Selection Feather does Smoothing instead

[gieffe]

In the first picture I clicked on "Select" -> "Feather..." but it seems the selection is instead smoothed. If I try "Select" -> "Smooth..." I obtain the same result.

On the other hand, if I go into "Refine", changing the "Feather" slides has the effect that I was looking for (see second picture).

Is this something intended to work this way and I'm doing something wrong or is it a bug?

I'm on macOS 11.4 and I'm using Affinity Photo 1.10.0

 

Thank you,

Giacomo

Edited September 5, 2021 by Giacomo Ferroni
Added OS and Photo versions

[NotMyFault]

It totally depends on what you want to achieve.

• Both Feather and Smooth actually smooth the selection, but in different ways
• feather does it by softening the transition between pixels select / not selected: a gradient transition. But in general it doesn’t touches the curvature of the selection edge.
• smooth is smoothing the edge curvature, but does not touches the gradient.
• Normally, you use relatively small radius for both, from fractional pixels to 10 or 25. 
• bigger radius radius settings are  possible, but then it starts to get very soft, and the effect of both could become difficult to distinguish.

When using them from within refine mode, you must consider that refine does additional magic, sometimes what you want, sometimes surprisingly or even counterproductive.

If you don’t know for sure: it is almost never a bug.

For someone like you who is new to Affinity Photo please start a thread under „questions“ to clarify. Here in the bug section you should be certain it is a bug, and provide evidence.

 

[gieffe]

Thanks for the response.

I'm aware of the difference between smooth and feather (I'm relatively new to Affinity Photo, but I've used Photoshop for many years).

However, I do think this is a bug because moving the feather slider (from "Select" -> "Feather...") does smooth the edge curvature instead of softening the transition between selection and non-selection. This doesn't happen from within Refine edges (regardless of the other magic things that happen behind).

Could you try replicate the steps I described in the first post?

[NotMyFault]

1 hour ago, gieffe said:

Could you try replicate the steps I described in the first post?

Unfortunately not.😔

There is a general challenge especially for long term photoshop users. Most functions in Photo are identical, but not all. Even if identical, the workflow / UI could differ totally to achieve the same result. Some later PS features are missing in Photo. 
I personally never used PS after 1.0, so I’m lacking the knowledge how current PS behaves. You may need to explain in more detail what you are expecting.

Could you please provide the required information according to the pinned post:

• example document where the issue is reproducible (saved with history)
• screen recording showing the actions to reproduce the issue
• include full Screen / Window, e.g. Layer Stack, Histogram, Info Panel, Channels Panel, Transform panel etc if possible

 https://forum.affinity.serif.com/index.php?/forum/71-bug-reporting/

As you issue deals with selections, please save (and rename) them as spare channel:

1. basic selection
2. Feathered by x px
3. refined and feathered by x px
4. include screenshots of all parameters used, similar to those of your original post

Edited September 6, 2021 by NotMyFault

[gieffe]

Sure, I’ll post a file and details requested ASAP. Thanks

[MEB]

Hi @gieffe,
Welcome to Affinity Forums
You are using a very large value for the Feather selection command (207,8px) whereas in the Refine Selection you set it to 37,2px thus you can't really compare their results directly.
Since the value you are using for the Feather selection command is high, the edges of the selection becomes quite transparent, shrinking and smoothing the selection marching ants because it only marks pixels with an opacity equal or above to 51% transparency.

If you start from the same shape rasterised, select it, feather the one on the left 150px and smooth the one on the right 150px, invert the selections and press delete you can see clearly the difference between the two. Below are the resulting selections (marching ants) after applying the feather and smooth commands (150px) and the second image on bottom shows the result of inverting and deleting the inverted selection for each.

 

Selections (marching ants) - feather and smooth set to 150px

 

After inverting and deleting each selection.
 

 

[gieffe]

Thanks @MEB, I tried what you suggested and in fact the behaviour is different between the two and it is what I was expecting  The visualisation of the marching ants mislead me. 

@NotMyFault I don't think we need to continue further with the file and detailed steps.