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Ok, I am creating tiny particles (there won't be a ton so doing it manually) to achieve a kind of effect like this per this question: Sun Glow Particles

However this, and in my situation, the transparent material Ive created (with just a transparent BDSF and emissive shader mixed) has a hard edge. This doesnt get the desired, soft particle effect I want:

enter image description here

I want something where the edges of the "particle" meshes are blurred in some places, like if you took a Photoshop brush and erased some parts. I tried volume scatter as suggested but Id like to just make particle meshes.

Is this SOFT bokeh material possible?

What I did:

enter image description here

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    $\begingroup$ I guess there are several solutions, you could play with the blur in the Compositing, or the Depth of Field of your camera, or play with the material of the dust: make transparent bubbles with a Fresnel to blur the edges... $\endgroup$ – moonboots Jul 9 '18 at 21:38
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    $\begingroup$ That looks like Bokeh blur and is most often achieved in post production, or using depth of field while rendering. You can probably fake it in 3D using some sort of circular texture $\endgroup$ – Duarte Farrajota Ramos Jul 10 '18 at 0:28
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To truly get transparent edges you would need to move to volumetrics and vary the density or emission based on the proximity to the surface. This can be achieved using the OSL shader described here and produces the following result :

nodes and result

You can vary the 'depth' by adjusting the Multiply node - or replace that and the Color Ramp with your own calculation.

Note that this method will be way less efficient for rendering since it's using volumetrics - and this is further compounded by using OSL which is not GPU compatible (so you'll have to render with CPU).

Using volumetric scatter/absorption as you would for smoke can produce the following :

scatter/absorb

Adjusting the Multiply and Power nodes affects the sharpness of the objects. You could also add a noise texture to vary the depth of the fade to make the edges appear more 'fluffy'.

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You can bevel the edges, or apply a subsurf and then use additional edges to control the round off, or a procedural texture that shows "worn edges". There's a free CG Masters tutorial that shows one of the many ways to do this. Here is the relevant node group from the tutorial worn edges. You can download the blend file from the tutorial page.

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  • $\begingroup$ See my edit - I came close but the transparent part, no matter the color ramp, still wont go all the way transparent $\endgroup$ – skyguy Jul 10 '18 at 10:18
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If you render the particles to another layer, in the compositor, you can use a blur/bokeh effect in combination with a transparency effect to get what you're looking for.

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