Maxwell Render

Maxwell Render Information Repository
It is currently Thu Jun 20, 2013 12:38 am

All times are UTC + 1 hour [ DST ]




Post new topic Reply to topic  [ 30 posts ]  Go to page 1, 2  Next
Author Message
 Post subject: GENERAL: Emitter Presets
PostPosted: Sat May 06, 2006 1:47 pm 
User avatar

Joined: Tue Feb 01, 2005 4:26 pm
Posts: 966
Location: Madrid
Some basic concepts about lighting to understand what we are talking about :wink:

Luminous flux [Φ] Unit of measurement: lumen [lm] Luminous flux [Φ] is all the radiated power emitted by alight source evaluated with the spectral sensitivity of the eye and the photometric his radiation equivalent km.

Luminous intensity Unit of measurement: candela [cd] Generally speaking, a light source emits its luminous flux [Φ] in different directions and at different intensities. The visible radiant intensity in a particular direction is called luminous intensity.

Illuminance [E] Unit of measurement: lux [lx] Illuminance E is the ratio between the luminous flux and the area being illuminated .An illuminance of 1 lx occurs when a luminous flux of1 lm is evenly distributed over an area of 1 m2.

Luminance [L] Unit of measurement: candelas per square metre [cd/m2] The luminance [L] of a light source or an illuminated area is a measure of the brightness.

Luminous efficacy [η] Unit of measurement: lumens per watt [lm/W]. Luminous efficacy [η] indicates the efficiency with which the electrical power consumed is converted into light.

Colour temperature Unit of measurement: Kelvin [K] The colour temperature of a light source is defined in comparison with a “black body radiator” and plotted on what is known as the “Planckian curve”. The higher the temperature of this “black body radiator” the greater the blue component in the spectrum and the smaller the red component. An incandescent lamp with a warm white light, for example, has a colour temperature of 2700 K, whereas a daylight fluorescent lamp has a colour temperature of 6000 K.

Colour appearance The colour appearance of a lamp can be neatly defined in terms of colour temperature. There are three main categories here: Warm White < 3300 K Cool White 3300 to 5000 K Daylight > 5000 K. Despite having the same colour appearance, lamps may have very different colour rendering properties owing to the spectral composition of their light.

Color rendering Index CRI is a unit of measure that defines how well colors are rendered by different illumination conditions in comparison to a standard (i.e. a thermal radiator or daylight). CRI is calculated on a scale from 1-100 where a CRI of 100 would represent that all color samples illuminated by a light source in question, would appear to have the same color as those same samples illuminated by a reference source. To put it another way, low CRI causes colors to appear washed out and perhaps even take on a different hue, and high CRI makes all colors look natural and vibrant.

Image

Image

Image

Some common bulbs
Image

How to set bulb data in Maxwell
Image

In Maxwell we can set the intensity of the emitters with two parameters:
-His color given by RGB, or better, given by his colour temperature in ºK
-His Luminance or luminous flux, given by:
1- Nominal power in W and efficacy in Lumen/W. The Luminous flux is Power(W) X Efficacy (Lm/W) = Luminous flux (Lm)
2- Luminous flux in Lm if we can know this value. When we bought a bulb, usually this data is written in the box: Colour code (not allways colour temperature), Watts, efficacy or Lumen
3- Illuminance in lux. It's a luminoux flux per m2
4- Luminous intensity in Candelas.
5- Luminance in Candelas/m2.
The most common data for emitters is 1 or 2, so the presets are made with these.

Image

Image

We have to think a bit of the right exposure in maxwell cameras to have a good illumination in our scenes.
Common 35mm or digital cameras need to adapt his setting to indoor lighting. Some usual configurations with a room lit with common bulbs (in incandescent bulbs 100W for a 5m2 room, 200-300W for a 10m2 room, 500W for a 25 m2 room) are ISO near 400-800, fStop 4 or 5.6, and Shutter speed near 15-30. Otherwise, we need some aditional light with a flash to take this kind of photos.
The default Maxwell camera settings are ISO 100, fStop 8 and sSpeed 125, very common for outdoor lighting with sunlight

I hope you can understand some of my english. Feel free to ask!

_________________
- jose martin -


Last edited by jomaga on Sat May 06, 2006 1:56 pm, edited 1 time in total.

Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 1:50 pm 
User avatar

Joined: Mon Jan 10, 2005 11:53 am
Posts: 7619
Thank you Jose!

