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Macrob
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Post by Macrob » Fri Sep 07, 2007 6:52 am

Kram1032 wrote: can you close up, how you did it? :)
here you go

ööhhmm, no z-direction with the text mesh :oops:
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projector.jpg
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OnoSendai
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Post by OnoSendai » Fri Sep 07, 2007 7:00 am

Wow, I'm amazed you got it to focus correctly :)

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Macrob
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Post by Macrob » Fri Sep 07, 2007 7:05 am

trial and error x hours :wink:

BbB
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Post by BbB » Fri Sep 07, 2007 7:07 am

May I second Stompin. With a 50mil at 1.4 aperture, you would definitely get a somewhat blurry background. And since the image is taken inside, it's not at all an unrealistic scenario. Believe me, I've achieved far more insanely shallow DOF with such an objective.
(Very nice pic, btw. It feels very real to me.)

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Kram1032
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Post by Kram1032 » Fri Sep 07, 2007 7:18 am

great :D - that's a first attempt for the competition :D:D

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Macrob
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Post by Macrob » Fri Sep 07, 2007 7:25 am

get your own idea 8)


(C) :wink:


hmm, I think I´ll release it under the GPL3 :roll:

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Kram1032
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Post by Kram1032 » Fri Sep 07, 2007 7:34 am

that's not what I meant ;)

actually, overhead projectors, I know, are a bit different :)

the lens above the lightsource is a frenesel lens (I think) - and the quality is much worse, as you have chromatic dispersion from the frenesel and the single projection lens - you actually'd need to add those, to get it real... (I know... INFINITE computing time)

it's YOUR first attempt for the comp. that's what I meant ;)

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Macrob
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Post by Macrob » Fri Sep 07, 2007 7:49 am

I know about fresnel lenses and immediately after knowing what they are stopped thinking about modeling one :shock:


Yes, it´s my first attempt and I´m stuck :?

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Kram1032
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Post by Kram1032 » Fri Sep 07, 2007 8:00 am

I'm not sure,, if that would work properly, but you could try, to use a circular saw-tooth bump map to get a frenesel lens effect :)

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Macrob
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Post by Macrob » Fri Sep 07, 2007 8:34 am

as far as I understand this fresnel thing, every "tooth" has to have a different angle :?:

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dougal2
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Post by dougal2 » Fri Sep 07, 2007 9:08 am

yup a fresnel lens is just like a normal lens but "compressed" in (in this case) the vertical direction, simply by displacing concentric rings in the Z dir.

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Post by Lord of the Rings Junkie » Fri Sep 07, 2007 10:33 am

Macrob wrote:I know about fresnel lenses and immediately after knowing what they are stopped thinking about modeling one :shock:
Actually, I still need to perfect the technique, but I may know how to model one.
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fresnel.jpg
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Zom-B
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Post by Zom-B » Fri Sep 07, 2007 11:46 am

Kram1032 wrote:I'm not sure,, if that would work properly, but you could try, to use a circular saw-tooth bump map to get a frenesel lens effect :)
Best way to get a correct Fresnel Lense, check the Vector SVG on Wikipedia,
import it into your 3D app and generate a lense using it!
polygonmanufaktur.de

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Post by Lord of the Rings Junkie » Fri Sep 07, 2007 1:29 pm

Thanks ZomB, that image is really helping me figure this model out!:D (Mainly that the depth of each groove is the same, while the width of the grooves gets narrower towards the edge.)

[Edit] I did it! :D Here's a profile view of the fresnel lens I modeled and a side-by-side lighting test with the original lens. Guess which side is lit through the regular lens, and which is lit with the fresnel. :P
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im1189138807.png
Which is the fresnel lens?
im1189138807.png (434 KiB) Viewed 2835 times
fresnel_profile.jpg
Profile view of lens.
fresnel_profile.jpg (19.5 KiB) Viewed 2927 times
Last edited by Lord of the Rings Junkie on Sat Sep 08, 2007 2:30 am, edited 1 time in total.

Insquall
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Post by Insquall » Fri Sep 07, 2007 9:42 pm

OnoSendai wrote:there are limits to how much DOF effect you can have - because camera lenses / apertures just don't get that big.
unless you are stanley kubrik with his f0.7 lenses :lol:

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