Lighting

[H. Ikeda]

Hi,

Lighting is, you know, the most difficult aspect of cg creation.
Also it depends on what we want for a scene, or how it looks like.
When we leave from the basic 3-point lighting, we are lost in dark about how we should use a lot of lights.

In a technical meaning, lighting with some light objects is a simulation of indirect illumination, that is, radiosity. If in a room, we have a light and reflections on 6 planes (walls, ceil and floor), so it requires at least 7 lights from a very simple thinking. Sure this is too rough.

In actual scenes, we may need lots of experimentations on lighting, their positions, colors, directions, brightness, types (tube, area,...). In some cases, I think area lights may be helpful for simulating reflections on walls. For other cases, maybe not.

I think there is no general theory about lighting in cg. This also depends on taste, realistic level, kind of objects... that is, what you want to express with CG.

[Claudio72]

IMO light is very important

this is my lighting test over an head

head is ZERO in modelling
texture is ZERO

lighting is high vote IMO


http://www.crosio.com/images/light_setup.jpg

[LucentDreams]

H. Ikeda isv ery right, overall there is no true rules to lighting. THere are basic rule, especialy for certainstyles, but overall its all about what looks good.

Myself I come from a classical animation/illustration background for stylings and colour and such, so the three point lighting works for me and is the ruleI stick by, but doesnt' mean I wouldnt' abandon it in a second if something else looke nicer for a specific image. As for how many fills, haha now that we have light exclusion, I'm geting closer and closer to the concet of individual lights per object hehe. I"m not concerned as much abut if the light is all exact. for me its a matter of does each thing have its proper focus and value, doe things that need to stand out stand out? I will try to always have a good rim on any character and make sure even in a dark scene things are well lit.

What colour is a red tomato? RED? Well what about at night time when things are cool and dark? STILL RED? I beg to differ, its usualy purplish. Check sample a colour from a tomato in a nightscene photograph, it sure wont be totally red. What colurs is dark yellow. Well really dark yellow is brown, but you'll find that a lot of yelow often seems orange when darker. Don''t think that things always have to be light and dark, use colours to sho shade, don't use black shadows all the time, Id eally for realistic stuff alittle blue tinge should be there, but use coloured shadows if you want. its all a matter of waht looks good.

I try to apply tonal composition and colourtheory when lighting. but so far I haven't done a lot of scenes, ususally just characters standig and such.

[kiwi]

Ya I agree with all of that guys :thumbsup:


Nice pic Claudio :)


I thought this would be a good subject for a discussion :)



I have noticed lately as far as color theory goes that peoples faces seem to almost always have a natural {non CG,natural lghting} blue tinge where the fill light would be illuminating.



Stu.

[Claudio72]

here the three point lighting explained

http://www.renderaid.com/infoDetail.aspx?p=d&id=1006&sid=1001&f=aZ@D/]M_

[kiwi]

Thanks Claudio :thumbsup:



Those examples are from the book I read :) ...thanks anyway though.



I suppose I am after advanced lighting techniques,but then again its probably something you learn by trial and error.



I will be sorted well and truly when I can get my copy of XL8 going,and I can use a light for each object etc....am looking forward to that :)



Stu.

[flingster]

hey kiwi...there is some good stuff about lighting around on the web. my take on this and maybe with more experience it might change but i think there are rules to good lighting...its more technical than you might expect...yeah ok its a visual result...but the planning part is more technical than most people undertake...i think you gotta obey the rules...80% of the time...this still leave 20% experimentation and implementation.

what i would like to see though is kiwi write something on lighting cos i think you have a good eye for it....i remember once you sharing a file or tips for a scene and you used a blue area light above the scene...very subtle but very informed. i think your take on 2 fill lights is also very good....hence would like to see some tips or standard methods setups posted from yourself...would be very useful to me...and presumably to everyone else. that said it could be time consuming and you might not want to spend the time on this....maybe just a tricks sheet or something....please please...
:wavey:

[pit]

http://www.maxon.net/deepshade/shader/shaders/light/ix_light1.html

maybe these will be of some use, Flingster. Have not checked them myself - just remembered they were there...

[turx]

Carles Piles (my favorite c4d artist) has 3 making of tutorials on his site.

http://www.3dluvr.com/carles

those helped me a lot about lighting. And will help you too, i believe..


also Ila Solomon's lighting tutorial is great also:

http://207.219.13.92/ila_solomon/


and Amaan Akram has a great tutorial too:

http://www.warpedspace.org/tutorials.htm



I think it is more important "to simulate light's behaviours" than 3 point lighting.

