Lens for distorting light

[vid2k2]

If you mean something like this,
then add a bump to the front surface that the camera sees through.

HTH

Edit:
...... and with light

[Erik Heyninck]

Light scattering because of its passing through a transparant object... aren't you talking about caustics?

[JIII]

haha yeah, it's surprising how few people actually use caustics these days, they aren't THAT slow, and they look damn good.

I guess what is wanted is a non-caustics answer to this question?

-J3

[nycL45]

Light scattering because of its passing through a transparant object... aren't you talking about caustics?

Yes, basically. I'm interested in distorting the wall/floor light and shadows after passing thru glass block in an interiors scene. May or may not be a close-up. If I were rendering a glass of wine, I would use caustics. Caustics is slow, yes?

For an interiors scene, are you referring to Light Object Caustics or Render Settings Caustics? Both? I ran a test using the Render Settings Caustics and there was no appreciable difference. Yes, I need to read the manual.

As JIII thought, I am looking for a non-caustics solution which Per-Anders and AdamT referred to in an earlier thread (my first post here).

[JIII]

I don't know what kind of computer you are using, but I was able to make good looking caustics, with not a terrible time hit, on my 500 mhz G3 using XL 7.3 years ago. If you really CAN'T make caustics work, try this solution, but seriously, 'caustics will probably give you the best solution, and unless you have serious computing issues, I would try it.

-J3

[telnoi-c4d]

You can cast caustics from a low polygon version of your object and hide the object with a cam tag. Usually, the difference between hypernurbs 1 and 3 is hardly noticeable, but it results in faster render times.

Not a non-caustics solution, but it might help.

[nycL45]

I am not doing a still of wine glasses or wedding bands so I have stayed away from basic and volumetric caustics. I do archviz and may use a partition of sand blasted glass, shower enclosure distorted glass or glass block to be viewed from a distance in an interior scene.

JIII, although my machine is on the boring end of the Cinebench listings, it can chug and grunt most of what I am currently doing. I am hoping for a whirling dervish this year.

telnoi-c4d, thanks for the suggestion. The idea I had was to use a distorted plane on the outside of a window or in the air space of my glass block.

vid2k2, suggested an interesting solution, a gobo, which I have not tried yet. (Thanks Dave.)

[JIII]

mmhmm, a gobo or a caustics cheat, there are alot of tricks that you can do to make 'caustics alot faster. i.e. a focused spotlight (omni lights take 6x as long to do caustics) and a low-poly caustics catcher, hidden inside of your high poly model.

-J3

[nycL45]

...(omni lights take 6x as long to do caustics)-J3

hmmm, I didn't know that. Thanks.

...a low-poly caustics catcher, hidden inside of your high poly model.-J3

What is a "caustics catcher" and what is the recipe? It sounds a little like my interlayment to distort the light.

[JIII]

Alright, so you have a huge high poly object, to run caustics through that would take a long time right? So you create a cube or low-poly object in the middle of you other object, apply a compositing tag, and only check "seen by compositing" not seen by rays or camera or anything else, that way it looks like the caustics are being generated from your heavy high polygon object, but it's really a fake :-).

Omni lights generate 6 different shadow maps because they are going in well, all directions. Spotlights only generate one, as they are focused in one direction. If you use spots + caustics catcher your caustics render time will be lowered significantly.

-J3

BTW Post # 4,000 for me :-).

[Rev9]

You need to use a virtual lense with mesh delineated internal volume and non-parallel surface caps and not a plane which has no volume. I have simulated camera barrels with multiple lenses thiis way from the Oil Tank primitive.. Just make editable->connect and distort one or both caps and you will ge what you need.

best Regards
BT

[nycL45]

...create a cube or low-poly object in the middle of you other object, apply a compositing tag, and only check "seen by compositing" not seen by rays or camera or anything else, that way it looks like the caustics are being generated from your heavy high polygon object, but it's really a fake :-).-J3

Thanks JIII. I'll give it a try. It sounds like it will give me the subtle treatment I'm after.

BTW Post # 4,000 for me :-).

Eyeow! My Congrats on the 4K!

You need to use a virtual lense with mesh delineated internal volume and non-parallel surface caps and not a plane which has no volume. I have simulated camera barrels with multiple lenses thiis way from the Oil Tank primitive.. Just make editable->connect and distort one or both caps and you will ge what you need.

best Regards
BT


Hey, Thanks, BT. That sounds cool and I'll try it on. Instead of editable->connect, did you mean editable>explode segments? Also, the distort you mention is that the material editor>texture>effects>distorter? My glass block is like your m.d.i.v.a.n.s.c. but flat on the outside and convex in the airspace. See the wire below. Perhaps there is no apparent light distortion due to the symmetrical lenses restoring the light to what it is on the exterior side after it exits the inner lens on the room interior side.

Leonard

[Rev9]

Your glass blocks need more polygons in them to get the proper surface rumpling. For distortion you can use a noise with the scale set to 300 to 500% using SPD. I would probably hypernurbs subdivide the mesh twice and make two materials..One for the internal surfaces which to my memory are not as distorted as the surface of the glass blocks. The same material as far as color and refraction, transparency etc. but with the SPD distortion channel turned on on the faces via selection tags will give the various surfaces enough non-parallel angles to distort the image. If you want frostiness you can add noise set to .1% in the bump channel..

Best
BT

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