List of some bugs/tips for better Vray.

[Jiri.Matys]

Hi,
I found few bugs/annoing things and have some tips for better V-Ray I want to share. Some of them I have in my mind for a long time. And of course I dont mean it bad way. I just love V-Ray and I think you too. There can be always improvements and maybe you will agree and like my tips.

Bloom and Glare
I like this effects and all the settings. Now we can change intensity mask without rerendering, which is great. But there is few things which can be better I think:

1. When both effects are enabled, glare affects bloom. I mean when set glare intensity high, bloom effect dissappear. Its pitty.
2. Glare effect has two effects actualy - it makes radial glow and makes star filter. Its nice, but I have always problem that glow has much more intensity then star so I set it up and star is barely visible. Its working when light has high intensity and its small. Any other situation is not so good. Is it possible to make it as two effects - Glare and Star or something whatever you call it?
3. When I have orange light source and apply effects, those effects has white color instead of some orange color. High intensity makes it white, but room is lit with orange color so its kinda weird.
4. Diffraction is great, but it will be even greater with one slider for color intensity done by this effects. So we can make this color gradient more or less visible.

VFB
Frame buffer is great but little bit old. I love all its features, color corrections are fantastic and use it all the time. But it has some really annoing things.

1. When flare effects and/or Denoising are enabled and IPR mode is used, after few passes those effects are applied and vfb automatically change to effectsResult. Its nice, better will be the option in vfb to turn this off sometimes. What I mean: do some render test and want to see how image looks with those effects. Its ok, then I changing some scene/material settings and now dont what this effects because it take some time to compute it and mainly denoising after few passes looks terrible and everybody have to change it to rgb to see something. So now only chance is go to vray settings and disable denoising and go to lens effects and disable them. But its so much clicking. Only one button in vfb to disable automatic update will be great. And its annoing to instantly clicking to rgb channel button too, its not a good workaround.
2. Boxes for lens effects/color corrections/history should be in one place/side and three named icons switching between them. Now its more complicated again - simple situation: click on color correction to change something, then click on lens effects. It show on other side, when render is to big, whole window will move, then click on history and again whole window blink and move and cant see all settings either. And then I have to click three times to close all this bars. Instead simple three icons - click one to see lens effects, then click to see color corrections (one bar change from lens effects to color corrections) and then click one more to close it if I want. Nothing blink, whole window stays at the same position, still see max in the background and VFB has still the same size, I think it will be much better.
3. Ability to change IPR settings, denoise settings, DR and maybe basic GI settings right in VFB. If you change UI to what I said previously, only one new icon to switch side bar, but with all this settings in one panel - something like color corrections. Hope I wrote it understandable.
4. Like to see opacity slider for LUT correction. I didnt use LUT because cant make effect softer. Its just look somehow, almost every time too intense.

IPR
Its fantastic feature! Only few tips and bug fixes.

1. When hit F10 for render settings, IPR restart rendering but no scene changes have been made.
2. When change Light Cache subdivs, IPR didnt restart automatically.
3. Changing exposure value in Environments and Effects tab [8] not force IPR to restart rendering. Need to do this manually.
4. Changes to color mapping settings in system not force IPR to restart rendering.
5. Sometimes when IPR is running - node material editor didnt refresh node previews. Only workaround I found is to shift+move some node to clone it. After that node previews work again. Little bit annoing.
6. Working fog and aerial perspective in IPR. I know, Vlado said it will be working in VRay 3.6, so only for complete list.

RT
Dont use it so much, so I found only two things.

1. Render with CPU with all color corrections in VFB set up. Then swith to RT, render and then back to CPU. And all VFB settings is gone and have to set up all color corrections again. Pretty annoing.
2. When I try to render with GPU, lots of time I got some error and render dont even start. Its terrible to every time write on forum where is a problem. Please do some list of all this problem so everybody can find it and read how to fix that without writing on forum.

System
Some other things.

1. I like automatic subdivs. I think its little bit old these days to set subdivs for all materials and other parameters manually. So I think Chaos Group should work on this feature to make it working in all situations and hide subdivs from all materials. Automatic is good and its much better for newbies.
2. Now there are some situations automatic subdivs not working as well as everybody want. Some samples: simple scene with few objects lit only by dome light. Dome light globaly has worst quality then the rest of the scene - materials, other lights. So in simple scene noise is much more visible and render settings has to be much higher then in another situation. I would love when dome light still has some quality settings even in automatic mode. Other situation is refractive materials which are noisier most of the time then rest of the scene. Like this thread: https://forums.chaosgroup.com/forum/...ple-refraction.
3. And noise is terrible when room is lit with small amount of light and camera is set to lighten the room - something like 2 EV. Dont understand why this happening but noise in shadows is terrible. But when set for example 6 EV and lighten the image not with camera settings but with VFB color corrections, its fine.
4. Noise once more - in fog. Discuss this with Vlado so he knows about this - when light is in fog, noise is pretty high close to light and takes a lot of time to clean that in progressive mode but rest of the image is clean pretty soon. In bucket mode sometimes its impossible to clean it with pretty high settings which is useless for rest of the image.
5. If image is saved, color corrections are baked, its great. But when VRay Raw Image File is used its saved without all corrections. It is a pity.
6. Clarify some things - like light portals. Should be used or not? Or which situation. When used BF is portals useless? When IR is used, portal is needed? Or its useless at all? Then delete them.
7. I think when you do some research and change some things to make better you should get rid of the old one. Like new Glossy Fresnel - is it better to use this feature? Is it more realistic? Yes, so why there is an option to turn this off? I understand old scenes to look the same, but it can be internal thing. Its confusing for new users but for old one too what exactly this feature do (I mean in scenes and real situations in visualizations, not in physics) and when to use it and when not. No video explain it. Yes, I saw a few pictures comparing this feature on and off, but that's a little if it's so important. And if its better in every situation, why one more option to confuse people.
8. Its there for a long time. But I think subsurface scattering right in VRay material could be simplier and more understandable with only few parameters. Sometimes I use it and looks great but I use it few times a year and every time I have to find out how to use it
9. Solve the problem with transparent objects with aerial perspective, if its possible.
10. What about intensity option for lights affecting fog?

Its just some tips and founded bugs I want to share. You can agree or disagree, no problem. I wrote it as a starting point to think about some things. I dont mean it badly of course, we all love VRay here.
Make a list of all this things, tests and write it down to some understandable (I hope) text take some time, so please avoid any hints or the like.

[Jiri.Matys]

So here is the full list. Vlado, what do you think? And what the rest think about all tips?
Thank you.

[thanulee]

One thing that bugs me is that when i use IPR i have to press f10 to lock the ipr viewport. This lock imo should be on VFB. Same as the button that locks IPR res is hidden in system tab cheers

[Jiri.Matys]

Test I made about a problem written in section System - point 3.

First bad picture - camera exposure set to 2 EV, no color correction is made in VFB. Good second picture - camera exposure is set to 8 EV and picture is lighten up with VFB color correction exposure settings. No other changes in scene, only camera exposure. No antialiasing settings, no subdivisions, nothing. Only camera exposure can do this bad lighting/shadows. Dont know if this is normal.