Kitchen...again...I hope it never gets old. :)

Become a member of the CGSociety

Connect, Share, and Learn with our Large Growing CG Art Community. It's Free!

Thread Tools Search this Thread Display Modes
Old 05 May 2013   #16
Regarding image-posting, I just use an external host (ImageShack) and link the images in. Here's an example of the lighting setup I was talking about, as well as the linking method:

Commodore 64 @ 1MHz
1541 Floppy Drive

"Like stone we battle the wind... Beat down and strangle the rains..."
Old 05 May 2013   #17
Hey, that's funny I was using this picture as a my motivation. I wanted to get close to it's look. I tried your method, and by the way thank you again for really taking your time for writing it. Maybe, it didn't took you long doing so, because you know the method by heart, but I appreciate the effort to give a clear answer. And I hope you'll get enough back out of all your contribution to CGSociety.

Back to the topic, I tried your method and I get something good. It came out a little too dark. As I'm not that familiar with area lights and portal lights, I dont know which settings I need to change to make the area light or physical sunlight stronger. I tried increasing intensity which didn't do anything. As this is a different technique, I don't believe that intensity has much to do with it. Also the physical sky gives a blueish look to the overall image.

I'll familiarize myself with area lights and portal light and see what I can find out by myself or the internet. And I'll upload a new render during the day.
Old 05 May 2013   #18
Sure, it's not a lighting technique which is terribly easy or will "happen overnight", there's no magic to mental ray, only study and lots of testing. My initial guess if your scene is too dark is that you're not using real-world measurements, possibly. You really want your units to = 1 for quadratic falloff to look proper in mental ray, and all your non-sun/sky lights should be using quadratic falloff.

For example, I model my scenes in inches/feet (silly Americans) in my CAD program, Rhino. Thus, when I import the scene as an .obj file into Maya as a "group", I then set the transform pivot to 0,0,0 on the grid and then rescale the entire group by.394 to convert inches to centimeters. For a long time I didn't know to do this, so I was constantly trying to increase my lights' intensity to compensate, but once your unity = 1 in mental ray, lighting becomes much more intuitive and there's a lot less guesswork.

Sorry to ramble on or overload you with information, perhaps it will be useful at some point!
Commodore 64 @ 1MHz
1541 Floppy Drive

"Like stone we battle the wind... Beat down and strangle the rains..."
Old 05 May 2013   #19
So here is my latest render. I took 1 hour to render.

I rescaled it. I'm working in meters. The kitchen is 6 meters large. My model was at 12 m, so I scaled it to half the size.

The portal lights have intensity multiplier set to 30. I had it at 50 but then the frame of the window was blown out. It still is quite white. And the scene is still a little bit dark.

InfernalDarkness, is your kitchen more lit, because there are more windows?

My light sources are only 2 area lights and physical sun
What I like about this method is that the reflections of the kitchen worktop and the specular of the floor work are way more present.

There are books missing on the right shelf, because the camera angle changed a little.
And the bottles are doing something weird to. I have to check their material.

Old 05 May 2013   #20
I think it's looking much better, much more natural and the indirect light is working way better too! It seems like a lot of your textures/shaders could use some work, but there's plenty of time for that later as well.

You're working with a 12m scene, so that's 1200cm obviously. If your scene scale was initially 12 meters, you should actually be dividing it down by 100, not by half. This may seem counter-intuitive at first, but for mental ray's lights to work properly, you want quadratic falloff (realistic falloff according to the inverse-square law) to appear properly. This is why your scene still seems pretty dark; you shouldn't have to increase the intensity of the portal lights at all really, except for artistic or compositional reasons. It should look pretty natural at an intensity of 1.

But it's looking good with the new lighting setup! Are all your materials mia_material_x in this scene, currently?
Commodore 64 @ 1MHz
1541 Floppy Drive

"Like stone we battle the wind... Beat down and strangle the rains..."
Old 05 May 2013   #21
Ok, now this explains alot. I'll scale everything down to cm.

Honestly, there is not one mia_material in the scene. Just basic maya shaders. And bump and specular maps. I have read about mia_material, but I haben't learned mental ray shaders yet.

I'm glad to hear that you like it, i like the new lighting too.
Old 05 May 2013   #22
Again, I hope we're not overloading you with information! But you can always bookmark or return to this thread later.

Every single shader in this scene should be a mia_material_x. There are multiple reasons for doing so:

1. mia_mat_x shaders are energy-conserving, and as a result will look more realistic and not as "blown out" or mislit. As long as you're using proper Linear lighting WorkFlow (LWF, generally), you'll get an accurate balance in your shader colorings. You cannot do this with Maya's native shaders.

2. mia_mat_x shaders usually render faster. With the "cutoff threshhold" for reflections and refractions, among other optimizations inside mental ray, you'll get a better result faster. You can also tweak their Indirect Illumination on a per-shader level, so that shaders which need more accuracy from FG can call it directly.

3. They have built-in, shader-based Ambient Occlusion. So you can use this on the shaders that need it, and it won't waste rendertime on shaders that don't.

4. You have control over your BRDF curves, but almost all materials in real life are Fresnel, in fact.

5. REAL reflections! None of the Maya-native shaders have real reflections of light involved, they all use "specularity", which is a fake reflection workaround to give infinitely-small non-Area Lights a "surface". With the mia_materials you don't need fake specularity at all, but if you do want to use this you still can. You control this in the Advanced section of the mia_material_x, "Specular Balance". 1 = fake specularity (Blinn/Phong style) and 0=real reflections only (all lights MUST be Area Lights for this to work, and they should be anyway). You can blend the two if you like, of course. I often run at .5 here.

