How does one do the gamma correction in Poser 6?  Where does one look?

I don't see the anything under render setting to indicate gamma correction or maybe I am not looking in the right place...

Quote - How does one do the gamma correction in Poser 6?  Where does one look?

I don't see the anything under render setting to indicate gamma correction or maybe I am not looking in the right place...

There isn't any GC in Poser 6 or 7 - only Poser Pro has it built in.

The lens posted here is one way to get it in Poser 5 through 7. Go back to page one of this thread and search for "gamma". I posted a version of the lens material that will do a decent job of making the darker areas brighter. This is pretty easy to set up and requires no other changes to your scene. The downside is that it adds render time to have to use refraction and raytracing. The other is the results aren't quite as good because your incoming material (image maps and color in node parameters) have not been anti-gamma corrected first.

The other way to do it is more work but more accurate. You have to use extra nodes in every material - every one - to do the incoming anti-gamma and the outgoing gamma. I've posted about this a few times, but it's not really a great workflow if you have a lot of materials that need changing. It's no problem for me to do that, since I have tools to speed up the process such as matmatic and VSS. Also, I tend to replace every material anyway, even if I didn't make any of the props or figures I use.

Quote - I had a few blue lights and the shadows became redish.  So I'd almost need to make them white and then colorize things with the HSV filter you were talking about.  I haven't had too much time to go back and tweak things yet as I only did a quick render.  I also noticed what you said about a scene having too muc lights; when adding the filter to the last image I put in my gallery and not doing anything else, the difference was huge.

Hmm. That doesn't happen to me. Can you give some more info about what you're doing? What are your lights - type, position, color, intensity?

What is the shader setup on your lens?

I just did an experiment with a blue light and it came out fine. I'll show you in my next post.

The light is a single infinite light from the upper right with ray-traced shadows. The light color is RGB 153,153,255. The light intensity is 50%.

I'm showing two renders - on the left without the lens, on the right with the lens. The lens setup is that on page 1, with the HSV Saturation at 2.0 and the gamma correction factor also at 2.0.

The un-corrected image on the left is extremely dark (at least on my monitor). It should look like that. If the figure is well lit without the lens, you are using way too much light.

This render with a single light is so we can see the contribution of lighting from the blue light. Next I'll add a small amount of IBL for ambient lighting.

Again, left is without the lens, right is with the lens.

While there is a lot more red now (from the white IBL and natrual skin color) I don't see the extreme redness you showed.

Since his right shoulder is in shadow and only lit by the IBL, the colors on that part of the body are identical in the last two renders. Only the parts being lit by the infinite have changed.

The first one has a slider RGB of .25, .50, 1.0 and is at xRotation -30.
The second one has a slider RGB of .70, .80, 1.0 and is yRot 50.

I used a single white diffuse light on this one.

Quote - Finally, here is my lens set up.

If you unchecked  on the root node: Reflection_Lite_Mult, you should see an improvement. I stumbled upon that accidentally while doing mat work. 

Remember reading about it being no good or unhelpful .

Quote - And here's something I discovered accidentally when leaving value2 of the power node black.

I used a single white diffuse light on this one.

This is no mystery. If you'll recall from math, any non-zero number raised to the zero power is 1. That is

x ^^ 0 == 1 for all x != 0

Now if Value_2 is black, that is numerically 0. Voila - all white no matter the incoming color value.

I think I know what's happening. Are you using the DAZ skin shader that comes with V4? That shader was written by face_off and uses a technique for faking sub-surface scattering I published a couple years ago.

The shader adds some red to the skin in areas that are weakly lit. The amount of red is very small but is effectively already gamma corrected. What I mean by that is that the amount of red introduced is just enough to be visible in a render that is not gamma corrected. Typically in areas of shadow it is about 3 to 10% red. This doesn't seem like much and with normal rendering is barely visible, because of how values like that display on your monitor. A 3% red value shows on your monitor as a true brightness of .044%. A 10% red value displays a true brightness of .63% on your monitor. These are tiny increments and are just enough to give the sense of sub-surface scattering.

But when you gamma correct those values using a gamma of 2.2, they are restored to the actual brightness of 3 to 10% red. That is very bright red!

I'm afraid that this is one of those cases where failure to anti-gamma correct the incoming material is causing problems. That's why I suggested that if you are going to do GC with the lens, you can't go with the full 2.2 value. Any skin shader that is already taking into account the severely decreased amount of red that shows on monitors will result in way too much red.

The same business is happening on the eyewhite. I'm pretty sure there is SSS being applied there too.

I think that the best you can do with lens-based GC is to stay clear of the full 2.2 value - you have to compromise.

