Fstorm render

[joconnell]

i think the lighting and camera settings are very minimal worries though, biggest thing that seem to bring realism is the models themselves and material because in real life there is sometimes terrible lighting and when you use a camera you can change the lighting as you like with a professional camera but the object and things around will stil look realistic now matter what

Just as a note, your camera does the same thing as fstorm does - when you take a photograph it shoots a flat, accurate, linear image, kind of like what vray is doing, it THEN puts some curves / tone mapping on it to make it look more like what shooting on film was like before it displays the image. Your camera isn't actually showing you what was in front of the lens, it's taking what was there and putting a bit of a style or look on it before displaying the picture to you.

[mitviz]

Just as a note, your camera does the same thing as fstorm does - when you take a photograph it shoots a flat, accurate, linear image, kind of like what vray is doing, it THEN puts some curves / tone mapping on it to make it look more like what shooting on film was like before it displays the image. Your camera isn't actually showing you what was in front of the lens, it's taking what was there and putting a bit of a style or look on it before displaying the picture to you.

i think its why the gpu guys are drawn to it and why i need to upgrade my gpu to start using it more

[Sbrusse]

I don't understand what all the hype is about tonemapping and LUTs and glare

Yes it's nice to have them in FStorm right out the box but you can do partially already that in Vray.
Vray has Reinhard (and others) in the VFB and in the renderer out of the box and support LUTs in the VFB. Lele released a LUTs switcher in real-time that is awesome by the way (Thanks mate I was looking for exactly that but integrated in the VFB since LUTs have been supported in the VFB)
Yes Glare and glow are better in FStorm and I like to do all my shopping in the same supper market (VFB) in stead of being obliged to go through various post production software.
But for me, all this thread should really about the actual calculation under the hood.

The initial thread spoke about FStorm rendering more "photoreal" than Vray. Sorry Vlado if that's a miss used term.
Saying they do the exact same thing per pixel is not true, maybe with while overlayed mtl on the whole scene as Lele and Tomasz like to point it out, but for me, we can't just stop there, a production rendered image is more than chalk renders to average noise based on sub-pixel cropped images.
I did two quick video here (had to cut in between because I was on the phone sorry about that)

Basically I opened my 3dsky account, downloaded the last scene in my purchased list, so it's not like I really search for anything special, just a average scene file we could all need on a daily base.

Part 01 :
https://drive.google.com/open?id=0B6...ENNTVZQaWotWW8

Part 02 :
https://drive.google.com/open?id=0B6...ktLdTFNMHRLT00

The 3 files as erx :
https://drive.google.com/open?id=0B6...Ghod2hPR3hpSGc
https://drive.google.com/open?id=0B6...U01aUs5NTBWQ1k
https://drive.google.com/open?id=0B6...nNsMVBuNnRzNzA

I tried to give a few impressions during the recording, but overall, and I can't say what is "physically correct" (and I'm sure Vlado you are way waay more accurate than I'm on that matter than I'm) but I can only say that in my humble opinion, FStrom looks better visually speaking, even in linear mode with tone-mapping/glare/bloom/DOF/MB/LUTs/whatever disabled.

Attaching the two final linear shots as jpeg for those who want to skip straight to the comparison.
Vray :


FStorm (linear) :


Vray Adv : (30 sec on my 3930k default settings) :


Fstrom has a clear issue with the tinted liquids as RT GPU and Adv are clearly close to each other. Not sure if it's not the conversion that failed.

Don't take me wrong, I love Vray RT GPU, I just hope Vray RT GPU will get the visual appealing look of FStorm (or more "photo-real" explanation word we can put on that) because I much ratter work in Vray than FStorm.

All this is really only focusing on the visual pixel to pixel comparison, for me there are some other strong points in favor of FStrom that improve the daily workflow :
* dynamic re-scale of render size without restarting RT
* dynamically disable cards in RT. (perfect to manage render/display cards and when you want to go "all in" or work smoothly in max)
* if a card fails to render, FStrom automatically re-start the render on that card or disable (IE the scene is too big for the GPU to handle) Once you start a RT session, it's pretty rare to have to re-start RT, relead Geo yes if you're still in modeling stage)
* bump works better in FStorm while creating mtl IMO

Hope this helps and explains why I don't get why every-one state that FStorm has a internal LUT that makes everything awesome, it's so much more IMHO.

[Sbrusse]

Ok I just figured out that Fstorm flips horizontally the HDRI compared to Vray, so here is another scene I quickly compared, now more I look at it in linear there is actually not much difference between Vray and FStorm

The main obvious difference seems to be the glass (maybe wrong conversion not sure) but also the way light propagates and hits the surfaces.
Mainly noticeable on the pepper on the left and how the light hits the table in front of the painting, seems like the sunlight hits more acutely the timber drawer.

