Fstorm render

[^Lele^]

I took a look at the PDF but I couldn't really make much out of it.

No kidding.

[Vizioen]

As suspected, it just comes down to the user. Took me 5 minutes. Bottom row is bokeh. Ofcourse your input (lens settings), distances, and power of your lights need to be physically correct.

[jacksc02]

Nice one Ashley.
I really like the vray lens effects. Simple to use once you know what you are doing.
What would be nice is the ability to save/load presets from the VFB for lens effects.

[mitviz]

can you guys use that in a real scene for example an interior and see? when i use it it seems to make everything too soft,

https://www.youtube.com/watch?v=mD3cnvWf2K4

[peteristrate]

Vray Glare and Bloom are doing great for me, as far as I tested them, although I admit I don't use them since they are sluggish and lack interactivity.
The only thing that needs implementing is real-time interactivity which is something that the developers have in mind anyway.

Being able to save those from VFB and import them into another post-production software of choice(just like you can export the otehr colour corrections from the VFB) is something welcome as well.

[Midiaeffects]

I don't know why so much talk about FStorm glare. I mean, it's nice and all, but Octane has a very similar effect, but WAAAY faster, it's totally interactive. Anyway, despite Vray's glare being able to produce high quality results similar to Corona, FStorm or Octane, one still have to fiddle a bit with the settings, and that's not straightforward nor intuitive. So much that many veteran Vray users here were impressed by other engines without even knowing they can achieve almost the same thing right now. That alone says a lot. So it can definitely be improved. Here's my suggestions for Vray Lens Effects:

-Always end rays softly: First and foremost Glare should never EVER have those harsh finish like this or this, independent of the size. Sometimes it can be tricky to get rid of it. Looks like glare in Vray uses an internal bitmap mask or something, as if there's dirt on the lens. Glare rays must always produce a smooth gradient. This alone would cut complains in half.
-Glare rays to always be straight: Sounds crazy but when changing size, glare rays often suffer strange distortions. They are especially apparent with low f-numbers.
-Control over spacing: I don't know how physically accurate it is, but sometimes it doesn't look too realistic for me. With high f-numbers it and big glare sizes it looks very bad. Lowering the f-number kinda solves it, but makes rays sharper and we can't blur them.
-Glare Blur: Adds a nice touch when used with sharp rays.
-Diffraction amount: Again, I don't know how physically accurate it is, but I often find the effect too extreme.
-Rename Bloom to Haze: Right now Bloom is a gaussian Blur blended on top. Looks more like a Haze to me. A real Bloom is what Glare does when we turn off Blades to make it circular. But...
-Bloom and Glare as one: Bloom should be derived automatically from Glare itself, with multipliers for size and power.
-Intensity mask turned on by default: Solves this kind of "problem". It's a common source of complain that Bloom makes everything too soft/foggy, when simply masking with a threshold of 1 fix it. What is crazy though, is that we have to re-render for the threshold to take effect because Vray needs to generate a render element. Why does it have to generate a pass anyway? It's a simple color threshold, it doesn't need a pass.
-Make it faster and realtime in RT view: Can VrayLensEffect be GPU accelerated? Octane glare speed is a great reference.

*Bug: Glare is not grabbing F-Number from Physical Camera in max 2017 and Vray 3.40.02 here.

A setup similar to Corona's version:


-Eugenio

[^Lele^]

I'm not so sure on a few of those points you made, while others are on the to-do list.
However, what's there is quite usable as it is, if perhaps less straightforward than one would like, before having read the documentation and for some specific control moving to simple post.

1) rays do not always end softly, nor do they always end inside the image (see pictures below. At least mine ain't cropped.).
2) The bending is lensing, and you can see both bending and breakup of the rays below (albeit aided by having more layers in between source and CCD than just the lens for my photo. Obstacle image comes to the aid there.).
3) It's as phisically accurate as the paper it was built upon, and the fringing obeys the f-Stops quite correctly. If you take a look at the dropdowns for the mode, you can render your image with glare and bloom channels, add your material/objectID ones, and do all the fiddling you please in post.
4) ?
5) It is accurate. Read above for post work on the results of the effects.
6) Bloom is a convolution through an airy disk, or in layman terms, a weighted blur. However, it's also a specific technical term, and Haze already refers to something else (f.e. heat haze, or air variable IoR, which we can render in volumeGrid).
7) A checkbox to link the two could be a possibility, but forcing the two to work together, is a nono in my book. I want to use Bloom to kill the non-Anti-aliasable edges of my lights, but i'm no believer in Bayism, so won't turn on glare in a million years. They are also produced by two different, albeit similar, optical effects: suffice to say Glare is angle dependent, while bloom practically isn't.
Those controls do not work yet. On the to-do list. For now, all the control you want is three render element and a photoshop session away. Not in camera, but hardly a show-stopper.
9) *I* wouldn't know, so i won't answer.


