Feathering/ Fading Edges

Post questions on how to use or achieve an effect in Inkscape.
eneuman93
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Joined: Fri Apr 27, 2012 6:10 am

Feathering/ Fading Edges

Postby eneuman93 » Fri Apr 27, 2012 6:12 am

Hello,
How can I make the edges of a star fade/feather along the shape of the star rather than in the shape of a circle or a line?
thanks
Edward

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brynn
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Re: Feathering/ Fading Edges

Postby brynn » Fri Apr 27, 2012 9:23 am

Image
Welcome Edward!

Try using Blur. You can access it in Object menu > Fill and Stroke. And actually it's a simple filter. There are many more complex filters which achieve various types and patterns of blurring, which you can find in Filters menu. There's even a Filter Editor, where you can tweak existing filters, or even make your own. But it sounds likea simple Blur will do what you want.

eneuman93
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Joined: Fri Apr 27, 2012 6:10 am

Re: Feathering/ Fading Edges

Postby eneuman93 » Fri Apr 27, 2012 12:26 pm

perfect! thank you! and thanks for the welcome:)

llogg
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Re: Feathering/ Fading Edges

Postby llogg » Fri Apr 27, 2012 1:18 pm

brynn,
I think the question is for something more refined than simple Gaussian blur.

eneuman,
There are three approaches I would take depending on the exact look you are after.
1. Take your shape, convert to path, duplicate. Select one path and apply blur (it helps to use a large number). Then select both paths and do Extensions>Generate from path>Interpolate with interpolate style selected. It might matter which order you select the paths so if you don't get what you want try reversing the order you've selected them.

2. Take your shape and duplicate it. Select one shape and apply blur (a significant amount but less than the above method will work). Move the blurred shape to the back. Align both shapes (non-blurred on top) and do Object>Clip>Set.

3. Take your shape, convert to path and duplicate it. Select one shape and ctrl-shift-drag to proportionally shrink around the original center of the shape. Select the larger path and open the fill and stroke dialog. Change the A value to 0. Select both paths and do Extensions>Generate from path>Interpolate with interpolate style selected.

In the attached image method 1 is the left and method 2 is the middle and method 3 the right. Note that the left image is affected by my settings for rendering quality. In reality the effect could be much smoother. Good luck.

Screenshot-1.png
Screenshot-1.png (170.69 KiB) Viewed 9237 times

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brynn
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Re: Feathering/ Fading Edges

Postby brynn » Fri Apr 27, 2012 2:18 pm

You're welcome, eneuman93 :D

Hi llogg,
I do know that feathering, in a raster graphics program is different from Inkscape's blur. But I thought that would be a good starting place, and if it wasn't quite right, the poster would say. I'm glad you posted though, because those are good techniques to think of in terms of traditional feathering :D

That 3rd option I find particularly nice, and would be perfect when trying to reproduce a photo. However, with hundreds or even thousands of tiny objects (my current project), Interpolate could bloat the file worse than all the blurs and gradients. ....I don't know though, if it eliminated the need for blurring entirely, I might have to try it. How many interpolation steps did you use for #3? Did you add any blur on top of the interpolation?

llogg
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Re: Feathering/ Fading Edges

Postby llogg » Fri Apr 27, 2012 8:55 pm

I think there were 20 steps of interpolation. I did not use any blur on top of it.

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brynn
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Re: Feathering/ Fading Edges

Postby brynn » Sat Apr 28, 2012 9:55 am

Thanks :D

llogg
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Re: Feathering/ Fading Edges

Postby llogg » Sat Apr 28, 2012 9:53 pm

If you want to feather in rather than out using method 3 works well if you simply apply a stroke with no fill to the original path, duplicate and shrink and apply a transparent stroke with no fill to the duplicate. Interpolate away.
Screenshot.png
Screenshot.png (145.84 KiB) Viewed 9155 times


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