[archrendr]

Light is as much implied as it is actual.
Being new to 3D I have the sense that lighting is about the most important aspect of good renders and also sometimes very difficult. I start checking the light almost as soon as I begin modeling. I have a default 3 light setup for any new scene unless I re-use an existing one again. Because I am new - I will tend to try most anything and have had some great accidents! The render on the left has one round spot outside and a very dim omni inside near the ceiling. Most light here is radiosity. Scene has a hot and overlit look outside which is accurate for the climate and for the feeling I wanted. Scene on the left has about 15 lights with one very predominant as a realistic sun. Some are inside the building and are colored. A slightly blue backlight and slightly warm fill light is used here. The foreground is intentionally dark - it tends to give light and color to the sky without actually adding another light source - which would not work that way anyway.

[flingster]

pit: thanks for the link never even noticed them...definitely worth looking at.:thumbsup:

turx: seen these except..Ila Solomon's which looks good...thanks for the links though.:thumbsup:

archrendr: having seen pits link and your comments it brings us to the subject of colour in lighting...eg blue for night time...basic etc. i mean kiwi is changing the light colour slightly on each light...what about brightness on each light seems to be a dramatic change...probably warms scene slightly...dunno will have to try it. Also i seem to remember someone posting temps and colour settings or something relevant to c4d? anybody got link...

still think kiwi ought to write a tut....believe me guys it would we worth reading and would help us all....imho of course...so i'll just keep begging...until he gives in....please please...


FOR ANY LURKERS OUT THERE SOME LINKS I POSTED IN TUTORIALS THAT ARE STILL WORTH A READ....
->
Lighting stuff - non app specific.
some lighting info and non cinema specific but very useful i found whilst browsing the net and some may have been posted on here before, hope they help.

course module for film makers etc. on lighting very very useful
http://www.cybercollege.com/tvp027.htm

lighting info
http://ansel.his.duq.edu/~woytek/mm507/module4/intro.html

expanation of key, back, fill, side, kicker, background.
http://www.3dark.com/archives/lighting_principles.html

tips
http://www.3dark.com/archives/lighting_tips.html

<-

[MJV]

The basic principles of lighting are pretty darn simple really. Study real scenes, look at where the light is coming from, how intense it is, what color it is, it's area/volume, and try to match it in CG. A red tomato is always red, and shadows are always black. But a red tomato will took different when illuminated with different colored light, and shadows will look a different color when the ambient color is something other than white.

[MJV]

Another key to realistic lighting is to not place lights were they cannot realistically be. Finally, I believe one the main keys to realistic lighting is to use realistic falloff. Cinema doesn't provide a realistic falloff model, so I made my own:

http://www.mvpny.com/LightFalloff.html

[artemesia66]

there's some interesting info here re: light colors, with absolute rgb values for different light sources. not sure that you can assign an absolute value to a light source, since any given light source will look different in different situations (ie daylight looks bluer coming into a window than in an image "exposed" for daylight), but fwiw. (flingster: is this the link you meant?)


http://members.shaw.ca/jimht03/light.html

[flingster]

artemesia66: thats the one...thanks appreciated...i can now bookmark it...:beer:

MJV: lightfalloff thats so damn clever...it annoys me...in a nice way...
good job...:buttrock:

[MJV]

Originally posted by artemesia66
there's some interesting info here re: light colors, with absolute rgb values for different light sources. not sure that you can assign an absolute value to a light source, since any given light source will look different in different situations (ie daylight looks bluer coming into a window than in an image "exposed" for daylight), but fwiw. (flingster: is this the link you meant?)

Of course I'm talking about relative colors. You have to figure out the white point of the scene (white balance) first, and work from there.


http://members.shaw.ca/jimht03/light.html

[kiwi]

This excellent info guys :thumbsup:



Flingster thanks for the kudos :D ,I am still really stumbling along myself as far as lighting goes :) I would love to write a tute for you but my health is not up to at the moment,kinda hard to explain but writing and doing lots of concentrating at the same time is exhausting.



Ah color some tips.


