Proper Workflow?

[craiggorton]

I've been reading the tutorials, linear workflow threads, and the excellent Visualization PDF that Micha posted in the links thread, but I'm still a bit lost.

I never know whether my materials are incorrect or my lighting. From Gijs linear workflow (and other) tutorials, it looks like I should override all materials to set up the lighting first, then turn on materials. But should I use 200, 200, 200 for the override material? What am I looking for in the lighting set-up? If I painted everything white in the real world and set up lighting to take a photo, it would look really bright even though the lighting was correct. So how can I use an all-white scene to set up lighting?

Also, the first image in the linear workflow tutorial shows a very grainy white image and then discusses 2 methods for correcting it. But when I use the low IR visopt, it's not grainy anyway. I don't really know whether to adjust the QMC sampler, the IR map settings, or the QMC GI subdivs.

I like IR map + QMC because it seems to work fast and with default settings. But the Visualization paper and the linear workflow tutorial focus on different parts of the options completely!

Also, is linear work flow something I should really try to master, or is it over my head? I'm not a full-time renderer. I don't want to create textures for every diffuse color I might use. I don't mind gamma correcting bitmap textures to .455. But if I create renderings for the web and for print, does it matter? I'm not about to buy calibration software/hardware. I've found that some of the magazine's art staff don't even know what the difference b/w file size and resolution is, let alone gamma. Is linear workflow more than most people need, or will my renderings look better to everyone? I don't care about physically correct images, I just want them to look good! But it makes sense that materials in my scene should resemble the textures I create them from.

Thanks,
Craig

[magnatizerr]

Proper Workflow?

Craiggorton - I'm in the exactly the same position (and very confussed right now?! ) .

Also, with many people saying that the gamma correction problem will be corrected in the next release, I'm not sure if it's worth learning a process (and creating a whole set of gamma corrected diffuse colours)?! - I think I'll keep using my old method until then - may not though

[dalomar_cg]

Proper Workflow?

Two things to start off. First is that we are working towards having all of the Linear Workflow stuff implimented in a way where its works automatically with everything. In VfSU we have a checkbox to correct colors and Maps (except for HDR images as those don't need correction) and this should be in the upcoming VfR service release. Second is that Linear workflow it worth using whether your a die hard renderer or not. It can make lighting easier and improve the overall look of your render.

As far implimenting Linear Workflow here is a really quick synopsis of what needs to be done.

1. Correct all of your inputs - this would be maps and colors which all you would need to do is change the override value to .4545 (or 1/2.2 if your keeping track at home) in the texture editor. Unfortunately at this point you would have to do this for colors as well, which would require making a small image then mapping that for the color. This will be changed in the future.

2. Correct your output - within the color mapping rollout change Gamma to 2.2. It is possible to preview gamma correction by clicking on the Srgb button in the Framebuffer, however it is better to correct you image with the gamma value because it will change how VRay samples your image (this is the point Gjis is showingin in his tutorial).

These are the two cornerstones of Linear Workflow. Obviously this is a really quick overview, but if you do these two things working Linearly should begin to make more sense. Just as a suggestion it maybe helpful make a quick, simple sene and render it without changing things for linear workflow and with changes for linear workflow. That way you can see the results side by side and hopefully get a better grasp on the steps need for linear workflow.

[craiggorton]

Proper Workflow?

Thanks Dalomar.
Does that mean that I should use gamma correction mode of color mapping? The tutorial didn't make sense what I should do with the other settings within gamma color mapping (inverse, etc).

Also, what might be useful for magnetizerr and me would be: about how long before the service release? Is it not happening before VfSU? Or is it imminent? I think what you describe is simple enough for me to want to do, except for maybe the simple diffuse colors. I may just adjust those manually for now.

I'll give it a shot.

So- if I override my material texture bitmaps with .455, set the gamma to 2.2, then I should be able to set up a lighting scene with those materials that makes sense. Then I can use that to design new materials? See, what I always run into is I have a diffuse material that looks too dark. Do I make the diffuse color lighter or increase my light intensity. I never know which one is correct. But I suppose if I use textures to test it, that might lead me in the right direction.

With that in mind, any suggestion on what color I should use for the global override materials when setting up lighting. What color did Gijs use in his tutorial?

Thanks for the help- we're getting somewhere!

