[Fernando Tella]

And you also like it with dispersion, uh?

Rock and Roooooooll!

https://www.youtube.com/watch?v=gfLD-7bCtME



This should be the anthem of Maxwellers.

[Aniki]

As you can see on the top images, they both are at SL 25, BUT merged from coop.

I am currently rendering on a single machine to the max.. but at SL 20 currently no caustics on/in the sss volume..

[Mihai]

Aniki, could you please try this test but instead of using Sun, try replacing it with a small emitter. It could be a limitation with the Sun emitter in this case....

[Aniki]

Mihai, I did, its the second image on the first post. Besides some rough noise, which is scattered like fireflies across the whole volume, I don't see caustics clearing up, do you?

[eric nixon]

I remember a render, which i cant find now, I'm pretty sure tom did a volume caustics render, of a glass ball above a square cloud. That would render faster now using volumetrics rather than sss.

I don't know what sl he needed though, and I'm sure he wouldn't use any presets.... (hint; presets were made many years ago, dont touch them)

[Aniki]

Well, using volumetrics wouldn't result in the same effect than an sss volume I guess.

Regarding the milk preset, I believe it wouldn't look any different as of today, pretty simple, single layered mxm.

So it rather looks like the sun caustics shouldn't be used for physical correct renderings, can't tell yet if the emitter approach is significantly better..

[Fernando Tella]

You could increase sun radius to 10 for example. If caustics do show they'll do it faster (a bit blurred, though, but for testing purpouses it would be ok)

[Mihai]

Aniki, how far was that small emitter in your second render? If it's a really strong emitter very far away it will be less efficient then if you placed a smaller one close by and not millions of watts.

[eric nixon]

Regarding the milk preset, I believe it wouldn't look any different as of today, pretty simple, single layered mxm.

Yes your right, the milk mxm was a SLOW material since day one. It is still is a slow mxm - check under the hood its not such a simple mxm. It uses opposing colours for trans / scattering, which is SLOW to render, The mxm was made over five years ago based on old assumptions. The point is dont use the maxwell presets.. they are just a legacy item.

Anyhow, even with a quicker sss material this situation wont render quickly, and using a sun or emitter wont make any difference.

[Aniki]

Mihai, it was far away, but not as far as the sun;)

I setup a new instance to render with a closer, less powerfull light now as well.

Eric, are you suggesting to use a different milk shader then? How would it differ from the preset? In what way would it fix the issue with the caustics then?


to summarize, I am rendering 4 different setups now, and currently it doesn't look like any of them is solving the issue. (yet two arent on a sufficient SL to tell for sure).

1- inital sun caustics approach



2- inital light caustics approach (far away)



3- adapted sun radius to 10 as suggested by Fernando



4- adapted light radius/distance/strength as suggested by Mihai

[eric nixon]

Aniki, re. SSS the stronger the effect the slower to render. (a white substance will therefore be slow) Also roughness between 2 - 20 is quicker to get to higher sl's than roughness 0, so totally clear fluids are slower.

And using opposing colours will slow things down further as I said already... so yes you can make a lot quicker sss materials generally, and a milk type sss could still be 5x quicker than that particularly ancient preset...

Why not try and match a photo of this effect, maybe tomato juice in a tumbler, or something like that.

I'm not saying its going to work, but I have seen it working in a previous version of maxwell at least (Toms volumteric caustics render) < this might even be in the manual or website, cant see it on my HD.

[Aniki]

Updated my post before with the respective results, first is at SL 23, the others around SL 16-17.

Eric, its not about speed, I am completely fine for this test to take time, its about the natural/physical result I am missing here.

I already took photos of milky fluids and caustics, evenly spreading from the ground across the fluid surface as you would expect to happen.

You are free to set it up the way it would work properly, grab the scene here:

Code: Select all

http://www.uglykids.org/ref/Caustics.zip

I'll leave the renderings running for some time now to see if some magic happens.

cheers and thanks for your suggestions so far.

[Mihai]

And using opposing colours will slow things down further as I said already... so yes you can make a lot quicker sss materials generally, and a milk type sss could still be 5x quicker than that particularly ancient preset...

An expression comes to mind involving money and putting them somewhere....I don't know how you can make an accurate milk material without first of all using those opposing colors and even without them, making it 5x faster. Lets see this wonder milk.

[Hervé]

well for what it's worth... here with Maxwell physical Sun and the recommended milk sss setting (sort of.. )

SL 18

Milk.png

here the mxm
http://www.divshare.com/download/26056285-4cc

[Aniki]

well, thanks Hervé but this isn't what it should look like and probably the same approach Mihai was suggesting.