multiple fluorescent light panels

Any suggestions on how to make realistic light panels? What I’m trying to duplicate is the lighting in suspended ceilings.

I’d like to use blender internal - I don’t think yafray likes me yet. Or is it the other way around?

Too bad everything doesn’t just need sharp shadows - I’m getting GREAT at that!

Arealights can emit from a rectangular area, make an area light and set it to be a rectangle.

CD is right about the area lights. With multiple samples they will give smoother shadows. I didn’t know if you intended to see the light fixture in your scene. If so, is this sort of what you want:

The light fixture uses meshes with Emit and then an Area light suspended below it. Also turned on AO to give more depth to the lighting. Here is the blend if it will help:

is there a way to get the exact shape of the light output of a real fluo fixture
or is it only approximative


@RickyBlender: Since the light from a Flou fixture is diffuse. You could use Radiosity in BI or use a unbiased engine like Indigo. I bet you are tired of hearing about Indigo by now. LOL.

To checkout radiosity check out:

ok i’m an elec eng and do a lot of lighting design so may be i should have told that before
my question was more from a very specific technical point of view
i don’t know what your background is - i i’m a bit confuse on how i can say it to make you understand my question !
a square fixture fluo 2 x 4 ft with diffuser under it will light in a square pattern
it’s not like a point source of light
so is blender or yafray able to simulate such a source of light or ism it very approximative?

what the hec is indigo anyway - i got yafray and yahoo and that’'s enough lol
i got read more about radiosity
have you ssen the next version of Bl will have major change for the internal renderer
i hope it will come out soon to see this new feature


This is Indigo, it’s really good!

but for the time being i’m trying to stick with BL and Yafray
may be in an another life i’ll try indogo lol

i did a test with radiosity and the top of 2 cube i put in a room are so dim that i’m certain why but if you have any idea let me know !


@Brucewestfall: I hope this discussion is helping you too. If not give us a shout and we can open a new thread.

@RickyBlender: If you want to project a square light path, you can set a Spot Light to Square. However, unless a light is very intense you do not generally see a square projection from a square fixture. Instead the light diffuses the farther it gets from the lamp and light bouncing off of walls and such add more ambient light. In the scene I did above I used the Area lights and AO to represent the type of light I see in the 2 x 4 flou lit room in front of me.

In CG everything is Fake. The lights in blender use simplified math formulas to approximate lights. however, you will never be able to add one single lamp in a scene and make it look “Real”. There is always a need for other lamps or AO or other lighting tricks. Unbiased render engines like Indigo use complex math to figure the path of individual light rays as the bonce around your scene. This means they are closer to the way real lights work, but it takes a very long time to render all those individual rays.

Either up the emit value of the cubes, or in the radiosity settings, one of the buttons multiplies the light strength, i think its the one that is set to 30 at default (sorry I dont have blender on this PC so I can’t look atm).

there are softwares that calculate precisely the effect of light look at manufactuer of lighting products - no name for the time being. and i do use them but wen i’m inblender their model is only very approximative of the reality.
so there is a way but it’s always a question of time ot render and how close to reality

  • mind you these programs use a point by point calculations to get the final results
    and they do have with the distribution curve for the light in the proper light intensity - lumen or candlepower curve for spots ect,

and it is time consuming for the Computer
may be blender should adopt one of these model where you can enter a ligth curve and do a point by point calculations
i’ll check the render panel to see how to increase the light intensity


@Ricky: I know Indigo uses IES models for lights. Which generates different light patterns based on the data in the IES file. For blender you can approximate this effect by adding an texture to your lamp. For example: Say you want a ring light, you take a nice image of a black ring on a white background, load it as a texture, calc alpha on it, and apply that texture to your light. Now the light broadcasts a ring of light instead of a full circle of light.

your beginning to interest me with this indog
are you saying that indigo can load up lightning curves of fixture as specified in IES or manufaccturer datasheet for fixture and it will use it

may be i’ll download that thing fast
and does it mean you have to change or redefine the lamps in blender to use this
is there a good tutorial for this aspect from a technical point of view

2 - itri9ed to follow the manual for radiosity but obiously something is not working i check the render radio and radio tool and st parameters as indicated but still no much light on

mind you the rendering time is around 3 secondes that’s strange!


@Ricky: Re: Indigo. Yes it load the data from a set of supplied IES files. (I think you can get other IES files on the net). You chose the IES file as the material in the Blendigo exporter script. Indigo does not use Blender lamp settings. The one draw back to Indigo is that it is young and has little documentation. You will need to search the Indigo forum for most of the how-to steps. But from what I have seen there the guys on the Indigo forum are as happy to help as we are here (in fact several are the same folks). As for the Radiosity it has been far to long since I played with it to remember the hows and whys, sorry.