Author Topic: Trying to create shadows with prisms  (Read 3923 times)

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Offline cheeyoon

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Trying to create shadows with prisms
« on: November 03, 2015, 02:50:08 pm »
Hey guys,

I'm trying to create shadows with prismatic materials for small objects I've modeled to achieve realistic effects as shown by attached images below. Any idea on how I can go about this with Keyshot? I've searched everywhere for tutorials but no luck. I've tried numerous different glass materials, refractive materials, settings, but the shadows just don't do anything close to the reference images.

Thanks in advance!

Offline TpwUK

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Re: Trying to create shadows with prisms
« Reply #1 on: November 03, 2015, 02:53:18 pm »
DriesV did a study with caustics generation with KeyShot v5 ... I will see if i can find them, or maybe he will jump in before I do. I will return and edit this post with link if i find it :)

Martin

** Edit **
I did find this old thread of some of DriesV's results when he was experimenting and researching caustics with KeyShot 4.1 https://www.keyshot.com/forum/index.php?topic=7902.0 I thought they were v5 related. I must be getting old :)

I think if you send a message via the KeyShot forum to DriesV i am sure he will offer advice and help to get the results you are looking for :)
« Last Edit: November 03, 2015, 03:26:54 pm by TpwUK »

Offline cheeyoon

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Re: Trying to create shadows with prisms
« Reply #2 on: November 03, 2015, 11:24:08 pm »
Thank you! I'll definitely have to message DriesV

Offline DriesV

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Re: Trying to create shadows with prisms
« Reply #3 on: November 04, 2015, 03:02:56 am »
This can definitely be done in KeyShot. :)
I tried to mimic the posted image as close as possible. Despite the unknown variables (prism dimensions, lighting environment, post processing...) I think I got pretty close.

Attached is a KeyShot 5 package containing the scene I used for the rendering.
The 'magic option' you were looking for is Caustics. :) In KeyShot 5 the option is found in: Settings (realtime tab) > Advanced > Focused Caustics.
Caustics works great in combination with the realistic refractive materials: Solid Glass, Dielectric, Gem. The dispersion parameter for the Dielectric and Gem material additionally allows to get a realistic separation of white light into colored light.
Caustics may take some time to resolve, although they should be very fast if you use a Sun & Sky HDRI and/or Point Light as the main light source. As a general rule: Caustics are faster with small (point-like) light sources.

In KeyShot 6 (to be released soon) Caustics will be even faster in combination with the new Interior Mode. ;)
I attached a KeyShot 6 image as well...

Let me know if you have any questions.

Offline edwardo

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Re: Trying to create shadows with prisms
« Reply #4 on: November 04, 2015, 03:08:17 am »
I don't want to join the technical discussion... I just wanted to point out that these are beautiful abstract images  :)

Ed

Offline cheeyoon

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Re: Trying to create shadows with prisms
« Reply #5 on: November 04, 2015, 03:14:31 am »
This can definitely be done in KeyShot. :)
I tried to mimic the posted image as close as possible. Despite the unknown variables (prism dimensions, lighting environment, post processing...) I think I got pretty close.

Attached is a KeyShot 5 package containing the scene I used for the rendering.
The 'magic option' you were looking for is Caustics. :) In KeyShot 5 the option is found in: Settings (realtime tab) > Advanced > Focused Caustics.
Caustics works great in combination with the realistic refractive materials: Solid Glass, Dielectric, Gem. The dispersion parameter for the Dielectric and Gem material additionally allows to get a realistic separation of white light into colored light.
Caustics may take some time to resolve, although they should be very fast if you use a Sun & Sky HDRI and/or Point Light as the main light source. As a general rule: Caustics are faster with small (point-like) light sources.

In KeyShot 6 (to be released soon) Caustics will be even faster in combination with the new Interior Mode. ;)
I attached a KeyShot 6 image as well...

Let me know if you have any questions.

Amazing...thank you so much for the insight. I'm checking out the file now and getting myself familiar with the caustics options, messing around!

I'll def let you know when I'm stuck or have any other questions regarding this  ;D

Offline DriesV

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Re: Trying to create shadows with prisms
« Reply #6 on: November 04, 2015, 06:32:06 am »
It can be worthwhile to pull these sort of images through Photoshop to tweak curves and colors.
It just adds a little more punch. :)

Dries

Offline cheeyoon

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Re: Trying to create shadows with prisms
« Reply #7 on: November 04, 2015, 04:12:53 pm »
It can be worthwhile to pull these sort of images through Photoshop to tweak curves and colors.
It just adds a little more punch. :)

Dries

:D of course!

Technical question: what are your render settings? The lights come out as grainy spectacles and I can't get that smooth look you achieve.

Offline DriesV

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Re: Trying to create shadows with prisms
« Reply #8 on: November 05, 2015, 09:07:46 am »
I believe these were rendered at 256 samples (Maximum Samples mode).

Dries