lighting and emitance question

Hello, this is my first post after looking at all the info on here for quite a while.

I’ve used blender to make some space craft but I have problems when I try to add lights to them.

I first tried puting a light on the side of the ship but discoveded you can see where the light comes from only where it is reflected. Secondly I made a coloured, transparent sphere and put the light inside, however the light never gets out of the sphere. Finaly I tried using the emitance value of the sphere but the light it emits doesn’t seem to reflect of anything so I don’t get the desired look of the light on the side of the ship.

Is there a fix for this? So I can see the light bulb and also have it reflect of the ship.

Also if I want to animate the ship I can seem to move lights along with it, is there a fix for this too?


you need to use the radiosity feature to get that some reflection
from other object around and also some shadows would be nice too
may be some AO ambiant occlusion too
may help a little


I had a problem exactly like this one to solve several months ago. It is solvable, I can tell you. How? I can’t tells you exactly because I would have to rediscover the solution. But it have to do with allowing the globe to not cast shadows if I remember. This allows the light to pass through. And the globe needs to have some ambience and/or emitance. Sorry I’m not of much more help but I hope I gave you usefull directions.

You need transparency and a low alpha value.

Here is a .blend:-
This one is better(I don’t know how to delete attachments)

untitled(2).blend (434 KB)


untitled.blend (90.4 KB)

how can you save to JPG file
i tried and i don’t see pic in folder ?

how come the Rad i render panel was not set
i mean if you want to see color reflection on other object it should be set
but shadow and trashdow were also set


On the Render format panel, change the save image as format - I often use .exr as it is lossless and floating point, a bit like .bmp

There is a Lamp inside the sphere. lol

what do you mean by lamp

it’s the source of light inside going thourgh the hemisphere
whic is colorless and transparent

and this does not affect the radiosity beause is normal white light ?

i’v been looking for something like this i think for a long time

and may be you have a solution here to get some radiosity around
with light source inside

now what about color
i mean if you add a colored lens instead - is it going to work ok?

in field many times you have a colored lens with an ordinary lamp inside
the color being provided by the lens not the lamp
because you could set a color on the lamp itself i guess
but not looking as real in the render

i’ll do another test for saving thefile


see pic

i’d like to see some radiosity around a 1/2 colored sphere
with a neutral white lamp inside

which seems to be very difficult to do !


I mean “Lamp”:-

it’s the source of light inside going thourgh the hemisphere
whic is colorless and transparent
On the first file I uploaded, yes; on the second, no

and this does not affect the radiosity beause is normal white light ?
The light is red in both cases.

now what about color
i mean if you add a colored lens instead - is it going to work ok?
I don’t know - (I didn’t test it) - but probably not.

Is it possible you downloaded the first attachment, before I edited? There is another there now.


Can you use a coloured light instead of white?

in field iit’s usually the lens that is colored and crate some radiosity around
with a white light inside

don’t know if there is any trick that can be used to get an equivalent
see pic of scene

the lens can be almost any color like white yellow red green blue amber violet

so i did put a small lamp inside but when i turn on radiosity i don’t see any color outside the lens

don’t know if it is possible in blender
may be i have to use a spot
i know that a spot will color shadow when shinning though a stain colored glass
is there a special name for this effect in blender?

may be i can use this here ?

what do you think

I didn’t use radiosity, just a coloured Lamp.
Do you have Raytracing enabled on the Render Panel?

oh yes i do! ray is on

see pic

but this colored shadow though glass i don’t think you can do this with another type of lamp it’s only yhe spot light that can do this
don’t know the name of this effect?

and also the shadow on lamp

but the shadow on lamp is black

may be that’s the problem but shjould still see it on the grey cube?


You can have coloured shadows with the Lamp. I am using an svn build, I don’t know if this feature is available with the official 2.48.

Do you want it to look like this?

get some color from the lens around
but just a little

i did some experiment with transparency and spot

now i put the pic in the wrong post sorry

see post for the pic

to do thsi effecdt do i need a special SVN built ?

but think the pic shown in post is about the same effect is it not ?

did you use any AO to do that?


No, you don’t need svn, 2.48.1 has coloured shadows.
I don’t think raytraced coloured shadows works through ‘glass’ but it will work with Z Transparency

No, I didn’t use AO.

ok i move my spot to the righ the yellow lens
used only white spot with ray set and use inverse square attenuetion + sphere limitations

that’s beginning to give interesting results
as expected to shine a little around but not too far
see pic

we can some yellow on cube at base and some on the push button on the right
but just a little effect - it’s beginning to look very nice

adn the last pic is with 3 spot lights

now the only thing missing would be to see a little more the lens itself
but don’t think it can be done

and emis is not good it would complety erase the lens itself !


Is this any help? It does use emit, though.

ya that’s beginning to be brighter

would you have a sample file for this

seems to be nice - i think i’d like to try it

i tried with emis at 0.005 but it’s like i’m loosing the brighness of the lens
and it’s almost totaly transparent

unless i try with a thick glass with 2 layers may be that’s the trick here
and set some mirror value too to get some refraction also?

i wish there was an example like this in wiki page
that would help other people too for this type of effect
which is not obvious at all


Sure thing. It uses a Blend texture UV mapped to the sphere.
untitled(2).blend (94.9 KB)

I hope it is suitable.


Here’s a blend and pic that might be helpful for the original poster (radm4). I didn’t use any transparency. Instead, I made the bulbs unaffected by raytracing or buffered shadows. I’ve used point lamps with raytraced shadows. The pic was rendered with soft shadows, but I turned them off in the blend because they slow things down.

I also parented (CTRL-P) the lamps to the block they are on so they will move at the same time.

Hope this helps.


Lamps.blend (226 KB)