A picture i took and The top crop of the wikipedia reference image for Glare:

[vlado]

I don't know why so much talk about FStorm glare. I mean, it's nice and all, but Octane has a very similar effect, but WAAAY faster, it's totally interactive. Anyway, despite Vray's glare being able to produce high quality results similar to Corona, FStorm or Octane, one still have to fiddle a bit with the settings, and that's not straightforward nor intuitive. So much that many veteran Vray users here were impressed by other engines without even knowing they can achieve almost the same thing right now. That alone says a lot. So it can definitely be improved.

Well, the V-Ray glare is derived from the camera aperture properties (which is what causes the effect in real life). While this is more physically accurate, there is sometimes no obvious correlation between the input parameters and the output result (f.e. it's hard to explain the effect of the f-number parameter). This can probably be reworked to a more artist-friendly set of controls.

Always end rays softly

This could be done easily.

Bloom and Glare as one

I don't really agree with that; these effects are caused by completely different physical phenomena - bloom is due to information bleeding between pixels where as glare is due to camera optics. While it is possible to calculate both effects in one pass, their controls should be separate.

Intensity mask turned on by default

I don't really agree with that either; in a real camera, the boom/glare are not applied selectively at some parts of the image only; they are present everywhere. FStorm for example doesn't offer any control of that either. I understand the option might be useful from an artistic point of view, but if we are sticking to any sort of physical plausibility, intensity mask should be off by default.

Can VrayLensEffect be GPU accelerated?

Yes, and our GPU guys will look into that at some point.

Best regards,
Vlado

[Midiaeffects]

Hey, thanks for the explanations Lele and Vlado. Very interesting to know that Bloom and Glare are completely different phenomena. I really appreciate it because clearly I don't know the physical causes of Glare and Bloom, so my requests are from an artistic point of view.

But I have to say I still struggle to believe VrayLensEffect is so accurate. I mean, let's look at the following examples using it on the sun of a daylight system: (camera settings: F-Stop 16, Shutter: 1/300, ISO:100)

-Glare at default settings. F-Number is at 16 to match camera ("from render camera" is not working). Lele, in your references Glare IS smooth, not when clipped by image boundaries of course, but still they neither form a perfect, harsh circle like this. Also, there's kind of a dirt between rays, which is why I say looks like Vray uses an internal bitmap, changing and distorting it, the effect doesn't look procedural. At defaults, it doesn't look good.


-Increasing glare size makes it look worse IMO. The spacing and the boundaries are very ugly.


-Even with size at 100, we still see the boundaries. The effect is very blurry and the spacing becomes very exaggerated.


-The effect simply doesn't look pretty or realistic in any way with F-Stop at 16. In the end I have to forget everything and play around until it looked nicer:



For F-Stop at 16, which is quite normal for daylight, it's hard to believe Vray's Glare is correct. Can't find a reference remotely similar to that. Am I approaching this case wrong? How to do it?

[snivlem]

An excellent V-Ray Project

https://www.behance.net/gallery/4163...-Nieuwe-School

This has that Corona and Fstorm "look" again, all just in the contrast and post processing....

[Midiaeffects]

And just for comparison. An Octane and FStorm version:

-Octane default settings:


-Just changed Blur size a bit gives a rather nice effect:



-FStorm at default settings:


-Changed Size and Blur a bit:


Reference Photo:

[vlado]

For F-Stop at 16, which is quite normal for daylight, it's hard to believe Vray's Glare is correct. Can't find a reference remotely similar to that. Am I approaching this case wrong? How to do it?

Well, the V-Ray glare is based on a particular paper that described how to derive the glare from the camera parameters. It is entirely possible that either the paper is not accurate or we implemented it wrongly... In retrospect, it might have been more straightforward to just ditch all of that and go for a more artistic approach like Octane and FStorm - it is probably worth to experiment with that.

There is also a standalone tool for generating glare images that comes with V-Ray; you can find it in the start menu > programs > Chaos Group > V-Ray for 3ds Max > Tools > Filter generator tool.

Best regards,
Vlado

[vlado]

Here is some random screenshot of the filter generator. It's not very convenient that it's a separate tool and at some point we wanted to include it in the VFB itself.

Best regards,
Vlado

[vlado]

And a resulting render from the frame buffer...

Best regards,
Vlado

[Vizioen]

Admittedly, it took my a while to get right, but that's actually because I've never used the filter generator tool before, but I got a result that is quite similar to your reference image.



And these were some tests before your post. Without the lens effect generator tool;