Indirect Lighting Does Not Work (on my computer only it seems)

I am making a 3D mockup of a game prototype that I currently have working in 2D. I need to have the mockup finished before Monday of next week.

I have 3 long cylinders and one cube, the cylinders should emit light and the cube should reflect the light emitted by the cylinders. I turned emit on to 2 for all cylinders, diffusion up all the way for all objects, deleted the lamp, and set the world lighting to indirect lighting with approximate gathering.

Did all the steps correctly as thousands of tutorials show, yet there is no light reflecting off the cube, it’s just black. I thought maybe I had some incorrect default settings so I downloaded a few tutorial files that had everything already finished and indirect lighting on. Nope, still no indirect lighting.

With one tutorial however, when I had emit on one of the objects and rendered, DURING the rendering process it would FLASH a quick correctly indirectly lit image a couple times, but the end product would again be black (besides the emitting object). This confuses the hell out of me. I cant figure out why the hell that would happen.

I have spent the last 3 hours pulling my hair out meticulously going over every setting, watching simple tutorials which make awesome indirect lighting effects in under 5 seconds, then continuously seeing my render show absolutely zero indirect lighting.

I have found nothing by google searching “indirect lighting not working”, and the only thing I can blame for this is my computer, which also doesn’t make sense. I don’t really think there is a “Don’t Allow Blender To Use Indirect Lighting” spec for Windows 7.

Here is a picture of what I am seeing when I render:


And here is my Blender file
vivo3d.blend (544 KB)

Please help me.

Is there a reason for using the internal blender render. I would have thought that using cycles would have better. I took it your file and modified it for cycles. The wires have an emission of 5 and the cube has a mix of diffuse (red) and glossy (white). Camera angle also adjusted to get a good reflection of the blue and yellow wires.
[ATTACH=CONFIG]345509[/ATTACH]

blend file attached: [ATTACH]345510[/ATTACH]

Thank you for the quick reply and the help.

To me cycles looks very rough and sandpaper-y. With this game I was trying to go for a flat ultra smooth surface style which blender render does seamlessly.

Take this simple tutorial for example: https://www.youtube.com/watch?v=gr0kNnHscs0

That is the exact effect I am going for, yet when I follow the steps, clicking indirect lighting and setting the corresponding parameters does absolutely nothing to the render. It’s as if indirect lighting is switched off…

The problem is with the cylinders. They are too long. Curiously, If you move the centre to where the cube is then it seems to work much better.

blend file attached…[ATTACH]345513[/ATTACH]

The render form frm the BR only file…[ATTACH=CONFIG]345521[/ATTACH][ATTACH]345522[/ATTACH]

Hi Westron

The Indirect lightning in Blender Internal is an approximate technique, meaning that your mesh needs enough vertices to get accurate results. Your cylinders in the scene only have few vertices that cant contribute light because they fahr away the cube (Yes the lights only get emitted from the vertices not the faces)

So my recommendation: shorten you cylinders and subdivide them heavily till you get the result you want

Edit: Looks like BiggR was faster

AFAIK you can’t use mesh emitters in Blender Internal effectively, as BI is no global illumination renderer. Indirect lighting is about adding light bounces to CG lamps.

I’m unsure, though, why this seems to work if you move the red line’s center closer to the center of the cube mesh, but I assume this is an artefact caused by the “Approximate” gathering method. As soon as you switch that to “Raytrace” (the more precise calculation method), the cube is dark again.

So, in a nutshell: No mesh emitters in BI. If you want “real” GI, use Cycles. Increase the number of samples to get rid of Cycles’ “sandpapery” look (and perhaps activate Multiple Importance Sample for the mesh emitters).

BI doesn’t support Raytraced indirect lightning, thats why it stays black.

Ah, I see!

Thanks a lot guys! I guess I didn’t fully grasp the “Approximate” aspect of it. I moved the cylinder centers closer to the square and it worked better, I will try subdividing the cylinders a bunch tomorrow and report back.