Smoke render options

[magilla]

I just got the latest nightly and the smoke density options are no longer where they used to be.

Are there any good tutorials that cover rendering smoke?

[magilla]

when Based On is set to Smoke the Simple Smoke Factor does nothing - why?

[Svetlin.Nikolov]

Simple smoke works only when based on is simple smoke Which options are you looking for and what look are you trying to get?

[magilla]

Well that makes sense but perhaps that field should be greyed out - or used as an overall multiplier - when set to Smoke.

The spinners for subdivision reduction, exit and skip shading have disappeared or moved.

I'm trying to get an understanding of what I need to tweak to change the nature of the smoke. The standard tutorial I have seen is create light>atmosphere shadows>click render - bloody useless. There are some more in-depth tutes that go on forever but are not specifically about rendering.

[magilla]

no idea what is going on here, this is when the mode is set to Geometry Atmosphere

[magilla]

catch 22: vray zdepth requires the rendering mode to be Geometry Atmosphere, but the smoke only shows up in the vray atmosphere pass if the mode is set to Atmosphere.

[Svetlin.Nikolov]

Yup, the smoke exit and skip opacity are hidden and only accessible through script now. They are optimization options, which are better always set to 0.001 and 0.999 and we never saw a scene that requires some other value.

The subdivision reduction is still there, but is now called light cache undersampling, and goes between 0 (no undersampling, slowest and with least noise) to 1 (max undersampling, fastest and very noisy).

In general, regulating the simple smoke factor will give you more or less opacity, while playing with the external light scatter boost will give or take away volume from the smoke. Personally, I like to use brighter smoke color and to set the external light boost to 0.7-0.8 (reducing the light propagation inside the smoke), so I will get brighter highlights at the smoke edge and darker far side, with more tones inbetween.

We'll have a look at the atmosphere pass, we have a lot of work to do on the render elements.

[magilla]

that is brilliant, thanks heaps for this info. I realise that most of this info can be gleaned from the manual but practical descriptions (and video/graphic examples of this) are invaluable.

I was also interested in how affecting the curve in Smoke mode changes the nature of the smoke. Sharp peaks near zero on X can give the appearance of 'thin' smoke, that sort of thing. If I can find the time I would like to make up a reference chart with easily loaded presets for this sort of thing. If any other users have done this already please share your findings.

[Svetlin.Nikolov]

Yup, there will be new videos on this, we just have to clean it up a little more Also, we are in the process of adding render presets, soon they will appear in the nightlies so they can undergo some refinement, and there we'll add a preset for cigarette smoke with a smoke diagram with peaks. If you also come up with a preset that looks good on a number of different simulations, we can add it as well or merge it with the ones we prepared.