Blender Internal Dispersion and Caustics - Explained

...using the official 2.58 release

Category:

Science & Technology

Tags:

• Blender
• Internal
• Dispersion
• Caustics
• Tutorial
• Explained

[Kram1032]

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 :-/)

[NionsChannel]

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

[Kram1032]

@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.

[NionsChannel]

@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.

[NionsChannel]

@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.

[MartianStories]

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...)

[NionsChannel]

@MartianStories Thanks a lot for your words!

...and the last sentence really made my day ;D

[NionsChannel]

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

[JailbreakAG]

Wow It Looks Amazing can you Uploud the blend file please?

[contmike]

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

[LukasVideosify]

That is awesome but doesn't Yafaray support Caustics?

[Kram1032]

@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.

[Kram1032]

@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...

[masterxeon1001]

Genius!

[Kram1032]

@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 :)