As an alternative, might I suggest that you scrap the lens approach, and try my VSS figure shaders? They are fully self-gamma correcting and do not require the lens to produce realistic lighting and shadows on human figures.

Of course, then your other items in the scene need to be modified to match. You want to use gamma-correcting shaders on everything. The lens approach is quick and dirty, but limiting. Gamma correcting shaders are much more powerful. I know its a lot of work to convert all your existing shaders to GC shaders, but that's the best approach for "pro" work.

Eventually, VSS will provide single-click solutions to turn most any existing shader into a GC shader.

Andy Feller recently posted this render using VSS. I think the realism is outstanding. (Nudity)

http://www.renderosity.com/mod/gallery/index.php?image_id=1791637

BastBlack did a cool portrait of a pale Bishy here:

http://www.renderosity.com/mod/gallery/index.php?image_id=1771653

I like this one by Honey_ZA:

http://www.renderosity.com/mod/gallery/index.php?image_id=1763329

If you want to see more, click this to search the gallery for VSS:

http://www.renderosity.com/mod/gallery/search.php?query=vss&section_id=&genre_id=&sort=post_date&use_age=yes&older_age=1&older_units=day&newer_age=&newer_units=day&username=

Bill, for most of the images I've played around with for the lens I've just added a character pose from my library.  So unless they turn off that shader, I'm going to have to guess that I am using it.

Very interesting, thankyou. Can see I've got some new games to try

Fantastic BB!!!
The first effect you post is great, is it hard to be done? can it be done using colors?
The general procedure is the one used to get the ghost effect, isn't it?

Well BB, this is interesting; I stumbled into this thread and 3 pages on, I'm actually learning something in Poser.

I can't wait to try it out now.

JB

Excellent shader,  Bill!

Heck, I'm trying to work out how to fix it so I can parent the "Lens" to any camera I choose lol.

Thanks BB, I'm getting great results with this. :)

Silke, that's a good idea! Parenting the "lens" to any camera. Gonna try that.

Chromatic Aberration, at your service.

Here is the shader setup. With 3 Refracts, it's a bit slow. You can probably get away with only two - use cyan (blue+green) instead of just green and delete the whole blue section.

Anyway, this works but doing filtered refrections for each channel, with different IOR on each.

The bottom right node controls the overall amount of aberration.

The focal length of the camera will affect how much aberration there is. I used a 20mm here, so I'm getting a lot of aberration. (It increases with the angle between the camera and the lens.) If you're using a longer focal length, the rays are more parallel. In such cases you will have to increase the control value.

The amount of aberration is zero in the middle and increases to maximum in the corners. I don't know if real cameras work that way or not.

If you click on both in a tabbed browser, you can flip-test between them pretty easily.

For this to work, your lens must be square and centered in front of your camera.

You must adjust the lens so it just fills the viewport of the camera.

Very interesting...

I also added a Bias node to delay the darkening a bit.

Then you can darken it even more.

wow that's really impressive Bagginsbill!..thanks a lot,I'll be hoping to have a play with this during the week.
it always blows me away seeing the stuff you can do in the material room.

good job!

Cheers
Stefan

Quote - The basic setup is very simple.

At this point you can render and your original scene should appear unchanged. You have a neutral lens. Save this in your library for future use as a starter.

Not certain exactlywhat i am doing wrong here.
Followed you instructions Step By Step.

My Material Room setup looks like yours.
When i render (PoserPro) all I get is a black scene.
 

You have to enable ray-tracing. The lens works by using a Refract node. You have to have one more bounce than you usually need because of it. If you were rendering a scene without ray-tracing, then you need to enable it and add at least one bounce.

Quote - You have to enable ray-tracing. The lens works by using a Refract node. You have to have one more bounce than you usually need because of it. If you were rendering a scene without ray-tracing, then you need to enable it and add at least one bounce.

Happy Holidays BB

Many Thanks, that did the trick.

DR

Very nice! I'm adding this to the Material Room Bookmarks thread.

I had an odd experience with the gamma correction setup. I had a scene with a reflective water surface. With the lens on, the reflection wasn't there, and you could see below the water plane. It might have had to do with an intersection between the lens and the water plane? Time to play around some more.

AnAardvark,

The lens works by using a Refract node. In Poser, Reflections and Refractions count as a ray-trace "bounce" and there is a limit to these. You control the limit. If you have the limit at 1, then the only raytrace is going to be through the lens - the next one, bouncing off the water won't happen.

So I will quote myself from 3 posts ago, only this time in big letters so you all pay attention.

