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Converging beam of light problem
In C4D there is parallel light & diverging light. But I need a converging beam of light.
I must see the beam after it passes through an object, so I use inverse volumetric. I tried faking it using a spotlight with a 180º rotation. But it’s almost impossible to get the result I want. So I need absolutely (I think) a converging beam of light. I tried sending a parallel bean through a converging lens. Doesn’t converge . The beam just goes straight. Refraction doesn’t work. Any solution ?Is there a way to reshape the box of a square parallel spot ?
iMac 24″, OSX 10.6.2, Vue 7.5 Inf, modo 401, C4D 11.5
https://www.claude3D.com -
6 Replies
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The only way I can think to do it, other than using the reversed spot, would be to use volume caustics in conjunction with a lens object.
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Never used caustics before. So, went to see what it was for in C4D. Yes, theoretically should do what I want. Found an example at Maxon. The fish tank example. Had to stop the render after 44 min. It was still preparing photon tree. Not good for an animation, especially if the beam is changing shape constantly. But I have learned about caustics. May be useful in the future. Thanks a lot Adam.
Anyone has another solution ?iMac 24″, OSX 10.6.2, Vue 7.5 Inf, modo 401, C4D 11.5
https://www.claude3D.com -
I’ve found a few animations on YouTube using caustics with C4D. Umh .. The example I followed was maybe not appropriate. I’ll spent the day digging further. Any simple tutorial on caustics with refraction, not reflection?
iMac 24″, OSX 10.6.2, Vue 7.5 Inf, modo 401, C4D 11.5
https://www.claude3D.com -
I don’t know of any tutorials. Another thought: you might be able to do this by modeling an object for the light beam and using a material with the fog channel enabled.
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I suppose reflecting the beam off a mirrored parabolic surface doesn’t do it??
What about using mograph to clone a load of spotlamps distributed along a suitably shaped slpine or over a surface.
I’ve no knowledge of caustics I’m afraid.
Alan
FlashXDR,XDcamHD,XDcamEX,D9 etc
FCS,AE,Combustion,LiquidSilver,Vegas,Edius,
G5,MBP,Vista64,XP -
It works. I mean volume caustics works. Instead of trying to find a tutorial , I went with trials & errors.
In this picture the light ( a parallel spot on the left of the picture) is shooting into the lens ( a sphere flatten setting the size z=0.1 and made it editable). Visible light must be set to volumetric ( I may have a problem there as I use inverse volumetric). You can vary the focal distance different ways : curve of the lens (playing with the z size) or the refraction index.Here you can see a bit of reflection coming back from the second surface of the lens. If you don’t want that just uncheck exit reflections in your lens’ transparency material.
Note: z is the axe of my light beam
If you want to try it, here is the .c4d file (R11.5)
iMac 24″, OSX 10.6.2, Vue 7.5 Inf, modo 401, C4D 11.5
https://www.claude3D.com
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