[dalomar_cg]

Proper Workflow?

The two places your going to have to concern yourself with for lwf is the override value within the texture editor (for correcting maps) and the Gamma Value within the Color Mapping rollout in Vray Options (for correcting the rendered image). I think your getting confused with the actual type of color mapping as opposed to just the gamma correction (explanation of color mapping here) I usually stick with either linear or reinhard and with those types the gamma value (underneith clamp output and sub pixel) is where you would adjust to 2.2.

As for colors at this point your best bet is to go to photoshop an make a small image (8x8 is fine) and just fill it with the desired color. Then map it and correct it the way you would a regular texture. I know this sucks, but in order to be sure that you input is what you want its how you have to go. In the future this will be corrected so you don't have to do this step.

Keep in mind that your materials should be a constant and the lighting itself should be what changes the appearance of a material. For instance you wouldn't want to brighten the color of a material in a dark scene because its to dark, its the lighting that needs to be adjusted. Another quick example... the color of your shirt is what it is. If your standing in a room with no light chances are it will appear black (unless have night vision ), but if your standing under the lights at fenway then your shirt will probably look brighter than it did in the room with no light. Its the lighting that changed not the shirt. Begining to make sense.

As far as the global override color you don't actually have to change from white. This is because adjusting for gamma mainly has an affect on the midtones of an image, not the extremes of the spectrum.

As for a VfR SR and VfSU b3 status. Joe's first concern is to get the SU beta 3 out and that should be pretty soon. After that the Rhino SR is next on the chopping block.

Anymore questions...just keep 'em comin'

[Micha_cg]

Proper Workflow?

Hi Craig,

the LWF is necessary, because textures and the color wheel are based on gamma 2.2. The light distributation of Vray is calculated with gamma 1 and for a right view at your screen you need gamma 2.2 again.
Default wrong workflow is:
input gamma 2.2 -> gamma 1 ->gamma 2.2

If you set all colors/textures at 1/2.2=0.45, than you bring the input at gamma 1. Now lighting calculation and colors/textures match. At the end, the result output must converted to gamma 2.2 only.
So far the background. I wonder me, that this workflow issu was overseen a so long time.
Corey and Joe, maybe it's possible to quick implement the gamma corrected workflow in the last official release. I understand, that all the changes and bug fixes for the next release need time, but I feel, many new users are disappointed to run in this workflow issu.

What we need is a gamma 2.2 correction of input maps/colors. This could be done invisible for the user, like Maxwell do it. I'm not sure how many users use other textures as gamma 2.2.
Also we need an input gamma independent from the output gamma. The color mapping options are a good place for it. For example I read somewhere, that Mac computer work with gamma 1.8. So, it's useful to render gamma 1.8 images for the Mac community. Also, a harder gamma can help to get a special look of the image.

Craig, set all textures at the texture dialog at 0.45 and use color mapping reinhard burn 0.8/multiplier 1 and set gamma 2.2. If you use colors, you can create texture patches or trial/error.

I like IR map + QMC because it seems to work fast and with default settings.

I think, you can decide you between slower&easy ala autopilot or fast&advanced like a race driver. The best physical correct engine is the Light cache (LC). I recommend it to use it for sec engine allways. Extra advantage: you get a fast preview of the whole scene within seconds. If you try to keep it easy use LC+QMC. If you need more speed, you use LC+IM. If you setup IM at high settings, you lost speed, but you can be faster than LC+QMC.
Every blury effect need a subdiv avlue. This value determinate, how many samples are used. Less samples -> more noise. You can set it for each material, but an other method help you to make it very easy - full adaptive mode. Here a screenshot of the option dialog:

So, you have a range from autopilot ala Maxwell to full manual control of anything.
You find anything to this topic at my main tutorial F. Please let me know, which part could be more detailed or what I should change. I would like, if this tutorial could be the beginners first choice.

[craiggorton]

Proper Workflow?

Thanks Micha & Dalomar- I'm going to try LWF on the next project.

Keep in mind that your materials should be a constant and the lighting itself should be what changes the appearance of a material.

I understand this, but what I've never gotten is how I choose say an orange diffuse color that matches my orange shirt. I choose an orange that looks good, but it renders brighter than I think it should. So, change the diffuse or the light? I think what I will try, if this makes sense, is to use a texture like wood, place it in a test scene and set up the lighting around that. Then use that lighting in my scenes. Make sense?

