Light Energy Problem

Good day Blenderers,

I have a scene completely inclosed from any outside light source. Like in a tunnel with both ends sealed.
I only have 3 lights in the scene. Two spots and 1 area light.
When I turn the energy of all three to -0-, I’m still getting some light. Where I"d expect it to be completely black.
Can anyone give some ideas how I can make a few frames completely dark?

I’m trying to achieve a fade in & out effect. The light doesn’t go completely out.

Thanks for everything,


ubuntu jaunty

do you have ambient occlusion turned on ?

Use a combination of spot lamps with soft fall off and lamps with the sphere option enabled.

Here’s the process that usually works for me, although it’s a bit complicated…

  1. Open your .blend file
  2. Select the lights in your scene
  3. Go to the lighting tab (under materials)
  4. Open your web browser
  5. Go to
  6. Scroll down to the Support (texturing and lighting)
  7. Post your question there instead of in News

I keed, I keed

did u check if u hav turn your lights shadow casting on or off,coz if one of them is off,your scene wont be completely dark

It doesn’t seem to make a difference wether it’s on or off. I turned it on and set the energy there to .001 as low as it would go. I also adjusted a few other settings with no difference.
Thanks for giving me a place to start.


Hey thanks for this tip. Now that I think of it, I recollect seeing that forum.
Please accept my apologies.

I didn’t see a thread from you in the other recommended forum yet, so I will reply quickly here to your situation while I have the chance.

This is a very quick solution:

Place a black (Shadeless, non-Traceable) plane in front of the camera, perhaps parenting the plane to the active camera (if it is moving) and/or keying the location of the plane to sit just in front of the camera for the frames you need complete darkness.

Should render faster as well for those frames :slight_smile:

The plane method also offers this bonus:

You can key its alpha (with ZTransp on) from 1.0 to 0.0 and back for fade-ins / fade-outs or irregular dimming while the plane sits in front of the camera.

Good luck with your project!


Yes, this is what I was had done in the first place. However I thought it would be better to use the energy. Reason being, when I’d move the plane once I was through with it, I’d sometimes see the edge of it.
So I deleted the plane and it was then I realized I can not turn energy to zero.
I have tried, at least to the best of my ability all other suggestions provided here. All of them have been helpful in one way or another.
I’ll just go ahead and put in a new plane to block the camera. Parenting it and leaving it there is a great idea too. Thanks!


PS: would someone kindly like to put this post where it belongs?
Sorry for any inconvenience. I’ll be much more careful not to let this happen again.

That is even simpler to fix:

When keying the Location of the plane, insert a Loc key on the very last frame you want the plane to be before it is to disappeare, then on the very next frame key (where it should not appear) place it completely out of view.

This example assumes you were using the default Bezier interpolation mode in the keyed IPO curves for the object instead of Constant, which can be more suitable for circumstances where an object is to remain at a certain size, location, and/or rotation until a certain frame, upon which changes occur without interpolation.


Instead of Loc you could key the size of the plane using a similar method as above, waiting until the last frame you want the plane to appear then to Scale it down on the next frame to 0 and then key its size.

Or, instead of Loc or Size (scale) of the plane, you could either key its Alpha or Layer (switching it back and forth between visible and non-rendering layers).

Lots of ways to go about it :slight_smile:


could you just use negative lights set to 0 energy placed on the ones that are fading and when it gets to really dark set the neg lights to >0?