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View Full Version : Why is there no Ambient Color slot in both Mental Ray & VRay??


custinyakis
11-03-2008, 02:42 PM
Maya does have Ambient Color Setting for its every material. It's great because with ambient color option I don't have to create & tweak hidden lights in my scenes for cartoony, colorful shading effects. Why doesn't Max have this feature?

captain brainiac
11-03-2008, 03:44 PM
It has, but not in the material editor... you can define one global ambient light value in the environment settings.

spacefrog
11-03-2008, 04:01 PM
captain brainiac:
you are wrong - every Standard Max Material has an "ambient color" but Vray & Mental ray materials do not. But since those are special Materials for their specific renderers and they target Realism, i think it would be counterproductive to have such horrible fake mechanisms in them. Both renderers support Standard Materials by the way, so use the standard materals if you cannot live without "ambient color" per material. Additionaly you have the "Ambient Color" Setting in the Environment" Settings which add even more control ambient light.

krembo99
11-03-2008, 04:14 PM
Why is there no Ambient Color slot in both Mental Ray & VRay??

Because they do not need it ! :rolleyes:

custinyakis
11-03-2008, 04:16 PM
Thanks for the reply guys. Yes every standard max material has its own ambient color. but they become active only when you make the ambient "white" in the Environment Settings.

The thing that I'm trying to say; VRay & Mental Ray is so limiting. Because what if I want a material with an ambient color + glossy reflections + glossy refractions ??

By the way I think a rendering engine should be flexible. It should able to create physically realistic visuals but also should let the user to bend them. I'm right now trying Splutterfish Brazil Learning Edition in Max & it has all the tools that I want.

krembo99
11-03-2008, 04:44 PM
//The thing that I'm trying to say; VRay & Mental Ray is so limiting. Because what if I want a material with an ambient color + glossy reflections + glossy refractions ??
You must be kidding, right ??:curious:

By the way I think a rendering engine should be flexible. It should able to create physically realistic visuals but also should let the user to bend them.

I do not think that there is a render engine more flexible than Vray ! and I am sure that most of the pros will agree on that... you can argue about a lot of things, but not about it's flexibility..

I'm right now trying Splutterfish Brazil Learning Edition in Max & it has all the tools that I want.
If that is so, so just keep on using it ..
It is very important to feel comfortable with the software you use, Like Bobo replied to another thread here :

So there is not reason to push yourself into using something you don't like - it will make you unhappy and unproductive, and our lifes miserable too as we would have to read your complaints on CGTalk ;)

(This quote should be in the site's header :-)

custinyakis
11-03-2008, 04:52 PM
sooo with all your aggressive stance would you please kindly answer me how can I create a material consists of a diffuse color + ambient color + glossy reflections + glossy refractions in VRay??
seems you know it all, please enlighten me :twisted:

krembo99
11-03-2008, 05:43 PM
First of all, I was not aggressive at all..
All my posts here at this forum are meant to either help other people, or to learn myself. (And you are welcome to go and check my posts)
Second , the "know-it-all" is an automatic Phrase that Cgtalk puts on a user with so-many posts (not sure exactly , but I think 300) and that never changed it to a custom writing of it's own. I did not write this myself.
And third : you mean materials like these ??

http://www.krembo99.com/wp/wp-content/uploads/support/photo/Cgtalk-forums/20081103.materials.vray.jpg

custinyakis
11-03-2008, 06:06 PM
http://img353.imageshack.us/img353/7949/5857698fn3.jpghttp://img219.imageshack.us/img219/9030/12334nu2.jpg

I'm sorry but at first glance it came a little aggressive to me. By the way I'm talking about these types of materials. Materials with no pitch black shadow sides. The first Image I rendered in Max with Brazil Rio & the second one is rendered in Maya/Mental Ray. It's so sad for me I cannot create materials like that in VRay & Max's Mental Ray.

captain brainiac
11-03-2008, 06:27 PM
captain brainiac:
you are wrong - every Standard Max Material has an "ambient color" but Vray & Mental ray materials do not.

