How to catch shadow of global illumination??

Eyos

I want to catch the global illumination with a shadow catcher.
Is there a way to do it?

cdordoni

Shaders Plus from DCG has a GI shadow catcher function. I haver not used it myself. Not sure if this will work for you, but you can check it out here: http://www.digitalcarversguild.com/plugin.php?ProductId=13

wetcircuit

cdordoni said:

Shaders Plus from DCG has a GI shadow catcher function. I haver not used it myself. Not sure if this will work for you, but you can check it out here: http://www.digitalcarversguild.com/plugin.php?ProductId=13

Shaders Plus is well worth the price. Adds all sorts of new Shader Trees to Carrara, and agree: the Shadow Catcher in it is a lot easier to work with than Carrara's shadow catcher...

stu sutcliffe

Thanks for reminding me I have got this!
Last week I was trying to render my dragon with GI and shadowcatcher,and it was awful! I could have sworn I had done it before. Now I know how I did it. I must have used this.....And it only took me half an hour to figure out how to reinstall. Now I probably won't need it for another year and forget again.

Eyos

holly wetcircuit said:

cdordoni said:

Shaders Plus from DCG has a GI shadow catcher function. I haver not used it myself. Not sure if this will work for you, but you can check it out here: http://www.digitalcarversguild.com/plugin.php?ProductId=13

Shaders Plus is well worth the price. Adds all sorts of new Shader Trees to Carrara, and agree: the Shadow Catcher in it is a lot easier to work with than Carrara's shadow catcher...

Thank you both. I have Shader Plus and it is really a wonderful plugin which I use a lot.
However, I tried to use it's GI Shadow Catcher module, but I could not achieve the results that I needed.

I manage to achieve good results using the following technique:

1) I used GI illumination - checked the sky light and indirect light check boxes. That way I got GI lighting on the objects in the scene, which gives realistic look.
2) I've put one bulb light above the scene and enabled soft shadows. But more importantly, I set its radius in the Effects tab to 15 cm. This way I've got wonderful blurry shadows beneath the objects - very similar in appearance to the ones produced by GI lighting. I also reduced the bulb brightness and shadow intensity to match my liking.
3) I've set the ground plane to regular Carrara Shadow catcher. The ground plane now catches the shadows coming form the bulb, and the objects are illuminated by GI light - so I now have what I need: GI lighting with a GI like shadows.

Additional benefit of this technique is rendering time: the single bulb + GI renders quickly, in comparison to other techniques that I tried like light domes.

Eyos

...Ah, one more thing: my current scene is small, so 15 cm bulb is OK to get the shadow effect.
I guess that for larger scenes this number should be considerably bigger.

wetcircuit

Eyos said:

...Ah, one more thing: my current scene is small, so 15 cm bulb is OK to get the shadow effect.
I guess that for larger scenes this number should be considerably bigger.

It also depends on what kind of light you use, Bulbs and spotlights can take small soft shadow settings, Distant lights need sometimes very large soft shadows, I think...

Fenric

holly wetcircuit said:

Eyos said:

...Ah, one more thing: my current scene is small, so 15 cm bulb is OK to get the shadow effect.
I guess that for larger scenes this number should be considerably bigger.

It also depends on what kind of light you use, Bulbs and spotlights can take small soft shadow settings, Distant lights need sometimes very large soft shadows, I think...

Yep. I'll often use 2 - 3 feet for a bulb light, and 50 - 100 feet for a distant or sun light