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I am working on project where I am using an infrared light. I want to simulate my real scene on blender. I am using a Cycles Render engine. I want to choose a point light. It is possible to fix a level angle visual range (45 degrees in the real scene)? The viewing range (80meter in the real scene). Any explanation will be appreciated. I need to simulate this light: enter image description here Illuminating range: Standard 45° Viewing range: 80m (outdoor)

I used the solution proposed in the create an array of lamps? to model the Infrared light mentioned above which has these properties:

  • Led quantity: 96 leds.
  • Wave length: 850nM.
  • Illuminating range: Standard 45° level angle visual range
  • Viewing range: 80m (outdoor).

The fisheye camera is installed in the ceiling in a room.

When we use the wave length node, the array of lamps does not emit a sufficient light!! enter image description here enter image description here enter image description here

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BetterEnglish
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    Not sure what you mean... You want a point light that has angle limits, like a spotlight and a distance limit? – Bithur Feb 07 '15 at 17:27
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    I don't understand your question. Are you asking for parameters of the light source or for camera parameters? – maddin45 Feb 07 '15 at 17:31
  • @maddin45, my question is about light source. – BetterEnglish Feb 07 '15 at 17:34
  • @Bithur, I edited my question – BetterEnglish Feb 07 '15 at 17:34
  • related: http://blender.stackexchange.com/questions/24391/how-to-create-an-array-of-lamps/24392#24392 –  Feb 07 '15 at 23:56
  • The following page may be useful for you when it comes time to add all the lights. http://blender.stackexchange.com/questions/24391/how-to-create-an-array-of-lamps Unless you are using geometry lights, then you should be fine for the array part. – MarcClintDion Feb 08 '15 at 11:40
  • @Bithur, it is possible to specify the wave length for a spot as in a real case. – BetterEnglish Feb 08 '15 at 15:42
  • there's a wavelengh node and blackbody (temperature)in converter submenu – Bithur Feb 08 '15 at 15:57
  • @Bithur, What is the units of Strength in Light FallOff. it is in meter? – BetterEnglish Feb 08 '15 at 21:04
  • I really don't think so. As far as i know, maddin45 told you how to stop light at the exact distance you want but i wasn't able to find a good way to get a nice falloff. Someone with better math or coding knowledge could do better. – Bithur Feb 09 '15 at 00:13
  • @startingBlender if you emit light in a wavelength that is not visible... what are you expecting to see? –  Feb 09 '15 at 02:58
  • @cegaton, you are great. Excuse, I suppose that the camera is sensible to infrared wavelength!! – BetterEnglish Feb 09 '15 at 03:08
  • @startingBlender I think in terms of your simulation the wavelength should not be relevant, unless you are to create some object that has a material that transforms the infrared energy into something that can be represented with the colors of the spectrum. –  Feb 09 '15 at 03:13
  • visible light and its wave length : https://en.wikipedia.org/wiki/Visible_spectrum – Bithur Feb 09 '15 at 04:08

3 Answers3

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If you want to keep it in cycles, you'd better model your own lamp as anything can cast light. This way you can control the shape and with a light falloff node you can control the distance.

modeled spot

assign the correct shader : emission for the face you want to cast light, plastic or anything else for the other parts.

Bithur
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Add a Spot Lamp to the scene, switch to Blender Render engine and set the Spotlights size(angle) and distance(falloff).

enter image description here

Position it in the scene like you want, the visual spotlights guides will help, you should see the spotlight cone and range.

Switch to Cycles if you want, but the falloff will not work there, you will have to adjust the light's strength. If you like you can use volumetrics to visualize the lights cone in render:

enter image description here

It will look like this:

enter image description here

Jaroslav Jerryno Novotny
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Disclaimer: This answer might be better suited as a comment, but since you can not post images in comments I created an answer instead.

Sounds to me like you want to use a spot light. Spots work similar to point lights but also have an opening angle. Unfortunatly Cycles only supports round spots, not rectangular ones.

About the viewing range: In real life light will not stop abruptly, so this parameter does not really make sense in a physically based renderer like Cycles. You can however mix the emission shader of the spot with a holdout shader depending on the ray length to only make it illuminate objects in a certain range.

enter image description here

The result looks something like this:

enter image description here

At a certain range from the lamp the lightsource is treated as black. This creates the hard round 'light borders' to the left. The soft 'light border' to the right is where the opening angle of the spot ends.

maddin45
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  • Thanks, but I remark that the shadow is not very clear and in the real case, the Infrared light is a monochromatic, so we get grayscale image not RGB. So, I think I have to choose precisely the diffuse of the spot. – BetterEnglish Feb 07 '15 at 18:04
  • @startingBlender I only wanted to demonstrate a method to make the light stop at a certain distance here. – maddin45 Feb 07 '15 at 18:41
  • really interesting but i'm trying to make a falloff with raylength. Something like an inverted exponential. As you can guess, my maths are not good. – Bithur Feb 07 '15 at 19:02