Unform Scale Omni Lights?

[chalk]

Hi all, im just following this tutorial i found on interior lighting. http://www.cgarchitect.com/resources/tutor...d/tutorial3.asp

 

They mention scaling down the omni light so it fits into the room, with a more oval shape instead of round. Anyone if this can be done?

 

Also A few other things in this tuturial have totally spun me out, in that i can't relate the terminoligy to C4D.. Read this paragraph for example...

 

"2. Creating soft shadows from area lights and indirect light

 

I usually make 2 layers of shadow for my interior scenes. The first layer is for the shape of the shadow from light source and the second layer is for soft shadows from indirect light and area light. The different look between soft and sharp shadows makes the scene look more fuzzy and realistic.

 

Basically, I always have one free direct under the ceiling and make the multiplier as small as possible. A typical value might be 0.1-0.2 and the color as dark as possible. What I want is only the soft shadow of every object in the room on the floor. Make the shadow color light grey and change the shadow density to a negative number like -1, -2 or -3 with a sample range as large as possible ie. 28-50. The negative shadow seems to be the easiet way for me to fake the area shadow. The advantage of the negative shadow is that it saves time during rendering. The negative shadow will appear darker or brighter depending on the color of the ambient light, so if the shadow appears very dark, you can reduce either the color or shadow parameters.

 

Casting these types of shadows is not limited to the floor. Sometimes I also place this kind of direct light to cast the shadow onto the ceiling or even on the wall."

 

 

Free direct light? Multiplier? Sample Range? Negative density shadows?

 

Anyone got any ideas what these things are?

[STRAT]

i think thats a max tut.

 

this is how i light my c4d interiors -

 

1) first i'll set my gi diffuse depth to 1. this is important because its by far the fastest gi setting. you dont need any extra bouces than this as you'll be compensating with infill lights, which will give you an equally real image.

 

2) place a sky object around the whole scene with a luminance of 100-200% off-white blue. this is the general gi shining in through the windows.

 

3) put in a infinate spot out side for your sun. turn on hard or area shadows, and turn the luminance of it down to about 60-70%. this is your sun shadow caster.

 

4) then i'll place omni lights with hard/area shadows where there are actual lights in the scene (ie, where there are actual ceiling lights, or corner lights, or table lamps etc etc). these lights then need appropriate fall off. (done by experimenting.)

I'll almost always use ranges for my lights instead of actual fall off as it's less harsh and softer. you should now have you local strong illuminaires done.

Also, when setting them up, use hard shadows as they render much faster than area shadows. when happy, then switch to area shads.

 

5) then insert maybe 2 omnis in the room for general ambient light. usually distributed equally spaced in the room these omnis should be ambient only. turn off all diffuse and specular. give them soft shadows at 30-50% strength, and make their illumination about 10-15%. you can slightly colour them too to give extra effect.

 

this is my basic interior lighting set-up for cinema. it's a case of tweeking the general ambiants then to get nice lighting. you can always add more locally placed ambient fill-ins if needs be. you dont need falloff or ranges on these, but it certainly helps in certain circumstances.

 

each scene is individual, but my method is a nice simple way of doing it. Take a look at my interior shots in my website. all done in this way.

 

allot of tuts make things sound daughnting and frightning with hundreds of settings. this is usually arse in my experience. i like to keep things uber simple. cinema has beautiful lights, so use them in their purity rather than faffing about with them.

 

you general rule of thumb is - set your exterior lighting with sun and global gi, then set up strong omnis (with fall off) where there are lights in the scene, then put in very low light emmitting omnis as fill in lights.

 

p.s. - dont forget to supliment your scene with an AO pass afterwards. adds to the gi beautifully

[chalk]

Thanks loads (again!) for takin the time to respond.... a great help!

 

I ended up trashing my last WIP as i forgot my original light setup and couldn't get it to look the same, so i figured i'd just start again. I'll have another go with the method you just described as well

 

Just one thing. By Ranges do you mean clipping (in 9.1), after following that tutorial i played with the far clip as i presummed thats what he meant by 'attenuation' (so many names!)

 

I'll post some kind of image tommoro.

 

Later.

 

Chalk

[STRAT]

attenuation. yes. just use far clip. from 0 to wherever.

[chalk]

hi all,

 

This is the latest result of much tweaking and messing around.

 

I couldn't reproduce the kindof look from the first image for some reason, i just forgot all the settings so started from scratch.

 

Strat - i started by applying your method but ran into problems when i realised the only light source would be the sun. How would you go about getting a light 'sunny' room effect? I've put in an omni grid of lights at 2%, the sun, and few area lights outside the windows and then put a 3 on the diffuse setting to get this image..............

[AJLynn]

That's pretty good. Sometimes you can get GI lighting to work with just sun and sky, but usually it helps to fake it a bit. Usually, the more of your light comes from the actual source the better. I think you've got a fill light too bright on the right wall.

[STRAT]

 

Strat - i started by applying your method but ran into problems when i realised the only light source would be the sun.

 

no, the sun is the only direct light source. the other light source i mentioned is putting in a gi emmitting sky object.

[chalk]

^^

 

Oh yeah thats in there to.

 

I might post the scene file a bit later - if anyone fancies messin around it would be interesting to see how other people light this scene - i've played with it so much im having dreams about omni lights, and Gi settings. Very sad

[STRAT]

i've played with it so much im having dreams about omni lights, and Gi settings. Very sad

 

join the club

[erona]

join the club

where are the application papers

[chalk]

Just curious. What kind of settings do you guys use in your interiors. Max. Min. Stoch samples?

 

Im just rendering another version of this scene with

 

200 samples

 

5 min

 

and

 

50 max

 

also it's at 85% acuraccy

 

 

.... im getting a few blotches, specially around the coving and places like that....

[erona]

ur MIN is way too low for my opinion. try playing with this setting 1st with the other settings on low and maybe start with 20 up until you hit the fastest and nicest result then stick with it.

 

up max considerably in general maybe around 100 or more.

 

play around with the accuracy setting, maybe around 70-85. put compositing tags on objects which needs more GI or detailed (ie. cornices, coving, etc) and raise the accuracy individually until splotches disappear.

 

raise samples to at least 500 IMO. up it if necessary.

[STRAT]

Just curious. What kind of settings do you guys use in your interiors. Max. Min. Stoch samples?

 

Im just rendering another version of this scene with

 

200 samples

 

5 min

 

and

 

50 max

 

also it's at 85% acuraccy

 

 

.... im getting a few blotches, specially around the coving and places like that....

 

yup, incorporate what erona says too.

 

i'll typically use for interiors - strength 100, accuracy 70-85%, pre-pass 1/2, diff depth 1, stoch samps 600-800, min 50+, max 600-800. and i'll use an AO pass too.

 

as mentioned, your min samps can drastically alter render speeds. 5 is waaaay too low. keep upping that value until you reach optimom render speed. also, i'll heavily use render tags on objects to alter gi and aa accuracy.

[chalk]

Cheers again for all the advise. I also just got 3d Fluffs 'interior radiosity' DVD today so i'm felling happy and enlightened.

 

I also just bought myself a new system - AMD duel core 4200 with a nice 2gb of ram and a 512 7900 GTX....... funny enough the thing that spured me to take the plunge was rendering this scene; my system just kept crashing when i bumped up the settings and was also starting to do it on my clients renders. So annoying.

 

Either way i managed to save this image b4 the crash and did a bit of work in photoshop. It's something to post, at least until i get the new system and can render it properly.

 

I've also included a random one i made a few days ago for comments - a bit dark but i was in a dark mood

 

Laterz

 

Chalk