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What would be a way to create a glow in Blender. For that purpose I've been always using the compositor. However, that is pixels work, which means it is a 2d work. To make a 3d one, do I have to use particles, nodes or maybe some simulator? Because the compositor deals with images, which will make the glow to be out of perspective (flat). is there a way to make a glow with depth in Blender? Here is what I mean (If we assume that the blue color is a glow, it is clear that like other objects it is part of the perspective of the 3d view, which means that it has depth) -

enter image description here

And if possible, how to make one in cycles?

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  • $\begingroup$ Do you want volumetrics? $\endgroup$ – someonewithpc Sep 8 '14 at 16:25
  • $\begingroup$ I was about to update the post, sorry. What does volumetrics does anyway (never used it before)? $\endgroup$ – Vladimir Sep 8 '14 at 16:27
  • $\begingroup$ Basically .. fog. $\endgroup$ – someonewithpc Sep 8 '14 at 16:31
  • $\begingroup$ Thanks. Basically the kind of glow that fades out of the object, so maybe fog is not what I need. $\endgroup$ – Vladimir Sep 8 '14 at 16:35
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    $\begingroup$ This could be of use to you: blender.stackexchange.com/a/3640/3127 $\endgroup$ – GiantCowFilms Sep 8 '14 at 18:02
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Why would there be a glow around bright objects?

If the air is clean and transparent the light travels right through it, with no scattering and there is no glow around light sources or bright objects.

enter image description here

If there are particles floating in the air, those would get lit by the light source, light gets scattered, hence the perceived glow (think of a foggy night or the smog on a city)

With glass is the same thing: Clean and high quality glass would produce a non significant halo/glow around bright objects, the light would pass through it with very little dispersion. A dirty, scratched or humid glass would show the bright parts of an image with blurred edges caused by dispersion on the surface or the thickness of the glass itself (think a fogged or dirty window, or even a low quality or scratched camera lens)

So how do you create a glow then?

  • Option 1

    Using the compositor would give you the option of the dirty glass. You can expand the brightess of the bright pixels using a glow node on the rendered image.

    enter image description here

  • Option 2

    If you want an environment with suspended particles then you use volume scatter in your world.

    enter image description here

    Maybe a bit exaggerated but just to get the point across.

    enter image description here

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    $\begingroup$ @Vladimir Is it possible you could show an example of such a picture with a "non flat glow" (a "physically accurate" fantasy glow)? I still think the compositor is the way to go, as you have the most control there.. $\endgroup$ – gandalf3 Sep 9 '14 at 18:48
  • $\begingroup$ By "fantasy", I meant a glow that does not exist in the real world (Cegaton's example is a glow that occurs in real world, I think). By flat, I meant a glow that has depth like the image above in my post. The compositor deals with pixels. $\endgroup$ – Vladimir Sep 9 '14 at 18:57
  • $\begingroup$ @Gandalf3 And by "physically accurate" I meant the glow to have depth (not to be 2d, but 3d). I could just say "3d", but that's the word that came to my mind. The compositor, as we all know it, deals with images, which will make a glow that is out of perspective. That's why I posted the image above (the first one). $\endgroup$ – Vladimir Sep 9 '14 at 19:28
  • $\begingroup$ @Vladimir If by "3D blur" you mean a glow which gets smaller in the distance, even though the brightness of the light source remains the same, I'm not sure thats "psychically accurate" in terms of lens blooms.. $\endgroup$ – gandalf3 Sep 9 '14 at 19:54
  • $\begingroup$ Well, yeah but, what is some approach to create a glow effect other then composting (if there's any)? $\endgroup$ – Vladimir Sep 9 '14 at 20:06
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You can use volumetrics and procedural gradient textures to create a glow effect:

enter image description here

The setup:

enter image description here

This works by defining two spherical gradients which are infinitely long (making them cylindrical), and using those to create the hard white part and the soft colorful bit.

The gradients are defined in object coordinates, so they will stay with the object when it's animated. Note that because of this, the origin of your blade object will make a big difference. If it's centered it should be fine.

A third gradient is used to fade the cylinder gradients out before they get to the tip of the blade object. This will have to be configured depending on the length of your object and the location of it's origin. It should look something like this:

enter image description here

Provided that your origin is centered, all you should have to do is tweak the Z location value in the mapping node until the gradient is in the right place.

Note that your blade object should be a bit fatter than you might make it normally, as it has to contain the glow. Also note that it doesn't actually have to be a cylinder, as the cylindrical shape is defined in the material nodes.

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  • $\begingroup$ This is actually pretty much what I was looking for back when you answered my question (blender.stackexchange.com/a/3640/3127). Of course, back then, we didn't have volumetrics and I wasn't totally thinking of making it material-based instead of compositor-based. $\endgroup$ – kizlink Oct 13 '14 at 11:29
  • $\begingroup$ @kizlink Ha, I was thinking of that when I wrote this one.. Glad you found it :) $\endgroup$ – gandalf3 Oct 13 '14 at 20:26
  • $\begingroup$ Absolutely astonishing! The result looks hilarious ... yep, node tree is not that easy ;). Thanx for the .blend file so we could see the action - for sure I will use it in my WIP now! $\endgroup$ – Jan Matys Nov 21 '18 at 22:40
  • $\begingroup$ ...it could not be used for bent objects (only straight) so very limited usage - sadly. $\endgroup$ – Jan Matys Nov 28 '18 at 0:56
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Here's another option.

Create a plane and place it perpendicular to the camera and in front of it, that's going to act like a camera filter. (I like using the Create Camera Image Plane Addon to create a plane that always fills the frame and follows the camera using drivers)

enter image description here

Make the materials for the plane transparency and refraction.

enter image description here

enter image description here

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  • $\begingroup$ You should probably use a very thin cube instead of a plane, as everything on one side of the plane is being refracted, creating a rather large difference between the transparent shader and the refraction shader.. $\endgroup$ – gandalf3 Sep 9 '14 at 20:37
  • $\begingroup$ @gandalf3 I tried it but I don't see any difference... $\endgroup$ – cegaton Sep 9 '14 at 20:48
  • $\begingroup$ There is one: pasteall.org/pic/76799 $\endgroup$ – gandalf3 Sep 9 '14 at 21:00
  • $\begingroup$ @gandalf3 Ok got it :) $\endgroup$ – cegaton Sep 9 '14 at 21:02
  • $\begingroup$ Thanks. Looks a little weird to me, but can you make an update? How do you mean by a "filter". The nodes are for the sword like objects or for the plane(I've never used something like this before)? $\endgroup$ – Vladimir Sep 9 '14 at 21:52
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Here's a way to fake a glow in cycles:

Create an object and give it an emission shader.

Duplicate the object and resize it so it's slightly larger than the original (this will become the glow)

enter image description here

Create and assign new material for the glow object with the following nodes: a transparent material for the surface and Volume scatter for volume.

enter image description here

enter image description here

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  • $\begingroup$ Thanks. I get similar results with a "Layer weight" node, but this is better. $\endgroup$ – Vladimir Sep 9 '14 at 18:59
  • $\begingroup$ Thanks for the answer, it's just that there is no blurring. If I blur it in the compositor, it would be out of perspective. Any idea? $\endgroup$ – Vladimir Sep 9 '14 at 19:38

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