KeyShot Forum

Technical discussions => Rendering => Topic started by: Rydi on March 18, 2014, 06:50:05 am

Title: Light through glass and liquid
Post by: Rydi on March 18, 2014, 06:50:05 am
Hello everybody

Do you know what is the best way to achieve light reflections on the ground like that ?

(http://img11.hostingpics.net/pics/758752unnamed.jpg)

I tried to add a sphere on the scene and then apply a light as material, with all options checked on the rendering pannel but my result was very grainy... not smooth at all, I can't give you a preview now but i'll do. Before that, anyone have a Idea ?

The result is very very smooth, I think the material ground matter, as well as the lighting.

Thank you guys !
Title: Re: Light through glass and liquid
Post by: Rydi on March 24, 2014, 07:50:34 am
Hi guys,

I hope with a screen you will see what I am talking about, look in the picture all the dots of light, i want something smooth, but even with my ground with 128 samples, my caustics at 10, the quality shadows to 5, i have this result ...

Any idea ? I use a HDRI environnement black with just one spot of light.

On the left this is a screenshot of keyshot, on the right the final render.

(http://img15.hostingpics.net/pics/29165486aa.png) (http://img15.hostingpics.net/pics/21660765b.png)

Thank you !
Title: Re: Light through glass and liquid
Post by: Rydi on March 24, 2014, 12:00:43 pm
I really don't like to reply to my own topic and create multi post but if someone have an idea I will really appreciate :)

Title: Re: Light through glass and liquid
Post by: richardfunnell on March 24, 2014, 12:32:22 pm
Hi Rydi,

Can you share this scene with us?
Title: Re: Light through glass and liquid
Post by: Rydi on March 25, 2014, 11:35:32 am
Hi Richardfunnell,

Here is the scene, if you achieve something that will be GREAT :)

Title: Re: Light through glass and liquid
Post by: Rydi on March 27, 2014, 03:37:03 am
Hello here :)

Maybe this is not possible ?
I don't think so but if no one can answer maybe it is :s

Title: Re: Light through glass and liquid
Post by: KeyShot on March 27, 2014, 12:32:03 pm
I recommend you try using the realtime renderer for this type of scene with a detailed caustic. You can use the max samples approach, which will render the scene as long as you use enough samples.
Title: Re: Light through glass and liquid
Post by: Rydi on March 28, 2014, 01:33:08 am
Okay thanks for the tip ! I keep it ;)

Title: Re: Light through glass and liquid
Post by: DriesV on March 28, 2014, 05:37:56 am
I gave this scene a shot today.

I did one of my usual tricks of doing separate passes for general lighting and caustics.
The reasoning behind this:
* Point lights generate the sharpest/fastest caustics, but are not suitable for general lighting of your product.
* HDRIs with multiple 'light pins' (which is probably what you want for HQ jewelry/fashion ware) cause caustics to take a long time to converge.
Attached is the result after compositing in Photoshop.

Here (https://drive.google.com/file/d/0Bw6BI0tv_sN8NTFDUlk2bjVlQUk/edit?usp=sharing) you can download a zip containing:
* KeyShot packages with scene files for both the base and caustics pass
* EXR renders out of KeyShot (base & caustics)
* Photoshop working doc
* Final image

I did this really quickly.
You can get better results with some more tweaking in KeyShot, more render time and better compositing.

I hope this is what you're looking for... :)
At least I had a lot of fun taking your scene for a spin! ;D

Dries
Title: Re: Light through glass and liquid
Post by: DriesV on March 28, 2014, 05:56:16 am
Btw,

I'm not usually the guy to self-promote, but recently I hosted a KeyShot webinar where I covered the process of rendering and compositing this way:
https://www.youtube.com/watch?v=IY626fh_Xcs&feature=youtu.be (https://www.youtube.com/watch?v=IY626fh_Xcs&feature=youtu.be)
The section about caustics starts at around 54:00.

Dries
Title: Re: Light through glass and liquid
Post by: edwardo on March 28, 2014, 06:03:37 am
Those caustics are amazing Dries. Can you let me know (roughly) how long each render took and the spec of the machine you rendered it on?

The reason I ask is that Im having speed issues getting to this level of quality. I'm playing about with caustics for the first time (I'v got V3 but playing with V5 beta at the moment). I will open these .bips and take a look at your settings and see if its feasible to render on my laptop (mbp 2014 2.6quadcore i7, 16gig ram)

@Rydi... Good luck with getting your scene the way you want it - I hope Dries setup points the way.

Thanks
Edwardo
Title: Re: Light through glass and liquid
Post by: DriesV on March 28, 2014, 06:11:07 am
Ed,

This was rendered on a i7 3930K machine (88fps in camera.bip on KS4.3).
The caustics pass (2500*1250) rendered for 45 minutes. (You can probably get faster results with advanced control rendering...)
The base pass rendered for less than 10 minutes, I think.

Dries
Title: Re: Light through glass and liquid
Post by: DriesV on March 28, 2014, 06:23:55 am
As for rendering with advanced control: the caustics quality can be increased by dialing in a value of up to 100.

Dries
Title: Re: Light through glass and liquid
Post by: edwardo on March 28, 2014, 06:36:01 am
thanks Dries
Title: Re: Light through glass and liquid
Post by: Rydi on March 28, 2014, 08:05:06 am
Dries i'm gonna look your file soon because i can't right now, but when i'm watching your result I just want to call you God.
So thank you, a lot :)
Title: Re: Light through glass and liquid
Post by: KeyShot on March 28, 2014, 08:10:11 am
I second that. Dries is the master of caustics!
Title: Re: Light through glass and liquid
Post by: DriesV on March 29, 2014, 05:01:47 am
I'm really curious to see your final image!

Henrik,
There wouldn't be any mastery without your wizardry. ;)

Dries
Title: Re: Light through glass and liquid
Post by: Rydi on March 31, 2014, 07:27:24 am
Hi everyone, this is the final image (I think), thank you again Dries !
I took your file and actually even if you did that quickly I changed just a little bit the angle and increased the power of the point light.

You really helped me with that ;)
Thank keyshot also to make it real !
Title: Re: Light through glass and liquid
Post by: DriesV on March 31, 2014, 07:40:25 am
Ouch, that's awesome!!

Dries
Title: Re: Light through glass and liquid
Post by: thomasteger on March 31, 2014, 08:04:15 am
Very well done!
Title: Re: Light through glass and liquid
Post by: TpwUK on March 31, 2014, 08:34:27 am
A little shove in the right direction from the right is all it takes at times, excellent render Rydi

Martin
Title: Re: Light through glass and liquid
Post by: Esben Oxholm on March 31, 2014, 09:20:21 am
Nice. Pretty good looking.
Title: Re: Light through glass and liquid
Post by: DriesV on March 31, 2014, 10:30:27 am
However, it would be very nice if there were a toggle to disable caustics for HDRI...
This would eliminate the need of having to do separate passes.

Or... Maybe a caustics render pass? ;)

Dries
Title: Re: Light through glass and liquid
Post by: Rydi on April 01, 2014, 05:53:43 am
Thank you guys for the comments and +1 for the caustics pass :D
Title: Re: Light through glass and liquid
Post by: edwardo on April 01, 2014, 05:59:05 am
Really nice work Rydi, and well done for persevering till you got it right. Its funny, I look at Kate Moss and assume she's smelly. Curious what her perfume smells like?

Good work
Ed