Poop.... you are right... need to sleep more! :D
Sorry for the overmisconfusement!

krembo99
11-03-2008, 06:34 PM
I am sorry, It seems to me that I fail to understand what is special about the materials you posted ...

http://www.krembo99.com/wp/wp-content/uploads/support/photo/Cgtalk-forums/20081103.materials.2.vray.jpg

DevIII
11-03-2008, 06:47 PM
off hand both mental rays and vray (tho I've never used it) are gi renderers, so the ambient values are picked up from bounce light in the scene. a common example would be an out door render, inwhich things get slight blue tinting from the sky. if you were doing a similar effect in scanline you might use the ambiant value of the shader to control this. but theres really no need in mentalrays todo that, because of the gi calculations. you can use gi rendering for anything you want. I find myself using mental rays on nearly all of my finished projects now supper real or not. if you really want cartoony, mental rays has a very excelent tho technically driven cell shader, if thats your cup of tea.

it looks to me like you need to do the basic tutorials and learn how to setup the rendering engines to use them properly. there's a big difference between standard rendering and GI rendering, you should really clear you mind as you do these tutorials and you learn a great deal, alot goes into setting up a gi render, from proper camera settings to the colors in the environment, and the lights. it seems like Brazil just defaults with some settings that you like and thats what your basing your opinion off of. if you look at profession renders they don't have the problem your complaining about, that should be the first clue that you missed something.

custinyakis
11-03-2008, 06:48 PM
No problem. Actually it's hard to explain it without visual reference. I should have posted some renders in the first place. Is this a VRay render you've posted? By the way I think I'm gonna stick with Brazil for this type of effects. Thank you so much for your time though

custinyakis
11-03-2008, 06:51 PM
Thank you Devlll I'll definitely take your advice.

spacefrog
11-03-2008, 06:55 PM
It's so sad for me I cannot create materials like that in VRay & Max's Mental Ray.

it's possible - in this case lack of knowledge about the tools is the limiting factor...
Sure - it's a little to easier to complain about limiting renderers, but this not the case.

custinyakis
11-03-2008, 07:11 PM
before posting think about it a little & read my quote that you've pasted again space frog.

what does ''I cannot create..." mean?

let me tell you. it means "the rendering engine (VRay in this case) might be capaple of producing such an effect but I'm not able to resolve it.

& (in your words) the easiest part is to criticize the thoughts of the others without helping them.

Almir
11-03-2008, 07:59 PM
I'm sorry I don't understand why don't you blend whatever "physical" material you wish with a vraylight material, or glow shader in mental ray? or bake a light map for that matter?
~sion

krembo99
11-03-2008, 11:22 PM
Is this a VRay render you've posted?

Yes it is Vray, with the lowest posiable quality, 30 seconds of settings + 15 of rendering.

ctrl.studio
11-04-2008, 12:25 AM
guys, take care that the ambient component in a shading model is general just a multiplier.
you should separate the shading part from the reflect/refract component. multiply the shading part by a constant color and then add the reflect/refract to the whole.

http://img90.imageshack.us/img90/8274/archdesignambientci6.th.jpg (http://img90.imageshack.us/my.php?image=archdesignambientci6.jpg)http://img90.imageshack.us/images/thpix.gif (http://g.imageshack.us/thpix.php)

JeffPatton
11-04-2008, 02:16 AM
The thing that I'm trying to say; VRay & Mental Ray is so limiting. Because what if I want a material with an ambient color + glossy reflections + glossy refractions ??For mental ray, I don't see why you couldn't simply use the self-illumination or additional light options on the A&D material. Or I suppose you could also use some of the hidden shaders like the illumination blinn or illumination ward because some of the older mental ray shaders like those have an ambient color option. Although I'd recommend sticking with the A&D instead if you're needing glossy reflections/refractions in addition to the ambient color.