6. You can plug in other excellent shaders such as the mia_light_surface, or use the Cutout Opacity slot for alpha-channeled shaders such as leaves, etc., which is entirely separate from the Transparency slots. The Maya native shaders cannot do any of this.

....and many other reasons!

But to get you up to speed quickly, here's a breakdown of how I make my mia_mat_x shaders:

1. Make your Maya-native shader exactly how you already are. Plug in the textures, etc. Don't spend too much time worrying about how they render though- you just want them to look proper in your Viewport.

2. In the Attribute Editor of your Blinn/Phong shader, click the Output Connections button (square with the arrow pointing right just to the right of the name box) to go to the Shading Group. You can of course go there directly in Hypershade.

3. Scroll down to the "mental ray" section of your Shading Group, roll it out, unroll the Contour Shaders and you should see "Custom Shaders". Here is where you create and insert your mia_material_x shader, and check "Suppress all Maya shaders". You use the same shader for Material, Shadow, and Photon slots, like this:

4. Now you simply plug in the file textures from your Blinn/Phong into the proper slots in your mia_material_x! Of course you'll be learning a new shader, and tweaking it a lot, but follow the presets as a guide or ask around, or check out one of the many online shader library utilities such as ShaderMonger or FBI Shader Library, or others for ideas and help, or to download new shaders directly. I use ShaderMonger, myself.

So this way, you still only have one texture file for each shader, so updating that file will update both shaders. Of course you may be using bump, reflection, or other files too - those can also connect to both the Blinn and the mia_mat_x simultaneously. This way, if you want to test your Blinn against the mia_mat_x, it's a snap. Or if you need to use Maya software for any reason, your Blinn is still fully intact and usable.

Hope this helps, it may seem obnoxious at first but if you want realistic results, you've gotta be using realistic shaders!
Commodore 64 @ 1MHz
1541 Floppy Drive

"Like stone we battle the wind... Beat down and strangle the rains..."
Old 05 May 2013   #23
No, this information is very interesting. Thank you. I'm soaking it up like a sponge.

Already the fact that this helps cutting down render time is great. Currently I am around 1 hour of rendering.

Unfortunately, I'm leaving for a small trekking this weekend, I'll be gone till next tuesday.
So I'll won't be able to do much till then. I'll try the mia_material_x as soon as I can.
It sounds great.
Old 06 June 2013   #24
Some new images.

They are a bit overlid.
Old 06 June 2013   #25
Vast improvement, there! Much more natural lighting, and the shaders are looking more realistic as well.
Commodore 64 @ 1MHz
1541 Floppy Drive

"Like stone we battle the wind... Beat down and strangle the rains..."
Old 06 June 2013   #26
Thank you Infernal Darkness,
it definitely looks better. I still see a lot of things that needs improving.
There is no glass geometry in the window at the moment, so no refraction.
Also I want to add a mounting with a metallic material into the wooden frame of the window.
So that it looks as an internal frame for the glass geometry.

Also I should put some texture/labels on the different glass containers and the books on the shelf. And perhaps add more props to the shelf on the right. But for now I'm happy. I learned a lot and I'm gonna take a pause from this project. Right now I can't see the forest for the trees. I'm tired looking at it.

So i'm gonna concentrate on a new project and more tutorials in maya, and I'll come back to this, when I have learned some more productive techniques. For example like cutting down render times. Right now it takes about 50 minutes to render a 1080 HD. Also I have to get better at texturing. The texture maps could use some re-work.

Also I want to concentrate a little bit more on contributing to CGsociety. Maybe I can help a fellow here and there in the forums. But I made huge progress in regard to my first render that I posted.
Old 06 June 2013   #27
Sounds like a terribly long render time. I'm guessing your machine is quite old? I had the same problem for years, struggling with an old machine.
Old 06 June 2013   #28
It's a mac pro 3.1 2.8 ghz eight core. It's old but still a good work horse. I think its coming from my render settings. I believe I can bring the render time down.
Old 06 June 2013   #29
Quote: It's a mac pro 3.1 2.8 ghz eight core.

Well, that would explain the render times at least.

Joking, kinda! But a few things that will help, usually vastly:

1. Final Gather - Accuracy 100 is usually enough, Point Interpolation 10-25.
Point Density however is where you gain the most speed. At 1, that's full accuracy per pixel rendered. At .1, however, it's 1/10th as accurate but 10x faster in the Final Gather phase. You can use .1 for all your test rendering, and then crank it up when you're happy with everything else for your final renderings. .5 should give decent quality, too. Also, you should get a slight jump in render speed if you're using caustics, even if you don't need to see the caustic effects.

2. Window pane geometry - the actual glass geometry which is of course just inside your Portal Lights should be set to NOT cast or receive shadows, for a huge boost in render speed. Unless you are doing a shot that requires good, clean caustics, turn off the shadows for your glass. What's happening with shadows on is that every photon and FG point generated from your Portal Lights comes in as a secondary or tertiary "ray bounce", which takes a lot more math to calculate. Your entire scene is basically a 2nd or 3rd bounce, instead of a primary one.

There are many other ways to speed things up, these are the two easiest off the top of my head.
Commodore 64 @ 1MHz
1541 Floppy Drive

"Like stone we battle the wind... Beat down and strangle the rains..."
Old 06 June 2013   #30
What a huge boost, I am down 4x the render time. It takes about 15 min to render now.
I gett noise in some places, but I can fix that in photoshop.

Yeah, well I'm trying to keep my mac pro as long as I can. I got very attached to it.
What are you using? PC or Mac?

Thank you Infernal Darkness.
Thread Closed share thread

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Society of Digital Artists

Powered by vBulletin
Copyright 2000 - 2006,
Jelsoft Enterprises Ltd.
Minimize Ads
Forum Jump

All times are GMT. The time now is 11:25 PM.

Powered by vBulletin
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.