You have to have one more bounce than you usually need because of it. If you were rendering a scene without ray-tracing, then you need to enable it and add at least one bounce.

I hope that helps. Show us your render! I love to see renders.

You are correct. I went back to my saved file and realized that I hadn't set it up for the final render. (Usually I do all the prelims with a single bounce.)

I have a question about lenses... is it possible to simulate a toon look with them so I can just use the lens to make a toon scene?

bkmk

Quote - I have a question about lenses... is it possible to simulate a toon look with them so I can just use the lens to make a toon scene?

Not really.

I haven't seen any mention of this in the thread so far, but I came across a side effect of using the Artistic Lens.

For the last day or so I've been banging my head against the wall trying to get Poser to output an image that puts the figure on a transparent background so that I can render the background separately and apply post-work to it (fake depth of field) and then composite the figure on top of the background. Normally, the render just has to be on a black background and if you export it as a TIF or PNG, the black is interpreted as a transparency and everything is fine. But when I use the Artistic Lens to apply gamma correction and an anti-gamma saturation boost, either the black level or the alpha channel is affected and the background stays black and the alpha channel is one big block the size of the whole image, so selecting just the figure to do a composite of both renders isn't possible.

It should have occured to me sooner what was happening, but this is the first time I've actually done anything with compositing renders and alpha channels, so I thought I was doing something else wrong.

So it would seem that I'm going to have to stick to using Poser Pro's gamma correction function and apply the saturation boost in Photoshop. Hopefully the final result is close to what the Artistic Lens is capable of.

As far as Poser is concerned, seeing the background through refraction is not at all the same thing as directly seeing the background. So those pixels are no longer considered transparent.

If you're going to composite in post, then you don't need the lens at all, do you. I mean, the point of the lens was to avoid postwork.  If you intend to do postwork, particularly compositing, then why bother with the lens? To do a proper job of compositing, you'd want to adjust levels and tone the render against the background. My preference would be to avoid postwork altogether, which means I always render with my background in place in 3D, on a one-sided square or on an environment sphere. If I were of a mind to, I could also render in a picture frame, or signature, or other things.

If you have Poser Pro, then using PPro GC is superior to the lens. When you enable PPro GC, it will also fix your incoming material. Which means you won't get washout, which means you won't need the saturation boost. I suggested using the lens for GC when you do not have Poser Pro and you have to GC in post.

Quote - If you're going to composite in post, then you don't need the lens at all, do you. I mean, the point of the lens was to avoid postwork.  If you intend to do postwork, particularly compositing, then why bother with the lens?

for dozens of reasons.  because it takes about 2 seconds to do background blur in post and ages to get grainy blur in Poser, and your render takes more than a day without it.  because no existing figure has joints that don't need a good amount of post. because you need to correct gross anatomical errors.  just putting any Vicky's arm above her head generally means you need severe post to deal with the huge gap that shouldn't be there between her arm and head because, somehow, her arms end up way too long and her elbow too high.  because dynamic cloth with raytraced shadows is often impossible to use without getting artifacts or having a completely unhelpful bias.   because most textures have awful pubic hair and a completely and painfully unrealistic pubic region, and some of us like to do nudes.  because the eyebrows don't match the hair color and the easiest fix is a few seconds of postwork. because you want to depict someone with naturally curly hair, and all the 3d curly hair is awful or in ringlets (both mesh and dynamic).  because you don't want to spend hours morphing to get your conforming clothes to not look inflated and unnatural.  because you don't want to spend hours morphing to get your dynamic clothes to have better wrinkles than Poser's cloth room can provide.  because you don't want to spend time morphing a tiny bit of poke through.  because you like the cloth sim you have and don't want to alter it or spend time morphing just to account for a tiny bit of poke through.

because professional photographers pretty much never put their stuff out without tons of postwork, so why should we?

i use GC materials all the time now, and i've never done less than 8 hours of postwork on my images with them.  and mostly much, much more.

Quote - > Quote - I have a question about lenses... is it possible to simulate a toon look with them so I can just use the lens to make a toon scene?

Not really.

Okay thanks for the reply...  I was hoping there was another way to do toon renders.

cobaltdream,

You seem to be arguing a point that I did not make. At least I think I didn't make it. The gist of your post seems to be why we need postwork, as though I argued against postwork. I never said you can skip postwork. I asked why you need the lens if you're going to postwork anyway.

right.  i use Poser 6, and assuming it works in 6, it would be a lot easier to use the lens than alter every single material in the scene (though not necessarily better results?).  all the reasons i gave for doing postwork don't change anything that you'd want to use the lens for.  including compositing, because you might want your color to be right but blur need the alpha channel to blur the background.