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Casting shadows without the object being visible

EyosEyos Posts: 114
edited December 1969 in Carrara Discussion

Hi,

I need my object to cast shadows, but I don't want it to appear in the rendered picture (as if it was completely transparent).
Can this be done?

Thanks.

Comments

  • HeadwaxHeadwax Posts: 9,987
    edited August 2012

    Not sure

    but Fenrik has a "toward/away' shader with which you can have different shaders on either side of a polygon. I guess you could make one side transparent?
    Put it in the alpha chanel and then invert.
    Maybe not,
    http://www.daz3d.com/shop/pose-and-shading-tools-2


    Also Inagoni has baker which will bake shadows onto a texture and let you export it - so the shadow will still be there even if object casting said shadow is not.

    http://www.inagoni.com/e107_plugins/content/content.php?content.3


    you can also put texture maps on lights
    so with some fiddling you could get the shadow on the texture map and project it

    also carrara has negative lights which with fiddling could emulate a shadow

    just depends what its the shadow of I guess

    Post edited by Headwax on
  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969

    I think maybe you're talking about a shadow catcher?

    Maybe if you describe a bit more what you're trying to do...cause it's not real clear what result you want to get. You can remove objects from your render in post (using an "object index" pass), leaving only their shadows, but I'm guessing that might not be what you really want.

  • PhilWPhilW Posts: 5,145
    edited December 1969

    If you are using a distant light, you could just move the object out of the field of view, and the shadow will stay the same size.

    But as has been said, you perhaps need to describe what you want to achieve in more detail, including what lighting you have in your scene.

  • tezentezen Posts: 0
    edited December 1969

    Hello Eyos!

    That´s an easy one:
    Just apply a black color / 0% to the Alpha-Channel to your "ghost"-object and
    put off "Light through Transparency" in the Rendering-Room-Tab.
    Voilá!

    Greetings
    tezen

  • HeadwaxHeadwax Posts: 9,987
    edited December 1969

    Heh, heh
    Live and learn eh? Nice idea tezen

  • tezentezen Posts: 0
    edited December 1969

    Hey Headwax!
    Live&Learn;? Sometimes... but mainly I`m waiting for earned money. Until that I`ll relax :D !
    Greetings tezen

  • PhilWPhilW Posts: 5,145
    edited December 1969

    tezen said:
    Hello Eyos!

    That´s an easy one:
    Just apply a black color / 0% to the Alpha-Channel to your "ghost"-object and
    put off "Light through Transparency" in the Rendering-Room-Tab.
    Voilá!

    Greetings
    tezen

    OK provided there is no other transparency in your scene.

  • tezentezen Posts: 0
    edited December 1969

    @PhilW: Of course! ...but with some compositing-work even that is possible.

  • PhilWPhilW Posts: 5,145
    edited December 1969

    Very true!

  • EyosEyos Posts: 114
    edited December 1969

    I appreciate all the ideas and suggestions. Thank you very much everybody.
    Eyos

  • JoeMamma2000JoeMamma2000 Posts: 2,615
    edited December 1969

    tezen said:
    @PhilW: Of course! ...but with some compositing-work even that is possible.

    ANYTHING is possible with some compositing work, but "fixing it in post" shouldn't be the goal. I'm still curious about the original intent. Something isn't quite adding up. I just hope he's not going roundabout for something he doesn't need to go roundabout on.

  • evilproducerevilproducer Posts: 9,050
    edited December 1969

    JoeMamma2000 said:
    I think maybe you're talking about a shadow catcher?

    Maybe if you describe a bit more what you're trying to do...cause it's not real clear what result you want to get. You can remove objects from your render in post (using an "object index" pass), leaving only their shadows, but I'm guessing that might not be what you really want.


    I agree, more information about the scene would help. I was thinking a shadow catcher as well, but they can also act as a mask. If there's an object in the scene that's behind it, or partially obscured by it, then it would be masked by it. Strangely, I used one once and mistakenly intersected the shadow catcher with a model (I was using it to mask the model I wanted it to appear later in an animation), and the model behind it was completely visible. Of course the alphas in the shader on the object may have confused Carrara as well.

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