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I would like to render the volume that is shaded by an object (e.g. cube), not only the 2D shadow cast on the ground (as in the attached image).

I understand that in reality the shaded volume is not visible as shaded (only when it "reaches" a surface like the ground plane it becomes evident), but in my project I need to somehow show the shaded volume as well (preferably semi-transparently).

Is there an easy way to do it? I am using the lamp of type Sun and the Blender Render engine.

Shadow

flotr
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  • @someonewithpc thanks for the link, but it didn't help. It's related to the Spot lamp and/or Cycles. – flotr May 17 '15 at 18:44
  • @someonewithpc thanks again, but the link refers to the Spot lamp. I am using the Sun which does not support Halo :( – flotr May 17 '15 at 20:31
  • Further, it seems that the solutions refer to an inverse case, where there the light is limited (e.g. through a window). – flotr May 17 '15 at 20:32
  • Oh, ok I didn't realize that was what you wanted – someonewithpc May 17 '15 at 20:50
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    if you are not prepared to use a spot light, the only way is for you to create an image to superimpose over the image. Is there any reason you would not do the spotlight? – Robin Gething May 20 '15 at 06:37
  • No particular reason actually, except that the rays have to be parallel. However, on this small example it will not be noticed they aren't, so I will try with a spot light. – flotr May 21 '15 at 12:44
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    Possible duplicate: http://blender.stackexchange.com/q/6298/599 – gandalf3 Dec 05 '15 at 08:13
  • Do you want to be able to see the dark parts of the cube, but not the cube itself (like a smoky cube)? Or do you want to see something in the gap between the cube and the floor where the shadow is being cast (kind of like a god-ray)? – Matt Jul 08 '16 at 21:19
  • Most of the best solutions for this are going to require Cycles, because BI doesn't really know what light is, or where it's going, or what it's passing through... – Matt Jul 08 '16 at 21:20

2 Answers2

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Make a point cloud where you want your voluminous shadow to be (I suggest keeping it cubish in shape so everything matches up alright), and use the volume shader on this extra object instead of the surface shader. Making it a shadeless object would also keep it from casting any additional shadows (I don't think it does with the point cloud method, but this is a workaround if it does.). You can mix this whole thing with a transparent shader to control how visible it is.

EDIT: Point cloud is unnecessary with this method, just warp a cube to the right shape.

IncessantLee
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I'm not really sure what your asking and I didn't understand a thing IncessantLee said. But if you trying to ask how to only render the shadow and the cube casting the shadow but not the plane. select the plane, go to the materials tab, and under shadows check "shadows only". when you render it the plane will not be visible but you will still see the shadow and the cube. Hope this helps, again I wasn't really sure what you were asking.

Mason
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