I've noticed that volumetrics have not been rendering the way I would expect them to. There does not seem to be a gradual falloff for the intensity of volumetrics. Here's what I mean.
[attachmentid=15271]
The volumetric stops instantly at the falloff distance and does not continue into a gradient. Is this what is supoose to happen?

The top one is a kelig and this one is a bulb. The bulb functions properly with falloffs, but the intensity does not seem to be correct by any means.
[attachmentid=15272]

Sun volumetrics (a strange idea to begin with) work fine. with the falloff, but do not cover the entire visible area like a fog. It just makes a cylinder of light. By the way, the intensity of that sun is 9000% because it would have been inivisble otherwise.
[attachmentid=15273]

Do you guys have the same results?

yes I get the same here. Volumetrics get pretty handicapped because of this in some situation. As far as I know, it been that way at least since V7.

A fix would be nice.

Aww. Though there is a way around it, and that would be to use a bulb light with volumetrics; however, if I needed to just add a simple effect in a light, I would be out of luck.

Hi Matt, if I use this setting, I got this:
[attachmentid=15288]

Is that klieg rotated on any other not parallel to the screen? And if it is not, did you render that with Multi-Pass? I'll try out the contrast adjustment to see if that does the trick.

Matt:

I did some work with underwater effects a while back and got better results when I played with the contrast settings of the Volumetrics. This render had the contrast up to 55%. All the red ticks are areas that I played with. I know it's not perfect, but it did the job for me.

Eric

The klieg was rotated on x axis only and viewed from left. I used 16x Multipass.

Simply drag your falloff region longer, Matt.

Okay, I ran five quick tests, and here is what I came up with: It is unnessisary and recommended not to adjust the falloff distance or intensity to adjust the fade of volumetrics; this will change how models are light which is not desired. he width of falloff adjusts the thickness of the end of the volumetric. The best choices to adjust the fade are brightness and contrast. T Here are the five tests.

Brightness Adjustments 0%-100%: [attachmentid=15311]
Constrast Adjustments 0%-100%: [attachmentid=15312]
Falloff Distance Adjustment 100cm-500cm: [attachmentid=15313]
Intensity Adjustments 0%-100%: [attachmentid=15314]
Width of Softness Adjustments 0%-100%: [attachmentid=15315]

These are all in the same light cone. Lengthen the cone, Matt.

Martin, I lengthened the cone. That is the falloff distance test.

Hmmmm... Put it in A:M Reports.

The cone length really shouldn't be changed. A scene that someone wants to put volumetrics in should be first set up for proper lighting, and second, the volumetrics should added and the brightness and contrast be adjusted for the volumetrics.

Unlike "real" light, CG light is supposed to be contained within that cone. This allows the lighter to more accurately position lights to prevent bleed. (A:M Forces work similarly.) If you want the volumetric to extend then the cone must extend. However, I haven't thought about this in years (10?), so maybe you have some valid suggestions?

p.s. You know you can drop a Turbulence on that light if you want swirling dust in the volumetric, don't you?

The only suggestion I have at the moment is to make an archlength fall off distance for volumetrics.

The only reason for getting the noticeable line at the end of the volumetrics is because the volumetrics all falloff at a rate that is parallel to the angle of the klieg (at least that's what I've observed). When the volumetrics near the fall off distance, they start to drop in brightness. Because the brightness drops at the same rate, the middle of the volumetric appears to be falling off at a slower rate, but that is only appearance. The middle is seen as being denser because the volumetric rays are additive to the other volumetric rays. To get the end of volumetric to properly fade, the fall off would have to be an arch length, not a planer measurement.

As strange as this may sound, there already is a fall off softness for volumetrics. It's writen in the help file; however, after searching high and low for it, I did not find it. Has anyone else seen anything like this? Perhaps it is just the version.

I can't. I put turbulence on a light - sure it was turbulent but it didn't animate & try as I might, I could not get it to swirl, animate, or move in any way.

So now I'm just using cone shaped volumetrice which would look great if I could get the thing to render!
frustrated Cat.

Make a copy of your light, turn volumetirics off on the original, and set "Light all models" to off on the copy. Now you can adjust the volumetrics on the second light without affecting the illumination of your scene.