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Rendering Techniques > Lighting and Shadow Basics-Part 1 (Posted By: cgking)
:: Post Date: 2007-04-11 20:17:01 [Post Comment] [Post Articles]

Lighting and Shadow Basics-Part 1

Software Used: Autodesk 3ds Max

Author: Montree T.

Email:easyyong@hotmail.com

Ambient Light

Ambient light is one of the most important parts of creating a realistic rendering becuase it sets the time and mood of picture that you are trying to create.

The complete scene should be composed of a specular pass, a diffuse pass and an ambient pass. Some artists use only the default specular and diffuse settings, but I always like to use ambient light only as a main ambient light.

The examples, below are done without the ambient only light seeting checked.

3D images by Layer3d@hotmail.com, http://www.thai3dviz.com/

Compare with the scene, done with ambient only lights (below)

3D images by Narin Assawapornchai (top) and Peangporn Boonmema (bottom)

So what color should we use for the ambient light in the scene? The color of the ambient light should be the average color of light affecting the scene + the average color of the entire room.

For example, skylight will influence a room with a large window or opening the most as the skylight (a kind of area light) will scatter around a large portion of the room or even throughout the entire room. So if the wall is a white or cream color, the ambient color should be blue(skylight) + white or cream which results in a yellow-green color. Also, don't forget to dim down the intensity of the color.
The sunlight itself will only affect the room in some parts, that is only the floor and walls as the sun is a directional light and it will not scatter around like the skylight, with exception to its indirect illumination from floor or wall. However, this indirect illumination will not have as much of an effect as the skylight.

If you still don't know what color you should use. I suggest that you go with a brown-grey first. I don't use pure grey as its lack of color will make the image look dead.

I have some suggestions about color below, but keep in mind these colors are not set in stone. You may use this as a guideline.

Example 1:

The color of a room with a small opening

Ambient only R= 142 G=139 B=116

Example 2:

The color of a room with a bigger openning

Ambient only R= 168 G=175 B=159

If we have any downlights or diffusers in the room, the skylight and sunlight are still considered stronger. If I give skylight multiplier = 1, the multipier of downlighs or any diffusers should be less. I always start creating lights whose multiplier is the strongest first.

The 2nd picture shows that the multiplier of skylight is equal or lesser than downlights.

Example 3:

The color of atmosphere of a room without natural light. Suppose the color or these down light is yellow.

Example 4:

The color of atmosphere of a room without natural light as well, but the light sources are more diffuse.

Ambient only R = 138 G =143 B = 117

Another interesting way to understand how to use color to make our renderings look better and more colorful is to understand color theory. I have read a number of books about painting written by artists. They always try to avoid black and grey becuase this causes images to look dead and colorless. Complimentary color is also interesting. An artist (I am sorry that I don't remember his name) says "Cool light(color) warm shadow(color) and warm light cool shadow." I am not too sure if this conflicts with our present science theory but as long as your work turns out very well and you call it "Art" , nothing is right or wrong. For example, if we see orange and blue (complemantary colors), you may think about evening time, as the color of sunlight appear orange in the evening and the ambient light is blue. Another example that is yellow and purple, yellow light goes well with purple ambient light.

Example 5:

The scene is filled with blue and orange light

Other Parts of This Tutorial:

Go to Part2

Go to Part3

Comments: (Currently there are 18 comments.)

[Anonymous]sachin ( 2008-11-13 22:28:55 ) [Post Comments]
nice work........thank
[Anonymous]akkc13 ( 2008-07-22 04:41:24 ) [Post Comments]
Great work...... thank
[Anonymous] ( 2008-04-21 22:09:25 ) [Post Comments]
？
[Anonymous]Kerpunk ( 2008-01-25 08:59:30 ) [Post Comments]

Agreed, Iam sure this tutorial has good intentions, but there is too many like this that dont provide step by step instructions on how to use the tools in the first place.

3D has no mercy for beginners

[Anonymous]superdan ( 2008-01-25 08:58:09 ) [Post Comments]
Cluless for a beginner
[Anonymous]budyholy ( 2008-01-14 18:33:37 ) [Post Comments]
this is useless, what i want is a step by step tutorial or procedure how this things happen.
[Anonymous]marc ( 2007-12-01 15:47:56 ) [Post Comments]
thanks for the tip. more power to you
[Anonymous]3dmax ( 2007-09-04 14:34:33 ) [Post Comments]
Wow, it's cool man! if u can post the lighting setup(in wirefame) image for us to refer, that will be a extra bonus for us to understand it more clearly. thanks ya!
[Anonymous]Leo ( 2007-06-26 22:34:41 ) [Post Comments]

I second to that...

[Anonymous]??what?? ( 2007-06-01 22:53:22 )

WHY CAN I DO THIS IN 3DMAX 8????? I HAVED TRYED 6 TIMES, BUT I CAN'T?????!?!!!!!!!!!!!!!!!!?!?!?!?!?!? @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

stupid tut!!!!!

[Anonymous]balamanikandan ( 2007-06-21 14:38:02 ) [Post Comments]
hello sir this is veryuse ful for me. i requst 1 more how will use in omni light,
[Anonymous] ( 2007-06-10 11:52:09 ) [Post Comments]

First i want to congrats to you, your job is precious...im a beginner in lights ,could you explain how do you create in the window the light of the sun, where did you put it?, or please if you could explain step by step this exercise,thanks!!!!!!

[Anonymous] ( 2007-06-05 02:23:28 ) [Post Comments]
very very thanks
[Anonymous]??what?? ( 2007-06-01 22:53:22 ) [Post Comments]

WHY CAN I DO THIS IN 3DMAX 8????? I HAVED TRYED 6 TIMES, BUT I CAN'T?????!?!!!!!!!!!!!!!!!!?!?!?!?!?!? @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

stupid tut!!!!!

[Anonymous]raj ( 2007-06-01 17:37:20 ) [Post Comments]
hmmmm.......good boy....
[Anonymous]Leo ( 2007-05-29 09:12:00 ) [Post Comments]

This is not a tutorial, this is more of a tips. Confused the hell out of me. You should at least posted a sourcefile with the sample lights you mentioned instead of lecturing us. Sorry man, this is useless for me.

[Anonymous]jo ( 2007-05-26 19:58:49 ) [Post Comments]
wow!,..this is quite helpful bro... thnx for the tuts and more power to u!
jo
[Anonymous]manu ( 2007-05-05 09:42:17 ) [Post Comments]
i am beginner thank u for teach
[Anonymous]phyothet ( 2007-04-21 15:25:36 ) [Post Comments]
i am beginner. Thank you for your teach.

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