[Carrara]Shadow Catchers

[digitalarena]

Greetings all, this is no ordinary shadow catcher question. I have already read everything the Carrara Manual has to say on the subject.

My question is this:

How do I make my cast shadows less intense?
I don't want totally black shadows, I want some of the backdrop image to show through.

The manual does say: "The surface you apply to the Shadow Catcher object provides the color and transparency levelof the shadow." However I have tried changing transparency and colour and always get black shadows. Maybe you have the answer. If so, would appreciate your wisdom.

Cheers.

[digitalarena]

OK, I have found an answer - so for anyone else in this situation here it is:

The intensity of the shadow (e.g. how black it is) is NOT controlled by alpha or transparency.

It IS controlled by GLOW.

Give the shadow catcher a pure white glow and you get lighter shadows. Reduce the glow and the shadows get darker.

I have not tried different coloured glows yet - I will leave that to you.

Happy answers.

Cheers.

[rickei]

glad that works
I have never had a shadow catcher work like the manual says.
the only thing i have had to work in the past was adjusting the shadow intensity in your lights properties.

so does glow give it soft shadows? because i could never really get that right either

[digitalarena]

Hey, thanks for the reply. That is a great suggestion you have there, I will try that out too - don't know why I never thought of it.

My solution does not give soft shadows itself, merely pale shadows, so probably not much different to the shadow intensity you suggested.

However...

I have succeeded in getting soft shadows by using the "shadow buffer" mode in the EFFECTS tab of the Light properties.

The alternative is to tick the "enable soft shadows" box if you want to use Raytraced shadows. Though shadow buffer tends to render faster than raytraced soft shadows, raytraced is no doubt more accurate.

[rickei]

shadow buffer...i'll bet thats it.
does soft shadows work for you? I have seen 0% affect from "enable soft shadows", on a shadow catcher. but then again it's been a while since i tried.

I have always used DCG's Shaders Plus "GI shadow catcher" plugin for use with HDRI's and GI lighting. it works great!

[digitalarena]

This example uses a white shadow catcher.

The light source is a distant light, with a shadow intensity of 80 and 'shadow buffer' selected in the Effects tab (resolution = 1024, blur = 6, bias = 0.20).

The rendering mode was Photorealistic with 'Sky Light' selected.

The backdrop was just some random library footage. Backdrop had 'Interpolated' selected to make sure the downsampling from the original much higher resolution image was nice.

As you can see the soft shadows are visible on the shadow catcher using this technique.

[digitalarena]

This example uses raytraced shadows, ('enable soft shadows' was selected, light radius = 100.00 m, quality = good).

All other settings as previous example.

The key is to have a large enough light radius to create a soft shadow.

In life the softness is created by having a light source that is bigger than the object. This means light can creep round the object slightly creating a soft edge.

Does this help?

[Noviski]

I didn't know about change the color of shadows using the glow channel of the shadow catcher. Nice hint, digitalarena! Thanks!
About the intensity of the shadow, I allways select the light and drecrease the Shadow Intensity on the light properties tab.

Cheers!

[xav76]

thanks for the hint, definitely usefull!