I think your getting confused with the actual type of color mapping as opposed to just the gamma correction

Yes, I was confused. I get it now. I'll test linear and Reinhard.

Micha,
I'll start using LC as secondary and I'll stick with IM for now. It would helpful I think if we all referred to our GI settings by primary abbreviation first plus secondary. So irradiance primary plus light cache secondary would be IM+LC.

If you try to keep it easy use LC+QMC. If you need more speed, you use LC+IM.

This means to mean you want to use LC as primary- that's not really what you mean though? Also, I've seen IM written as IR- to limit confusion can we call it only IM?

And your tutorial is good, but:

In GI mode, if the white is set at (0,0,0), too much diffuse light will be reflected and will cause an incorrect indirect lighting effect.

I think you mean (255,255,255).

Here's also where your notation is confusing- the headings are "LC and QMC " but LC is secondary. The next heading is "LC and IM", but LC is again secondary. ?
Do you really want to use the blend multiplier for the wood texture? Image 2 shows gamma not overridden? Okay- I now see there was an update. I think you should remove the old stuff. Interesting for me to read to understand what's going on, but a new user will be confused. They'll go through the tutorial and then find that they need to change things. Keep it simple (and short). My opinion.

Also, you suggest 0.8 as secondary multiplier, but it sounds like there is debate about that. Is it still what you like?

I'm not on my vray computer now, but I will download the new scene from the tutorial and try it out.

Thanks for all the help, guys. You'll turn me into a pro, I'm sure.

Craig

[Micha_cg]

Proper Workflow?

Thank you very much for the suggestions.

I'll start using LC as secondary and I'll stick with IM for now. It would helpful I think if we all referred to our GI settings by primary abbreviation first plus secondary. So irradiance primary plus light cache secondary would be IM+LC.

Good, the truth is, that the LC is calculated first, but I agree, that cause confusion. LC for sec GI allways. Fixed.

Do you really want to use the blend multiplier for the wood texture? Image 2 shows gamma not overridden? Okay- I now see there was an update. I think you should remove the old stuff. Interesting for me to read to understand what's going on, but a new user will be confused. They'll go through the tutorial and then find that they need to change things. Keep it simple (and short). My opinion.

The blend multiplier works since the last release like a simple multiplier without blend. The tutorial is updated now, it was an old workflow. I will remove the gamma stuff after the next SR, than a global option do it.

Also, you suggest 0.8 as secondary multiplier, but it sounds like there is debate about that. Is it still what you like?

My experience: it works fine so and I have not seen any bad effect. It's a better workflow as set each color and each texture with multiplier 0.8. The best way would be, a global multiplier would allow to multiply each texture and color with 0.8. I got no feedback this will be implemented with the next SR or not? But I have the feeling, nobody will see the difference in the rendering between the usage of a general color multiplier and the GI multiplier.
Most important is to avoid full bright colors. I would like, if it is set per default so that knowbody must think about it, if he don't like to think about this kind of stuff.

[dalomar_cg]

Proper Workflow?

In regards to the lighting/materials thing here's what I would suggest. Have your solid materials (maps or colors) and have the understanding that thats the general look that you are going for. Then go about lighting your scene correctly (I usually start with basic GI then add the lighting elements from most influential to the final look to least influential). Keep in mind that you want to watch for colors being burned, which is why its useful to use the pixel information read out. If at that point you feel the need to adjust colors or map intensities thats fine. The thing you must be aware of is trying to compensate for improper lighting by adjusting materials and vise versa. Its really easy to fake alot of things within rendering, but you want to make sure that things are consistent and not just a trick

[magnatizerr]

Proper Workflow?

Craig - Any chance you could let us know how you get on? - Like you, I feel I should me using LW but still a little confused - I supposed I should just dive in?! - (Unfortunately, I suppose that this would mean that all my previous renderings / scenes would need updating?! )

[Micha_cg]

Proper Workflow?

... (Unfortunately, I suppose that this would mean that all my previous renderings / scenes would need updating?! )

... and I my tutorials.

[craiggorton]

Proper Workflow?

Craig - Any chance you could let us know how you get on?

I'll keep you posted!