EDIT: Of course I'm assuming physical accuracy isn't of any concern here.

krembo99
11-04-2008, 05:51 AM
....And I did not wanted to point it out before, because I did not wanted this thread to be prolonged beyond it's reasonable limits, but one other option (for the second type) would also be the VrayFastSSS ...

custinyakis - I think it would be safe to say that if your goal is really to learn (and not arguing/fighting with people on forums :) ) than you have a long way to go.
Every person that is working with CG at a certain level, will tell you that in order to really do that "big leap" you need to study a LOT of theory as well.
Understanding (But really understanding) what people wrote here above takes a bit of studying. Knowing what is the difference between Blinn , Phong - or what is SSS , how a highlight is produced and what is frensel diffraction , all those things come with a lot of study (and practice).
For example, Knowing a bit of theory, you would know that using Ambient-color is not even a GI method (but a "cheat") because there is no Diffuse reflection or intereflection used.)
Just taking the "off-the-shelf" % "out of the box" settings from a render engine (or any other software for that matter) will not give you the right view of it's true potential. (After all - for someone who does not know how to fly, even an F-16 is a bad aircraft )
Some people here demonstrated to you how easy it is to achive what you thought was impossiable for you. And believe me, no one yet pulled the "Big Guns".
I want to believe that most people here on the forums have the goal to help and learn (I know I learned A LOT here). So use that fact smartly, and instead of grouch and lamantation (that leads to resentment and offense) , Just ask what you don't know, and I guarantee you will get the answer you are looking for.

krembo99
11-04-2008, 06:00 AM
guys, take care that the ambient component in a shading model is general just a multiplier.
you should separate the shading part from the reflect/refract component. multiply the shading part by a constant color and then add the reflect/refract to the whole.

http://img90.imageshack.us/images/thpix.gif (http://g.imageshack.us/thpix.php)

I am not a big expert on that , But I am not so sure of what you said..
I think it depends on the shader type.
As far as I know, in Phong for example, The intensity of the diffuse component varies with the direction of the surface, and the ambient component is uniform (independent of direction). So I do not know if just a simple multiplier will do.

custinyakis
11-04-2008, 09:48 AM
Thank you so much Jeff Patton & ctrl.studio. This what I've been looking for.

krembo99- I'm well aware of the principles of Indirect Illumination in VRay, Mental Ray,Brazil rendering engines & I'm using them quite frequently in my work. But here GI is not the concern. I was specially trying to achieve these kinds of non-physical effects. I think the problem is I was wrong when I was saying negative things about respected rendering engines such as VRay & Mental Ray in 3ds MAX. So sorry about that.
Now as I follow "the real information" from ctrl.sudio & JeffPatton's posts I will study harder to understand these renderers. Thank you again.

ctrl.studio
11-04-2008, 01:22 PM
I am not a big expert on that , But I am not so sure of what you said..
I think it depends on the shader type.
As far as I know, in Phong for example, The intensity of the diffuse component varies with the direction of the surface, and the ambient component is uniform (independent of direction). So I do not know if just a simple multiplier will do.Uh... if you ask me.. I'm pretty sure of what I said. :cool:

max

raymarcher
11-04-2008, 09:29 PM
hey ctrl.studio, will there ever be a decent ctrl.mix8layer for 3ds max? :bowdown: Then it would be easy to construct our own shaders.

krembo99
11-04-2008, 09:46 PM
Uh... if you ask me.. I'm pretty sure of what I said. :cool:


well, Like I said, I am not a big expert on that.
(Sicuramente ne capisci piu te..)

MasterZap
11-05-2008, 07:50 AM
"Ambient" light was a traditional hack to simulate bounce light and "omnipresent" lighting in a scene. A physically correct renderer normaly frowns upon such techniques; you should in general be using GI techniques.

However, in certain situations (stylistic renderings, or to be sure not to have any animation artifacts that may be caused by interpolation-tricks used by any (undersampling) GI technique) you may want to use traditional "ambient" light.

However, plain flat "ambient" looks horrible; it is far better to use ambient occlusion together with the ambient contribution.

A render using one shadow casting omni, plus using plain, flat, ambient light:
http://i51.photobucket.com/albums/f366/MasterZap/ambient-plain.jpg
This looks horrible and unrealisic.

However, a render applying occlusion to the ambient component looks as follows:
http://i51.photobucket.com/albums/f366/MasterZap/ambient-occluded.jpg
This is much more realistic.

Note that a COMMON ERROR is to render an "occlusion pass" and apply this globally across the image. This is WRONG. It will cause occlusion also in the directly lit area by shadow casting omni light, which would make the image look "dirty" and unrealistic in the other direction. Occlusion should be applied to "ambient" light only (that's why it's known as "Ambient Occlusion")


In mental ray, there are several ways to do this:

Method #1: Use the Arch&Design materials "Special Effects" rollout.