Warmer colors like yellows,oranges,etc tell our eye that the objects illuminated by the colors in the foreground.Hence when you paint a picture you use warmer colors for the foreground and darker or cooler for the background,which basically gives you a DOF or depth of field situation,so that you have distance.You can also create this sort of situation by adding a road or indicator which brings your eye into the area you want to be in the greatest focus,and when you add color theory to that it enhances it even more.


When you do a multi pass render try adding some of the material channels as well,for instance diffuse,as this controls your grime.If you want to increase your grime{In Photoshop}set it to multiply blend mode,or make a copy and do that.For lights screen mode is the best,again make a copy and just reduce the opacity to you get the lighting you want.


In C4D itself you can use a diffusion channel to reduce the amount of light on your object,but then you have to synchronize everything around it in the same way or it wont work.Its usually good practise to use diffusion in an accurate manner in your materials,but if you get stuck with an almost great light rig and one material screwing the scene try cranking its diffusion up a bit and see if it helps.


For specular its a good idea to keep in mind when you are modelling how your lighting will effect the edges in your render,so use beven or smooth shift to create an area that is not 90 dgrees geometry as everything your eye sees has a slight bit or bevel on its edges.



A new thing I do now is make a 2D noise shader,use turbulence and crank it up to about 160 or up globally,play with the high key,low key settings,get a nice spread then make the white about 98% grey and the other 96% grey.Click ok and leave the shader,the copy it into a hue shader {this works brilliantly for color as well}.Ok say you have to change the color of your 2d noise shader {not one set up for diffuse but color} then you have to individually change each color,but if its in a hue shader all you have to change is the hue,but best of all for diffusion of the color map just reduce the lightness slider :) ...brilliant in the diffusion channel,not perfect but ok in the color channel.



Another shader tip. say you have a fusion of black and white shaders and you want to control what black or white only goes through to the end material,but you also want a custom layer mask to use,what you do?,use screen mode for blending,the black will be totally filtered out.



For bump in metals I generally use 1% random noise and no black but 50% grey and white.Gives you more control of your bump mapping.When you use black and white,the black goes down and white raises,but the black can mess up the process so you add 50 grey and then you only have only bump in the non 50 grey areas as 50 grey registers as no bump.



A great Photoshop technique I use lately with the new 7 version brushes is add layer of 50% grey set to overlay above your BG and use the burn and dodge tools to paint on that layer,non destructive dodging and burning :) I seldom used to use dodge and burn but with the new brushes ad engine and my Wacom they are great.


I know my way around PS pretty well so a lot of that theory is very similar in C4D.


Ok thats about me :)



Stu.

[archrendr]

Hi again, yes, the old red tomato trick. I know that one but I probably think of it and use it in a bit different manner. I have placed a red sphere just outside the view of the camera and made it really big. When used with radiosity, it gives a warm glow to some areas nearby that cannot be accomplished any other way. A 'whatever' color would do the same. Is this about lighting? I think so because it is about 'seeing' which is not scientific on the level I'm interested in. I totally agree with MJV about the unpredictable falloff of Cinema's lights - at least I can't predict what the effect is going to be very well. However, unlike MJV, I will put a light anywhere I find that it adds to an overall effect or sense of appealing reality. I cannot possibly accurately predict how light reacts - AESTHETICALLY - until I try it. Scientifically innacurate? I surely don't care. I work to achieve art and poetry. It is truly in the eye of the beholder.

[artemesia66]

mjv: great tip about the falloff. how did you find this out? did you somehow measure the light levels in a scene?

[flingster]

kiwi: thanks for the tips bud...and keep well...no probs on the tut front...the tips are cool either way...i knew you'd have some funky ways of looking at things.

archrendr: red sphere...very nice tip...i'm gonna try that one...subtle i like it..:thumbsup:

[archrendr]

....remember you can put all kinds of render tags on it too - wrap it around something- look "through' it- and so forth.
Best, arch

[flingster]

yeah like the idea of looking through it also.

actually tried quickly your idea with a room we all used on a radiosity thread the backwall was out of camera view and tried with red/orange wall...but was to subtle...so i'm gonna have another go with it should come up looking sweet...thanks again for the tips...if you got any ideas about material settings on wall...might be useful i just used standard..with colour...but was thinking luminance channel orange 60%, colour red, illumination channel generate GI and recieve GI any ideas?
:thumbsup:

ps.kiwi sorry for slight detour...:shrug: , just curious..

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