onto the rest of the scene, so the surrounding objects are not illuminated by the neon illumination material. I fixed the earlier issues I had with the reflections by properly balancing out the diffuse and specular reflectivity of the floor tile material. The letters themselves are a grey (no color) plastic material with a bit of surface bump noise. Lighting: There are a couple of stark red object driven area lights in the background to the left and right, kind of soft-box like. That is all the lighting in the scene. It would be interesting to see a render with the neon turned off Rendering: The rendered used is physical in default setting and has ambient occlusion in default setting. The Global illumination is QMC for both primary and secondary method, diffuse depth 3, samples set to "high", accuracy 90%, glass/mirror optimization at 91%. I experimented with the "polygon light' setting of the illumination material. I believe it can help you optimize render times if you only care about the quality and graininess of the surfaces directly illuminated by the material. You can use it to focus calculation rays on those surfaces and drop down the ray count of the rest of the scene and secondary hops. in my case I could not find a way to use it and still get the overall quality I wanted. And here is the result. Rendered at 4800 x 2700. Took 212 hours to render: Overall, the way the scene looks, I am happy with it. I will not try any further without new idea's or information. I am not so happy with the neon tubes themselves, especially when rendered up close. Due to the compositing tag needed on the glass, the glass is not lit directly by the illumination material running inside it, it is only reflecting light on the outside from other sources. The look this creates is not natural. Also caustic dispersion effects of the glass do not occur, but that is not so important. Studying close-up shots of neon lights, and testing both the area light and the GI methods mentioned in this thread in some detail, in the end, I am still struggling to produce realistic looking neon tubes. I hope you all enjoy this info or find it in some way useful. I would be happy about any additional tips, especially on improving the close up look of the tubes.
  6. Thank you for those kind words, Vizn. The clips are indeed a type of black plastic, same material as the neon tube 'hub caps' at their ends, actually. That's the way I wanted it to be, they are small details, but I wanted them to be clearly visible. I can get a bit finicky, if results are not perfect, or if solutions do not work in the way I would, hmmm, expect them to. The area lights definitely have some unexpected side effects, due to the way that feature is implemented. I have switched over to GI illumination textures and found settings and rendering settings that produce an acceptable result. Now just wait for another 7 days or so for me to share the method details and the rendered result with you Hang on, incoming.
  7. So now my next question. I will go back to trying to simulate the tubes with luminous textures and use GI to get them to render. Would anyone have any tips for the best GI render settings to use in order to get a crisp realistic result in the scene above? Is the polygon light toggle in the texture illumination tab useful to use? Do I need to use QMC to make optimal use of that?
  8. So here are the results from the cutting-the-area-lights-into-pieces method. I have cut each spline into 6-12 pieces, and then re-applied the the cylinder shapes with spline wraps to get continuous tubes in the shape of the letters. First result shows it solves the blotchy reflection problem, however, suddenly different sections of different lengths are giving off different amounts of light. I tried changing the amount of samples in each section - no change. I tried changing the visibility of each section - this only affects the brightness of the tube itself. Only the light intensity seems to have an effect on the reflection brightness of the lights. I ended up making some Xpresso that that controls number of samples, light intensity and light visibility for each section. After 4 or 5 tries I got it all balanced out. This result is pretty okay. However now I discovered a new problem. It is hard to see in the image but the shadows (specifically those of the little clips holding the tubes) go in strange directions. I think this is because in calculating the area shadows, the center of each section of tubing plays a role, or the location of where most of the 'fake light samples' (internal method for creating the object based area lights) are, determine the direction of the shadow casting. Bummer. Another imperfection to the method. EDIT: Here is a high-res version of it, where you can see the strange shadows much better. Also a pretty nice look otherwise. Physical render, no GI. Took 153 hours :(
  9. One thing I would like to clear up, maybe, above we were not talking about rendering noise when we were talking about the maximum amount of samples - this was specifically about an idiosyncrasy of area lights, where you get blotchy reflections and specular reflections based on a specific sample setting of the area light. I can't, unfortunately, bypass that by pushing more light into them. I will still have the blotches, just more bright blotches. Also this idea probably works best with GI, which is what I was trying to avoid due to my lack of rendering power. However, the idea is valid, it helps me getting a better, more photo realistic render of the neon lights. I will come back to it - it looks like I might not be able to avoid GI, I have met with a few more problems with cutting up the area lights into pieces. I will show you the results when I am done.
  10. Thank you Vizn, a few follow up questions if you don't mind. Thank you in advance for your time. yes indeed, you are right. I know about the difficulties of photographing neon. It is very hard to capture the right balance between the neon light itself and the lighting on the surrounding scene. That I can use the C4D camera to follow the same process hadn't occurred to me. I need to learn how first. I suppose I use the camera exposure settings to do this? If I add more light, how does that fix the lack of samples - I will still have blotches in my reflections and speculars because of the lack of samples, no? Yes the scene is more or less at true scale, though the letters are very big, around a meter high. That is the way I wanted it. The neon glass tubes are 2 cm diameter, the neon light (supposed gas) is 1 cm diameter. What exactly is the relevance of the scale?
  11. Hey again, I tried the GI way before I posted. The rendered results are way too, hmm, fluffy The luminance based light give little in the way of material reflections or specular reflection. Since they are based on GI, the solution might be to muck about with render settings In order to get a decent fall-off behavior of the neon light (fall-off is almost impossible to control), the luminance values need to be completely blown out, resulting in an over exposed neon tube. That in turn forces me to go to a rather complicated composite tag setup with different objects for glass, GI light, and visual representation of the neon gas. I suppose if I keep throwing render tests at it, I will get there in the end, but render times in my test file are already over the top andit will take me literally weeks. Neon scenes are fairly common, I suppose, so maybe you (or someone else) have some other tips or sources that can help me get there faster? Meanwhile I am working on an area light version where the neon tube area lights have been cut into sections, controlling the balance of the light emission and visibility of each section with some Xpresso. This gives me a higher sample density per length of neon tube. Complicated, but easier to manage for me than the GI way. I will post if I get something.
  12. Hey Cerbera, thank you. I am using swept geometry (actually spline wrapped cylinders turned editable), because the lights themselves need to be visible (as the neon gas emanating light) and have a certain thickness. They are inside wider glass tubes. I control their visibility with the visibility modifier. I tried the add grain option, but the graininess in the resulting render is terrible (also at a 1000 samples), I don't know how to improve that. I would prefer not to see any grain in the reflection. I'll focus on this for now and get back to the bump problem once I have this sussed. **EDIT: fixed the reflection bump issue, it was a legacy error from previous tile texture
  13. Hey Cafe-ers, I have been trying to get good looking and possibly more or less believable neon lights going. I tried both the area light approach as well as the luminance material approach. I like the area lights best because I can do it without GI, the result looks crisp, the falloff looks more natural, I get nice reflections and specular. Also i don't have to muck about with separate objects for GI and camera behavior with compositing tags and compensate for overexposed neon tubes. Regardless of this preference I am looking for tips to make good neon with vanilla r20. For now I wanna ask the following. The pic below is a straight physical render using area lights. I am starting to like the overall look. There are two issues: The area light reflections look blotchy (already at a 1000 samples, add grain completely pixelates the reflection). I need more samples in the area lights. Any way to go above a 1000 samples? The bump in the floor reflection is off, the bump channel seems to have shifted and I don't know why. Would anyone have any hints or tips on all of this?
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