KeyShot Forum

Gallery => Amazing Shots => Topic started by: Hossein Alfideh on June 12, 2016, 12:57:39 AM

Title: practice scene
Post by: Hossein Alfideh on June 12, 2016, 12:57:39 AM
Hello guys
There are a lot of unfinished stuff I've left behind so I decided to make some changes in my old renders.
As Will told me to , I chose a scene from "Focus" film to practice what I had in my mind.
There is somthing I did not notice before ... Do we need to use an IES light to have the caustics? The environment light alone did not help so I add an IES but the shadows got a bit weird!  ::)
How can we avoid this?
Title: Re: practice scene
Post by: LayC42 on June 12, 2016, 02:47:20 AM
Playing with caustics is not that difficult. You'll need a strong light source. And this can be defined within the HDR environment or with a physical light source (like an IES).
And you need a ground plane. That's all, the rest is tweaking the parameters till you're happy or amazed.
Just watch the last webinar from Richard Funnel. He explained some things about caustics.

Hope that helps a bit
Title: Re: practice scene
Post by: Hossein Alfideh on June 12, 2016, 04:56:32 AM
Quote from: LayC42 on June 12, 2016, 02:47:20 AM
You'll need a strong light source. And this can be defined within the HDR environment
I guess my environment brightness was a bit low , on the other hand by increasing brightness other parts would become so bright that the whole thing becomes unrealistic.
Thanks for the information.
Title: Re: practice scene
Post by: LayC42 on June 12, 2016, 10:00:22 AM
So, a physical light will help to bring in a local bright light.

Perhaps the example could help
Title: Re: practice scene
Post by: Hossein Alfideh on June 12, 2016, 12:21:08 PM
Quote from: LayC42 on June 12, 2016, 10:00:22 AM
So, a physical light will help to bring in a local bright light.

Perhaps the example could help

Thanks for sharing man!
In these two following pictures there is no IES light ... I have increased the brightness but still the caustics wont show up!
I dont have problem using IES lights for generating caustics but my problem in the first place was that using another light source like an IES would generate a shadow which is different from the HDR lighting shadow and these two wont overlap ... this looks like there are two main lighting sources in the scene which is true and also its hard to move the IES to the perfect position to have a single clean shadow instead of two!!
Title: Re: practice scene
Post by: Esben Oxholm on June 12, 2016, 12:50:19 PM
Hi Hossein.

In the HDRI-editor, try adding a pin with a small radius and with a really high brightness in the same position as the sun in the HDRI, instead of increasing the overall brightness of the HDRI. Might help.
Title: Re: practice scene
Post by: Will Gibbons on June 13, 2016, 10:05:37 AM
Quote from: Esben Oxholm on June 12, 2016, 12:50:19 PM
Hi Hossein.

In the HDRI-editor, try adding a pin with a small radius and with a really high brightness in the same position as the sun in the HDRI, instead of increasing the overall brightness of the HDRI. Might help.

Esben beat me to this, but in this case, it's what I'd do.
Title: Re: practice scene
Post by: syrom on June 13, 2016, 11:36:35 AM
Looks good but the super high reflectivity of the spoon is killing it. Maybe increase the roughness and a very gentle bump