_________________
Next Limit Team


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 2:00 pm 
User avatar

Joined: Sat Feb 05, 2005 5:38 pm
Posts: 772
Thx dude very useful :D


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 2:22 pm 
User avatar

Joined: Fri Dec 03, 2004 9:56 am
Posts: 873
Location: Germany Hannover
WOW... very good Work jomaga :9 thanks

_________________
::
Donations revenue 195 Euro in 7 years ;)
::
everything my models (mathe and 3d-scan) not for Commercial use!


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 2:25 pm 
User avatar

Joined: Thu Feb 16, 2006 1:55 pm
Posts: 707
Location: UK
I'l agree with jotero. WOW. Thats a hellava lot of useful stuff right there... Cheers mate :D

_________________
I don't really take anything people say seriously until they've used at least 20, sometimes 25, words...


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 2:46 pm 
User avatar

Joined: Wed Jan 26, 2005 8:30 pm
Posts: 7406
Location: Uzbjeckiazutjenikitzistan
So much good info in here, great jomaga!

_________________
Next Limit Team
Merchant of happiness


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 3:25 pm 
User avatar

Joined: Sun Oct 02, 2005 1:11 pm
Posts: 77
Location: Italy t.d.g
a lot interesting! :D

_________________
- Sorry for my terrible English -

Image


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 4:31 pm 
User avatar

Joined: Wed Jul 20, 2005 9:51 pm
Posts: 715
Location: Copenhagen, Denmark
Wow, fantastic contribution to the Maxwell community .. thank you very much!

_________________
Lars Bjorstrup
http://www.xlars.dk
Maxwell 2, Max 2012, Win 7 64x, ASUS Rampage III Extreme, Intel Core i7 950 Quadcore 2.8 Ghz, 2 x Gigabyte GTX 280, 24Gb DDR 3 RAM


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 4:49 pm 
User avatar

Joined: Sun Jan 23, 2005 10:47 pm
Posts: 767
Location: lost
thx a lot for the detailed explanation and for having remembered to me why I was use to hate applied physics during university... :lol:

_________________
Do you want me to sit in a corner and rust or just fall apart where I'm standing? | Marvin da paranoid android


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 5:26 pm 
User avatar

Joined: Wed Feb 02, 2005 9:11 pm
Posts: 875
Location: Tampa,Fl USA
wow this was simply a wonderful overview thanks..

i'll have to print this out and post it on my wall to refrence, thanks!

It mentions the maxwell camera settings as default fro sunny outdoor scenes, and that to et indoor with incandecent to set ISO 400 and 15 shutter at 4 fstop OR touse a flash...

MY Question what is the power/tep on a typical camera flash?
Looking at the bulb picture chart I would guess to use a HALOGEN low tensionbulb -- what wattage is typical.. 50w-100w for a camera flash..

But looking at the rendered light pics.. Id saysomething "whiter"than halogen low tension is to be used.. maybe a cold florecent65 or a metal halide200w..?

I know its up to us and scene/look specific.. experimentation
But can you share what a typical camera flash bulb's stats are...

-thanks
-luke


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 6:23 pm 
User avatar

Joined: Sat Jun 18, 2005 7:26 am
Posts: 3215
Location: Seoul, Korea
Great tutorial. Thank you very much, Jose. :D :D :D

_________________
many limits team
:: twitter :: Gallery :: My 3D products :: ...and ::


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 6:36 pm 

Joined: Wed Feb 02, 2005 5:32 pm
Posts: 395
Location: San Pedro Sula, Honduras
Simplemente increible Jose, se te agradece muchisimo.

_________________
http://web.mac.com/nicolasrivera/iWeb/Site/Home.html


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 8:52 pm 

Joined: Fri Jan 21, 2005 9:16 pm
Posts: 402
Location: France
thanks, great info indeed...

_________________
De Humanis fabricae...
aka vesalus on cgtalk
aka vesale on frenchcinema4d


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 10:10 pm 
User avatar

Joined: Sat Mar 19, 2005 8:11 pm
Posts: 214
Just what I need!!!!
Thanks a lot


Top
 Profile  
 
 Post subject:
PostPosted: Sat May 06, 2006 11:22 pm 

Joined: Sat Jan 28, 2006 10:43 pm
Posts: 644
Location: bilbao
:shock: Gracias jomaga! Si no me aclaro ya con esto es que soy un poco t....

Saludos :wink:


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 30 posts ]  Go to page 1, 2  Next

All times are UTC + 1 hour [ DST ]


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group