Internal Light?

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  02 February 2011
Internal Light?

Hello everyone,

That question mark is there because I'm not entirely sure of the name of what I must be looking for...

I tried avoiding posting this question trying to find what I needed myself but I just couldn't figure out the 'technica terminology' so I decided to post my question here.

I'm trying to achieve an effect which seems to be quite challenging to me. Imagine a Firefly traveling through some tubes, which are thin enough for us to see the light fromt he outside but not transparent, we can only see the light traveling through these tubes.

The best example I found was this one:

Though being an animation of Neurons, it shows exactly what I am trying to achieve, a light that travels through a circuit of tubes iluminanting bigger areas, so we can follow the Firefly without actually seeing the bug, just the 'internal light'.

I experimented a couple of things but didn't get anywhere. So I was wondering if anyone here could point me on the right direction, no need of complete explanations (though they will be welcomed =D) at least, I'd like to know what am I suposed to be looking for so I can investigate myself.

Thanks in advanced!
  02 February 2011
Sounds like you trying to achieve diffuse transmission from behind an object. To achieve that you could either use the backscattering part of a Sub-Surface Scattering material or even just translucency on the tube's material.
  02 February 2011
You forgot to mention which software :P
This should take less than a few minutes.
  02 February 2011
Hahaha! Sorry! I was about to include that... But I thought it would be 'similar' concepts for all software and then the way to achieve it would be different...

I'm using 3ds Max 2010.

Thanks for the information Kanooshka, however so far, I'm not having much luck. I managed to test translucency on an object, and thought that it did the trick for a bit... But as soon as I rendered in Mental Ray the result changed and translucency disappeared.

I'm trying to figure out if there's a way to do it using SSS, but since it's a new concept for me I'm not entirely sure of what I'm doing... Hahaha

Any further help would be entirely appreciated =D
  02 February 2011
Create a Shellac material. Put your normal material in the Base Material slot. In the Shellac Material slot, apply an arch&design material. For the arch&design mat, set transparency to 1.0. In the material's advanced rendering options set the glass/translucency to thin-walled, and the refraction trace depth to 0. Then set the Shellac's color blend according to how much translucency you want.
This should take less than a few minutes.
  02 February 2011
Mmm... That was quite interesting though it didn't give it the effect I wanted. However, last night while attempting to fall asleep I thought of a couple of ideas which I'm going to try today... Will post you an update later on today ^^

  02 February 2011
Hello again!

I seem to be closer to what I'm trying to achieve! Hurrah! Your reccomendations were interesting but either modified the look or instead modified the oppacity... I wanted to see the 'insides' of the 'tunnels' being illuminated. So I carried on playing with SSS.

This is what I accomplished so far:

No Internal Illumination

With Internal Illumination

With Internal Illumination & Teapot

That's merely a test, (hence looking like the Fast SSS Skin) since the final product will be textured differently and the model's shape will change. But I'm trying to achieve this effect which will prove useful for the final product.

Basically, initially I modeled that structure by extruding polygons from a sphere and turbosmoothing, which made the inside of the object 'solid' (making light scatter through it when applying the SSS map). So I created a hollow space inside the structure and added an omni light inside it to illuminate the interior of that big space (Image 2).

Finally, since the Firefly is meant to stop at those big spaces... I want shadow to show the silouette of the firefly (and keep that Interior Light feel... Because despite being hollow inside... it feelos like there's still some inches of wall separating the inside from te outside).

That's why I tried with the Teapot to see if I can achieve a more distinct shadow... But I'm going to play with that and fiddle with parameters I'm not too concerned about that yet.

My next goal is to achieve that Interior Illumination feeling inside the thin tubes, like a bulb travelling through them. Any clues? Am I going to have to animate an omni light travelling through the tubes? Hahaha
  02 February 2011
Smile different ways

Tehre are differetn ways to achive...

you can make it in 3d as well... just use any kind of refraction... glossy refraction for the outer geomentry... and inside thhe object, you can use simple any light or even objects with a glow-shader or light material on it.