Open the material in the material editor
Go to the "Special Effects" rollout.
Turn on the "Ambient Occlusion" and
EITHER: put in a given ambient light color in the material...
...OR: switch to the "global" mode, which will use the "ambient" color and intensity from the Environment dialog box:
http://i51.photobucket.com/albums/f366/MasterZap/special-effects-rollout.jpg

This allows you either per-material or global ambient light levels, and you can easily modify the ambient occlusion radius from the special effects rollout.

Method #2: Use a light set to "Ambient".


- Create an Omni light
- In it's Advanced rollout, set the light to "Ambient Only"
http://i51.photobucket.com/albums/f366/MasterZap/ambient-only.jpg

The drawback of Method#2 is that you get no ambient occlusion effect in the ambient light. This can be fixed by adding the Ambient Occlusion shader as the "Projector Map" of the light. BUT. There is a big BUT: For this to work, you MUST have the light with it's transformation reset, i.e. it must be placed at 0,0,0 in the top viewport, or the ambient occlusion shader will be confused.

This can most easily be accomplished by running this short script:


myLight = Omnilight()
myLight.AmbientOnly = true
myLight.projectorMap = Ambient_Reflective_Occlusion__3dsmax()


Go to MaxScript menu, choose "New Script", paste the above snippet in and hit CTRL-E, you will have a set up light, where you can modify it's intensity and color etc. w. the normal 3ds max light features. The only thing you need to look out for is if you wan to set the distance for the ambient occlusion rays, you must

take the "Ambient/Reflective Occlusion" shader that is in the projector map
drag-and-drop it into the material editor
choose "Instance"
...and modify the settings from the material editor
(There is actually a Method#3 which involves using the Ambient/Reflective Occlusion shader as the light shader of the light, but it won't be delved into here)

/Z

raymarcher
11-05-2008, 09:13 AM
Method #1: Use the Arch&Design materials "Special Effects" rollout.

...


Method #2: Use a light set to "Ambient".

...

/Z
Yes I am aware of that error. There is a still another way to get a correct ambient occlusion workflow with layering of shaders. The trick is to do "add" the keylight onto the ambient occlusion, this eliminates the indirect shadows in the direct light area giving correct indirect shadows.

In maya that was easy to do, I just used the fantastic mix8layer to add the direct light (a simple diffuse shader) on the ambient occlusion shader. Is is bummers 3dsmax doesn't have a decent shader yet for layering shaders for as far as I know. In vray it is the same problem.

MasterZap
11-05-2008, 09:37 AM
Is is bummers 3dsmax doesn't have a decent shader yet for layering shaders for as far as I know. In vray it is the same problem.

You have several choices actually to do this in 3ds max:

the Composite material
the Shellac material
the Blend material
For this I would recommend Shellac since it's a pure additive mix.


put your normal material as the base material
put a "mental ray" material with the Ambient/Reflective Occlusion shader as the surface shader in the "Shellac" material.
put the AO shaders "bright" to the same color/texture as the diffuse color of your base material

/Z

MasterZap
11-05-2008, 10:59 AM
BTW: I felt this topic merited a blog post (http://mentalraytips.blogspot.com/2008/11/joy-of-little-ambience.html)

/Z

Decency
11-06-2008, 02:30 AM
Zap, this may be slightly off topic for the thread but I just read your blog post and skimmed your site. This technique is new to me and I have a couple questions. Using the omni light with AO in the light shader the benefits I see are that you can get decent AO with very little overhead using any type of material and without leaving Max.

The downside I see is you have an ambient light now affecting your scene lighting. Do you have any thoughts on this? Is there a way to perhaps get the AO effect without the ambient light? The only way I had been able to achieve this effect globally was to render a separate pass (don't hit me!!) and composite. Using this method is there any way to darken or lighten the AO effect to make it more or less noticeable without affecting the scene lighting?

Either way I will be experimenting with this more and you have opened my eyes to a new workflow. Thanks!

custinyakis
11-10-2008, 06:20 PM
Wow MasterZap! Thank you very much for your effort! I learned a lot :applause:

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