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I am using Three.js to create graphical effects and cannon figure this one out. I am using the EffectComposer and adding either UnrealBloom or standard Bloom effect but the output is not as desired.

I know it is doing what it is supposed to but I am just wondering how to go about getting Bloom on specific objects only.

I tried rendering a different scene with it's own effect composer and superimposing the generated imagery using an additive blender but as you could imaging, the glow is degenerated and the object shows through objects that it should not.

I thought about using some sort of depth-buffer manipulation but was wondering if anyone has a better way of doing it.

The end result I would like is a normal looking scene but with a blue object this shines, giving a sci-fi type feel. Any help would be appreciated.

Patrick Sturm
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To get bloom, you need to have the objects to bloom be set to a brighter color than the rest of the scene, and have the bloom threshold set correctly.

That involves making sure that your overall lighting is dark enough so the whole scene doesn't get blown out...

Once you have the scene suitably dark, you can use BasicMaterials, or materials with emissive color set, to make the parts you want to bloom bright enough to cross the bloom threshhold.

manthrax
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  • Makes good sense but some parts of the scene will need to be reasonably bright in order to achieve realism, is this just not possible? Should I be designing scenes with this in mind or is there a better, not too expensive technique? – Patrick Sturm Mar 25 '18 at 01:29
  • Depends on you skill level. You could take the bloom effect shader and modify it to key off of some other parameter than brightness.. maybe a specific color like pure green or blue or something... – manthrax Mar 25 '18 at 07:34
  • Also, keep in mind you can layer effects and in different orders... so you could have a relatively dark scene, with your glowy bits set quite a brighter, then have the bloom pass on top of that, then have ANother pass that increases the overall brightness or saturation to change the "tone" of the resulting image. Making things look bright in CG is really more of an artful use of contrast, since displays aren't like real life. – manthrax Mar 25 '18 at 07:36