Keep in mind that the render time in 3d get's really high compared to a 2d post effect.

And this would be my way.. just render the 3d without the glow and moving objects.
Make a simple mask for the moving objects, and in post add any kind of glare, glow and blur effect... simple by exposing or any kind of shine effects.
  02 February 2011
Thumbs up add

or simple use an SSS Shader, again similar to any kind of other shader.. if mia_x or vray standard shader.... raytrace refractive... the SSS Shader of course...

that should do it as well....
  02 February 2011
Thumbs up test

just came home and tried it in about 5 minutes, this result:

low quality, low settings of course, but that's just a similar way you can achieve such a look....
hope that all will help you
  02 February 2011
That's pretty awesome! So is that a completely 3D Render or is there any 2D Post-Effect?

I might play around with it, but the one thing that seems to make me unsure about your example is that it makes the material look as if it was 'glassy'... My 'circuits' are meant to be 'organic'.

There will be no refraction and or transparency. You won't be able to see inside the circuits and and nothing will be reflected either.

If it helps I shall explain the "tubes".

These tubes system is made with Spider-Web. A conexion of tubes which is some sort of labyrinth. So when the camera is outiside this Webby-Tubes you'd be able to see light inside it and shadows... But no actual shapes inside because it's not transparent.

Which is why I seem to be getting better results with SSS, however I stil need to fiddle with the settings... Because so far it's giving me the result with the lighting. I think that making a Light follow a path will give me the best results. (Any suggestions are still welcomed).

Now I'm wondering how am I meant to make this SSS (which seems to be used originaly for Skin) look like any texture I want to create (I'll make my own Webby-Textures), not sure how the maps will work... But it's something I'll try and figure out ... And I guess that if I have any questions regarding this matter I shall post it in the 'Textures' Topic as oposed to 'Lighting and Shaders'... (??)
  02 February 2011
Smile just 3d

the render above is just 3d.. no post work done...
if you don't want to have the glass-look, just change the glossy reflection parameters, and the IOR.

it really doesn't matter.. you can use an sss shader, or just a simple mia_x shader, or vray standard shader ... all the shaders give you some basic attributes for that....

if you want to have it more organic, like skin, you can either use the sss shader (again) or you use a simple shader with glossy reflections, and a IOR around 1.2-1.4. Translucency, glossy refraction and glossy reflection depending on the final look you want to achieve.

not to mention, that the reflection always depends on the environment.

the example I've posted contains no environment at all, it's all black;
it's just the object, and inside a sphere with a self-illuminating shader.
  02 February 2011
Hello again!!

I've been doing several tests trying to achieve the best result, and I must say that thanks to you I got some nice results. Using a SSS and an internal object with Self Illumination gives me a really good effect.

However, I encountered a new problem. It seems to only work well when the camera is close to the 'action', if the camera moves away, instead of seeing the same thing, but further away... The 'Self Illumination' seems to stop working and you end up loosing that effect.

Is there a way to solve this? Is there a particular radius which allows you to visualize said Self-Illumintion and once you're out of it, it won't calculte it?

Thanks again!

EDIT: Well, if I remove the outer geometry, you can see the inner-self-illuminated one as a fully bright white material, but once the outer geometry is placed, the effect of going through the SSS surface only applies to the meshes closer to the camera... Thought I'd point this out.

Last edited by Ant55 : 02 February 2011 at 12:35 PM.
  02 February 2011
Thumbs up atmosphere

you need atmosphere that scatters the light coming from the light source....

the sss shader works fine so far, and of course you only can see the ss in real life if you are close the object... as instance, take an ear from a human head... and behind that ear place a light-source that shines through..... and from front you will get the ss

if there is no more atmosphere that transports the light, it will fall off immediately.

if you want to do that in 3d... fasten your seat belt and add an environment fog.
to control everything I would also render the fog on a separate layer... so you can adjust in post.

but keep in mind, for such things of renderings... I wouldn't deal with 3d... render time is heavy, and you would get faster and easier very nice results when using just some masks and shine effects in post, which I mentioned earlier.

happy rendering
  02 February 2011
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