Someone please teach me how the diffraction works

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yonosoy
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Re: Someone please teach me how the diffraction works

Post by yonosoy » Fri Feb 14, 2014 1:25 am

Hi. Well, out of convention scene ...
Things work quasi perfect (at min. 10 it's close, but 2 h is not enough for a perfect effect.
Working around this (for "exteriors" (outdoors).
...Discovering some cirscumstances about the filters now... The pigs more over inspected.
Suggestions are wellcome.
Attachments
stavaganza.jpg
"... the hamster don't see the wheel, and this wasn't said before." (yoS eidaN "el Olvidao")
"... nor 0.2 galaxys, nor 0.8 little chikens ..."

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Pibuz
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Re: Someone please teach me how the diffraction works

Post by Pibuz » Fri Feb 14, 2014 2:30 am

Hi yonosoy!
Cool scene, but a little too complex IMHO I must say..

At least you can spare some time converting the base mesh material to diffuse!

What did you use here?
Diffraction? Obstacle? Both?

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CTZn
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Re: Someone please teach me how the diffraction works

Post by CTZn » Fri Feb 14, 2014 3:11 am

the simplest setup is the camera facing a skyless sun.

if I'm correct, using the same map for diffraction and as obstacle should result into the same than using the diffraction map alone.

While the diffraction map is more often of high density details (patterns even), the obstacle map shows easier with large patches. My clasic is a distorted disc, as to alterate the round bokeh's.
obsolete asset

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yonosoy
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Re: Someone please teach me how the diffraction works

Post by yonosoy » Fri Feb 14, 2014 4:42 am

Hi again.
Usually the generated aperture is used, and now the obstacle map is a great element to complete nice effects.

300 s/p (200 seconds). For 3.8.
Is only a simple but very reach example. Every material, every sun position, every maps or parameters...
In order to investigate it is required to manipulate the XML ...
A specular material works faster for the base. Water without cauchy.

Update.
obstacle_chart_reference.jpg
obstacle_chart_outdoors.jpg
The trick is simple: a igi solution serves as evaluate all the obstacle maps required.
Actually is necessary to resume the igi, then pause (or not) and activate aperture. Then save it.
This lines are required in the camera section:

Code: Select all

		<obstacle_map>
			<path>glare_obstacle_cf_1.png</path>   -> direct the map here
		</obstacle_map>
Don't know what happens when aperture is defined as map (feeling that is unchangeable).

Thanks in advance.
P:D. a cross writing.... :) Thanks for the interest. The pigs is better now...
Attachments
obstacle_test.pigs
(3.11 MiB) Downloaded 94 times
Last edited by yonosoy on Fri Feb 14, 2014 1:56 pm, edited 2 times in total.
"... the hamster don't see the wheel, and this wasn't said before." (yoS eidaN "el Olvidao")
"... nor 0.2 galaxys, nor 0.8 little chikens ..."

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fenerolina
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Re: Someone please teach me how the diffraction works

Post by fenerolina » Fri Feb 14, 2014 1:47 pm

Nice one!

Just tested your scene and looks pretty fast. Will try to reproduce something similar in sketchup, as I have no experience on editing xml files and start some tests..

Pibuz, I think yonosoy's scene or something similar is good enough to test those maps . I also think that sun should be part of the scene. Reflective objects + diffuse walls = time, so what do you think?

The autosaved image doesn't show AD for me too, did you solve it? Don't know what plugin you're refering to, something that puts square flat emitters over teapots? sounds good but what's that? :lol:

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Pibuz
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Re: Someone please teach me how the diffraction works

Post by Pibuz » Fri Feb 14, 2014 9:14 pm

One that makes teapots, to tell the truth..

Sun appearing is cool! Go on!

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fenerolina
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Re: Someone please teach me how the diffraction works

Post by fenerolina » Sat Feb 15, 2014 6:54 am

All right, here's my simple scene. If you render it more time fireflies might appear. I also updated the maps list for further tests. Also tonemapping is on camera so depending on the maps you will have to adjust the ev. Left sphere is default phong and the other is specular transparent. Check the image commets for explanation.
Attachments
glare.zip
Renamed maps and add 1 more from galinette.
(3.01 MiB) Downloaded 97 times
AD_test_scene.zip
sketchup file
(46.05 KiB) Downloaded 89 times
scene.png
nothing special.
a.png
aperture shape: hexagonal. Blade offset 0.1, blade radius 1.1, angle of rotation 90. No obstacle maps.
b.png
aprerture shape: hexagonal (same parameters for the blades) + obstacle map o_fingerprint.
c.png
aperture shape: image: a_square. No obstacle map
d.png
aperture shape: image: a_square2 + obstacle map o_fingerprint.

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yonosoy
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Location: Spain

Re: Someone please teach me how the diffraction works

Post by yonosoy » Sun Feb 16, 2014 6:12 pm

Hi. Learning some optics rules. 90 seconds test. Films dimensions.
List of approximate equivalencies (a multiply table).
Constant params:
Exposure, field of view, focal distances and tonemapping.
Variables params:
Sensor dimension, focal length and F stop (take in account that the cam is rotated).

1.33:1 (mm) --- 2.067 (mm) --- 1.33
8:5.33 (mm) --- 11.0 (mm) --- 8.0
16:10.66 (mm) --- 22.0 (mm) --- 16.0
24:16 (mm) --- 33.0 (mm) --- 24.0
36:24 (mm) --- 49.5 (mm) --- 36.0
72:48 (mm) --- 99.0 (mm) --- 72.0
Nature is exact ...

(don't know why the images are too much compressed ...)
Attachments
dimensional_test.pigs
(20.83 KiB) Downloaded 86 times
1.33.jpg
8.0.jpg
16.0.jpg
24.0.jpg
36.0.jpg
72.0.jpg
"... the hamster don't see the wheel, and this wasn't said before." (yoS eidaN "el Olvidao")
"... nor 0.2 galaxys, nor 0.8 little chikens ..."

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