• Wednesday , 24 May 2017

Blender Internal Dispersion and Caustics – Explained

Code Canyon

https://i.ytimg.com/vi/gIT1g_LMd3E/hqdefault.jpg



…using the official 2.58 release

source

3d Ocean

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30 Comments

  1. ReznovRulz
    May 19, 2017 at 04:58

    OMG THANK YOU THANK YOU THANK YOU. I've been trying to figure out how to do a normal ramp in the nodes for so long!

  2. MrRecorder1
    May 19, 2017 at 04:58

    Thanks for the idea on caustics!! That is great! I will recycle the principle for another effect!

  3. contmike
    May 19, 2017 at 04:58

    Holy shit! :O You did an awesome job there 😀 Thank you for this video.

  4. Kram1032
    May 19, 2017 at 04:58

    @NionsChannel
    …continued
    I'll try a comparison of max vs avg, both with 6 samples, for comparison.

    The only reason why I think that the purple sample is important as well, is because it does have the highest IoR while red has the lowest one, relative to usual materials…
    So the difference in the two red channels will be the biggest and thus hardly neglectable. More than six samples shouldn't be too necessary though.

  5. Kram1032
    May 19, 2017 at 04:58

    @NionsChannel
    I also thought about it some more…
    It would be overkill of freedom (not too much slower in case of calculation, though), but you'd actually need to multiply each channel seperately by some factor that determins the sensitivity to a certain frequency range for the given colour-channel. While the red channel does react to purple light, it doesn't do so as much as it does for red light.
    Maybe, changing the colour of the sample is enough for that, though…
    continued…

  6. masterxeon1001
    May 19, 2017 at 04:58

    Genius!

  7. Daniel Widmann
    May 19, 2017 at 04:58

    @Kram1032 I just thought about it once more: given enough samples, your approach is probably closer to realism. The thing is: lets say you get the value 1 for a color sample. If you make an average calculation, you only see the full occurence of that color, if the other samples for the color channel(s) also have the value 1. On the other hand: if you take the maximum and the samples are close to each other, you only see mixed colors and loose elementary colors.

  8. Daniel Widmann
    May 19, 2017 at 04:58

    @Kram1032 I thought about the additive approach as well, however I'm still not sure which one is more realistic. It'd be glad to see some of your results.

  9. Kram1032
    May 19, 2017 at 04:58

    @NionsChannel
    thanks for the help 🙂 That worked.
    I did a slightly different version of yours, though:
    First, I used six samples, adding one in the purple range, which you missed. Second, I assumed it to be more realistic if you add the different values together, rather than choosing the bigger one, so I did some adding and then renormalization (three samples per colour -> multiply by constant .333 grey) instead.

  10. Kram1032
    May 19, 2017 at 04:58

    @NionsChannel Ah, thanks, that's probably it 🙂
    I looked at that and it's deactivated by default. I'll immediatedely try it with set to Transparency Checked, Option=Raytraced 🙂

  11. masterxeon1001
    May 19, 2017 at 04:58

    And here I was wondering what you were up to. Awesome video!

  12. J. C. Peterson
    May 19, 2017 at 04:58

    awesome video!

  13. Jeff S
    May 19, 2017 at 04:58

    Amazing. I've been using the Material and Texture nodes a lot in the past month. It's an incredibly useful tool that most people overlook.

  14. Carl Sagan
    May 19, 2017 at 04:58

    Blender, sorry XD

  15. Carl Sagan
    May 19, 2017 at 04:58

    Brilliant! Nion, what inspired you to use blendor, or better yet, animate. I have never seen such passion and to be honest, i could use a little. ^_^

  16. jrkirby
    May 19, 2017 at 04:58

    Someone should write a script to do caustics in that manner.

  17. Piotr Arłukowicz
    May 19, 2017 at 04:58

    man, you're true God of Blender, RESPECT! 🙂 Thank you for such an outstanding, advanced tut, this is REALLY KICKING ASS AWESOME! Sorry for caps, but even it don't express my feelings enough. GREAT!

  18. MoolahNasreddin
    May 19, 2017 at 04:58

    You are the hackiest Blender hacker I've seen before, Nion! 🙂
    You ought to make a proposal to implement this tricky dispersion effect to BI as the material's feature. I'm not sure the same possible about caustics (which is really great btw and can be a real exit for every PC without a powerful GPU). Just the matter of render times and setups.

  19. Daniel Widmann
    May 19, 2017 at 04:58

    @Kram1032 There should be a "Render Pipeline Options" section in the material settings. Have you activated transparency there?

  20. Kram1032
    May 19, 2017 at 04:58

    Hmmm, this looks awesome.
    But when I try replicating this effect, my Nodes don't use the transparency at all :-/
    Any ideas what could go wrong?

    (The transparency setting is greyed out. I set all my samples to RayTraced transparency. The samples each would render fine, but when combining via nodes, no transparency is used. Specular dispersion on solids looks nice too, but :-/)

  21. BlenderDiplom
    May 19, 2017 at 04:58

    Wow very informative and full of good ideas!

  22. onjoFilms
    May 19, 2017 at 04:58

    Yes, pretty complex and very interesting. Thanks for sharing.

  23. Blender3DProjects
    May 19, 2017 at 04:58

    Have I said that your logo is fantastic before? It is really well designed. 🙂

  24. MartianStories
    May 19, 2017 at 04:58

    @MartianStories 😀 Well, she WAS a German girl, so…

  25. Daniel Widmann
    May 19, 2017 at 04:58

    @MartianStories Thanks a lot for your words!
    …and the last sentence really made my day ;D

  26. MartianStories
    May 19, 2017 at 04:58

    A fantastic tutorial that my highschool physics teacher would have approved of. Thanks for posting something so insightful, Nion. Exactly the sort of thing we need more of.
    You're ridiculously talented. I've shown friends a lot of your effects reels and clips, and everyone has been like "DAYUM! You should get HIM to help make your movie!" (My ex used to go to extremes to get me away from the computer and into her pants, and wasn't keen on explanations about the workload of other animators…)

  27. Diego Herrera
    May 19, 2017 at 04:58

    @jookur LMAO

  28. Daniel Widmann
    May 19, 2017 at 04:58

    @xLDH1109x A first post? I didn't know I was that popular^^

  29. Diego Herrera
    May 19, 2017 at 04:58

    second

  30. Diego Herrera
    May 19, 2017 at 04:58

    first

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