The bump on the left white art is also quite noticeable (but we already mentioned bump before)

Another one is the textures colors, either FStorm saturates them out of the box or Vray desatures them, not sure but it looks better in FStorm (Again I don't know who is physically correct or wrong)

[joconnell]

Yep - there's some workflow and tool advantages in fstorm that people might prefer the feel of, and then theres the look / photorealism aspect of it. The look we can boil down to some tone mapping similar to what a camera does to mimic a filmic response and possibly some better glow / glare stuff - as you've found if you don't use any of that and make fstorm render linearly then you're going to have a very similar look to vray. All the renderers calculate GI using the same physics and anything that does realistic energy conservation on the materials is going to look very similar also.

Great if the discussion on the thread can be distilled down to the actionable notes for the chaos folks. More abstract notes like "it looks more photorealistic" can't really be converted into things that can be added to vray but if it's something like better tonemapping or the workflow features that you'd mentioned above then they're useful starting points

[wyszolmirski]

Ok I just figured out that Fstorm flips horizontally the HDRI compared to Vray, so here is another scene I quickly compared, now more I look at it in linear there is actually not much difference between Vray and FStorm

The main obvious difference seems to be the glass (maybe wrong conversion not sure) but also the way light propagates and hits the surfaces.
Mainly noticeable on the pepper on the left and how the light hits the table in front of the painting, seems like the sunlight hits more acutely the timber drawer.

The bump on the left white art is also quite noticeable (but we already mentioned bump before)

Another one is the textures colors, either FStorm saturates them out of the box or Vray desatures them, not sure but it looks better in FStorm (Again I don't know who is physically correct or wrong)

[ATTACH=CONFIG]31697[/ATTACH][ATTACH=CONFIG]31698[/ATTACH]

Cool tests. Could V-Ray have reflect on backside turned off ? This usually makes glass look bad. Other than that it's very close.

You have some solid points about FStorm as well in the last post. There is usually other side to things that has to be taken into account. Like it's cool it scales the render when resolution is changing, but bad that frame buffer is kept in video memory. When you render 10k or 2k in RT it doesn't affect memory usage on GPU.
RT shouldn't require you to restart 3ds max if you don't use in-process RT, there is probably some polishment still needed as sometimes it does in fact crash, but luckly much less with time. Please report everything to Chaosgroup to make live easier to all the users, they do really fix those little crashes and bugs
Bump in Fstorm looks solid, a bit easier to control out of the box, in RT VRayColor2Bump has to be used to get the same effect, but when I tested FStorm I couldn't find any way to use Normal Maps, that I find overall better at storing more information in 8bit formats.
One thing that I found that FStorm did better was denoising with many lights, while with 1-3 it was slower than RT, with several it was faster. But I guess it's matter of time and RT will improve at that as well.

Best,
Tomasz

[Moriah]

Fstorm developer said he doesn't have any plans to implement normal mapping... I think it's a huge mistake to do that...

[wyszolmirski]

Fstorm developer said he doesn't have any plans to implement normal mapping... I think it's a huge mistake to do that...

I second that. I love normal maps from Substance, they look so good and I use them very often.

[dlparisi]

One thing I've noticed in comparing the images is that Fstorm has a tendency to produce additional specular highlights compared to v-ray given identical lighting conditions. The second image set below seems to be getting a highlight off a highlight from the vase below rather than a light source. Fstorm left, Vray right...

Why is this? Is it simply a reflection depth issue or something else going on? BRDF differences? I don't think it makes the images any more photorealistic but it's something I've noticed on more than just the two images above.

FYI: you can also see the extra speculars in this set of images....http://forums.chaosgroup.com/showthr...271#post701271

[wyszolmirski]

In the one on the left I think it may be mix of depth and and reflect on back side option for the shader. On the right probably depth.

FStorm has depth at 8 by default, RT at 5.

[Moriah]

So apparently FStorm developer has been accused of copyright infringement by OTOY (Octane) claiming he used octane's source code to develop FStorm... Don't know what will happen with Fstorm now but one thing is for sure (from fb comments) - "OTOY is faster at filling lawsuits than they are at fixing their software."

[leo.surrealismo]

octane just filled a lawsuit again fstorm renderer for copyright infringement.

[dlparisi]

In the one on the left I think it may be mix of depth and and reflect on back side option for the shader. On the right probably depth.

FStorm has depth at 8 by default, RT at 5.

I'm not sure either is the reason actually (maybe the double highlight in the first image). If you look at the images on page 5 (the link at the end of my post) those were done with th regular adv renderer with the ray depth matched in each case and reflect on back side on for vray. In those you still see clear doubling of some of the highlights. Again, I'm not sure which is correct - the double highlights may be incorrect.

[glorybound]

Oops! There goes FStorm

So apparently FStorm developer has been accused of copyright infringement by OTOY (Octane) claiming he used octane's source code to develop FStorm... Don't know what will happen with Fstorm now but one thing is for sure (from fb comments) - "OTOY is faster at filling lawsuits than they are at fixing their software."

[mitviz]

Hopefully they make it in court, its nice software to use.