Author Topic: Soften Volume Material edges?  (Read 2004 times)

2017-05-30, 01:13:19

matsu

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Been trying to make some nice mist with the volume material. For the most part, it works the way I want it to. (Comparing the reference photo to my mockup scene. Pretty close.)

There is however one thing that is bugging me, and that is the hard edge of the vol mat that seems impossible to get rid of. (Look at the volumetrics element.)
The Boundary published this blog post where they use a displaced mesh to get a more blurred, or rather jagged, edge. That is one way of doing it, but a rather unpractical one for large scenes.
I have tried using falloff- and other maps. It works on simple objects, but not obejcts like the one in my scene. 

Is there some other way I have overlooked?

It would be great if the material had a "soften edges" checkbox - either tied to a distance from the edge, or a as value of pixels in the render.

And while we're on this topic: Do you think it would be possible to add a "clip fog object at camera position"-checkbox, so you'd never have to worry about your camera entering the volume object? (Either that, or just make it work even if the camera is inside the object.) :)

2017-05-30, 01:58:48
Reply #1

denisgo22

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+1 I Agree:)

2017-05-30, 18:01:16
Reply #2

romullus

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AFAIK this requires heterogenous volumetrics support to properly work. Planned for 1.7
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2017-05-30, 18:30:59
Reply #3

matsu

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Ah great! Looking forward to the update, then.

2017-05-31, 11:30:13
Reply #4

maru

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One (CRAZY) idea is to use falloff map with absorption and/or scattering. :)

2017-06-02, 14:50:21
Reply #5

matsu

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Tried that CRAZY idea, and it works as long as the mesh doesn't "self intersect" (from the camera POV). If it does, you get all these weird artefacts. (See attachment 1).

HOWEVER another totally crasy idea, is to use any map and set it to "Environ" instead "Texture". Then set the mapping to "Screen". In the example I used a gradient ramp, but I guess you could select a bitmap and in Photoshop, paint in the areas you wanted softened.

Actually, I had to try it out, so I added the one more pic. Smileyface indicates it works. :)

2017-06-02, 16:28:20
Reply #6

matsu

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Went back to my old scene and applied this method. It will not solve the hard edges that might appear "inside" the object, but it will take care of outer edge.
Attaching the volumetrics element for comparison.

A bit cumbersome, but worth it if you're working on a still image, I guess.

2017-06-02, 16:49:49
Reply #7

RolandB

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Very interesting topic on the use of the volumetric fog, thank you !
Your renders are wonderful !