No Self-Shadow

Hello Everyone

I’m trying to make a Node-Setup or something, what makes a Face with no
Shadows from his own geometry.
I mean: The face should only get shadows from other objects. Not from him self.

In this picture you see a shadow from a stick on suzannes face. But around that
shadow, there are a lot of shadows from suzannes faces it self.
I only want to see the shadow from the stick on suzannes face.

Anybody an idea? I need that for VFX…

Should be easy, I will give it a shot.

what set up did u use?
is this with cycles ?

I did a test and don’t see these shadows!

happy cl

Yes, this is in Cycles.

The setup on suzanne and on the stick is a simple Diffuse-Shader and nothing else.

The lamp i used is a Hemisphere.

Here, with this setup Suzanne will produce no shadow at all. But the downside is that even shadows casted by Suzanne on other objects will not be rendered either. It will require a more advanced setup else.

From my understanding these (arrow) are the parts the OP is fighting with:

The dark parts on Suzanne herself. The problem is that from my understanding these are not shadows in a pathtracing sense of the word. These are just “areas not being hit by light” in contrast to “areas being blocked from light by other geometry” (= shadow). That’s why no filter based on shadow rays can stop these darker areas from happening.

Left images: No self-shadowing, just “areas not being hit by light”,
Right images: Self-shadowing.

re done test with your set up and don’t get what you get
missing something here!

can you upload your file so we can check it out !

note :

Shadow: the ray is used for (transparent) shadows
so this is used when you have a transparent object !

just in case check this

happy bl

Yes, you do:

The OP seems to want the shadow from the plank on the monkey, but other than that a kind of shadeless material. No getting darker in the shade, no shadows from the eyebrows etc.

controlling on per object shadows!

Read the link about VFX
but still not certain it can be done

if u remove lamp shadow with multiple sample
you loose all shadows!

happy bl

Thank you all for you help :slight_smile:

Well: I did try the setup with the light path, but it has the same result, like i deselect the shadows
in the ray visibility in the object properties; there are still shadows in the face, from the face it self.

Here is the blend file for RickyBlender.
No_FaceShadow.blend (596 KB)

There would be an option using the Shadow pass on the compositor … but there’s weird black spots appearing on Suzanne even without Sadow ray visibility or the Light Path setup:

What are you trying to achieve? Maybe we can start from that and see if there are other ways to achieve the effect you want …

ok I see some differences
you set material as shadow transparent !
with lightpath it does not show the monkey shadow

but u still want to get rid of the shading on the object !

is this what you want ?

happy bl

With lightpath shadow, one indeed can get the shadow of the stick without the sharp shadow from suzanne herself. The fact that shadow in cycles is different from light just not hitting something is kind of an artifact, right? Because physically there is no difference between a shadow and light not hitting something. But on the other hand, stuff being visible yet casting no shadow is also unphysical, so I guess one cannot complain about the rules not broken in exactly the way one would want them to be broken.

Anyway, perhaps the OP can somewhat better explain the application, besides that it is needed for vfx. That way, we can perhaps come up with a trick.

O.k… i see, there is no “real” way to do, what i was hoping for. So i have to use the light in the scene
a little bit smarter.

My goal is, to eliminate the red market shadows like in this scene, where a robot wants to come in to my head :slight_smile:
But i still need the green market shadows.

In the end, here are useless shadows on my head. I thing, nobody can see it, (except you all, because you know these shadows are wrong)
But in other scenes, this could be a real problem, so i was hoping to solve it.

For now, i just make a smarter light setup in the scene.

THANK YOU ALL FOR YOUR HELP! It’s very nice from you all.

Can’t you render the shadows in Blender Internal and use a “shadow only” material for that?

Yes! Thanks IkariShinji, thats possible. I need to do a “Shadows only” Material and then deselect “Cast” in the same property. Thats working.
But i wished, there is a way direct in cycles.

Thank you :slight_smile:

Yeah, Cycles is desperately in need of a “shadow catcher” material for compositing, heck, even for product shots with an “endless” background. Well, maybe next release…:wink:

I’m not sure DingTo is aware of this urgent need, it seems like something he could whip up.

A shadow catcher has been asked for ever since Cycles was introduced, but is - from my understanding - quite tricky to do in a pathtracing engine, as shadows are properties of the objects casting them, not of the objects they are cast on.

Well, actually, shadows are physically speaking not really a property, right? They are just the absense of light. But I get your point. What I don’t understand however, is that the light path node does have a shadow ray output. How/why does that work then?

Anyway, I guess the conclusion is that there are still some aspect where bi rules.