Filter (Radial Blur) affecting the layer ABOVE it. Is this normal?

[Rustle]

Let me apologise in advance if I'm missing something obvious here. I cannot for the life of me work out why the top layer is being blurred by the Radial Blur below it.

You should see from the screenshot below that I have 4 layers (on a 6000x6000 pixel document):

1. Star shape
2. Radial Blur set to 180º
3. Rectangle shape
4. Rectangle background

What I'm expecting to see is layer 1 remain sharp, with layers 3 and 4 having the Radial Blur applied (though layer 4 won't be obvious, since I want to preserve the alpha).

One thing I have noticed, is that the edges of the CANVAS appear to be having an effect for some reason (not the underlying layer 4, as I can set that size to as extremely large and so that IT'S borders are well out of the way). In the second screenshot, at a Radial Blur of 31º, you can see the tips of the star being affected by the Radial Blur (preserve alpha removed for the purpose of the screenshot) and the soft edges of the layer 1 star begin to cover more of the shape.

(Note: I've tried this with both a transparent and non-transparent background)

What am I missing? I thought that layers affected things below them, not about them. What can I do to keep this top layer unaffected by the radial blur?

Kind regards, Russ.

[Ron P.]

Hi @Rustle,

In the Radial Blur dialog, in the upper-left corner, make sure the Preserve Alpha is enabled by checking the box to the left.

Also the Radial Blur Live filter will affect all layers beneath it, unless it is nested to one of the layers. If you are wanting the Blur applied to the bottom 2 layers, you could Group those layers, apply the Radial Blur to the Group.

 

[Rustle]

Hi Ron,

I've mentioned in my OP above that I have selected this (the first of the pics, it's selected). I've also de-selected it to show that example too in the second image.

Just to add further info to this, this evening I've tested every other blue filter, and only the Radial Blur causes this to happen.

Again, this is affecting the layers above the blur layer, so my expectation is that they shouldn't be affected at all.

Could this possibly be a bug?

Kind regards, Russell.

[R C-R]

Unlike Affinity Designer Affinity Photo always shows vector shapes as pixels after you draw them. I suspect that is what you are seeing & mistaking it as a blur at the star's edges.

If not, can you upload the file so we can see if we get any blurring?

[Ron P.]

Russell,

So far I'm not able to replicate the filter affecting the star layer. The Adjustment and Live Filter Layers always affect Layers below, unless they are nested in a layer, Group or otherwise. See Layer Drop Zones  and Using Live Filters

YouTube Videos:

Live Filters 101 (Technically Trent)

 

[Rustle]

Thanks both for your time on this. Honestly think I've found a bug.

Replicating it also seems dependent on the placement of the object being blurred too (the layers below). I'm experimenting with a few things here. Not easy to explain in words, so I may have to grab a screen capture.

[R C-R]

Just now, Rustle said:

so I may have to grab a screen capture.

Please just upload the *.afphoto file.

[Rustle]

Attached.

Defo looks like a bug to me.

If you drag the radial blue to different positions in the document, you can see it either affecting the star or not. Drag it closer to the seat, the star remains sharp. Drag it away, couple thousand pixels away perhaps, and the star is blurred.

RadialBlurTest.afphoto

[Ron P.]

Could be a bug..

Try Grouping the White and Black Rectangles, then apply the Blur filter to the Group. Also make sure the Blend Mode for the Group is set to Normal. The default is Passthrough, which blurs the star.

RadialBlurTest.afphoto

[R C-R]

4 minutes ago, Rustle said:

Defo looks like a bug to me.

Wow! There is something very weird about that file. Not only does the star look blurred, if I open it in Affinity Designer 2, the fan in my iMac starts spooling up (which it almost never does & if I select the star & try changing any of its properties the app begins lagging & showing radically different shape properties as I zoom in & out.

[Rustle]

Thanks Ron,

I've tried the things suggested and I still seem to be seeing the same issue.

Just about to his midnight here in the UK, so I'll be crashing out now and will pick up other replies tomorrow evening.

Thanks everyone.

[Rustle]

1 minute ago, R C-R said:

Wow! There is something very weird about that file. Not only does the star look blurred, if I open it in Affinity Designer 2, the fan in my iMac starts spooling up (which it almost never does & if I select the star & try changing any of its properties the app begins lagging & showing radically different shape properties as I zoom in & out.

Woah, that's crazy. I'm not seeing/hearing that here, though it does feel like quite the sluggish file compared to usual. It's 6000 x 6000 pixels, but that doesn't usually cause any issues with other projects.

[R C-R]

1 minute ago, Rustle said:

Woah, that's crazy. I'm not seeing/hearing that here, though it does feel like quite the sluggish file compared to usual. It's 6000 x 6000 pixels, but that doesn't usually cause any issues with other projects.

Something else I noticed with the test file is that the bottom rectangle is 6000x6000 px, the full size of the document,  but in the layer thumbnail it shows as though it is much smaller & offset from the center.

So I selected all 4 layers, copied to clipboard, & used File > New from Clipboard to get this RadialBlurTest copied.afphoto file. Note that in it the document size is much, much larger & all 4 layers are at the upper left.

I have no idea what's going on with the original but that new from clipboard version acts as expected -- the star is not blurred, just has the expected pixelated edges.

[Ron P.]

When I reconstruct @Rustle project from scratch I find:

• When the white rectangle is placed in the upper left and the star above it, using the same dimensions, the Star is blurred.
• Grouping the bottom 2 rectangles (white and black), applying the Radial Blur to the Group, the Star is still blurred.
• If I move the Star towards the Center, it no longer is affected by the Radial Blur. 😕
• Changing the Blend Mode on the Group from Passthrough to Normal, the Star is no longer affected by the Radial Blur.
  • This is true even on the Rustle's file.

 

[Ron P.]

To help understand what might be happening the AP Help states this about Blend Modes for Groups.

Quote

For a layer group, the default blend mode is 'Passthrough' (i.e. the group itself has no special blend properties of its own). This blend mode affects grouped layers in the following ways:

• If you have a filter in the group, the Passthrough blend mode will cause the filter to affect all other page content below it. If the group blend mode is changed to Normal, the filter's effect is restricted.
• For just an adjustment(s) in a group, Passthrough and any other blend mode will restrict the adjustment to just the group.
• If you have an adjustment above a fill layer in a group, the fill layer causes the adjustment to affect all other page content below it when blend mode is Passthrough.

I have not tried masking the Radial Blur filter from the Star. That's the only other way I can think of to avoid the star from being affected.

Edited:

Masking did not work.

[NotMyFault]

It’s 100% a bug. The filter affects the top star layer even if you have a fully opaque pixel layer between both.

Rendering is broken in 2.5.

see this report where a simple rectangle with inner stroke is not drawn correctly

 

[carl123]

This issue is relatively easy to recreate using just a Star shape (or any object) and a Live Radial Blur filter below it in the layer stack (no group)

We probably have not seen this issue before as it seems to need to have the origin of the Live Radial Blur Filter a fair distance away from an object for it to have a (negative) effect on it. Objects on the same canvas but nearer the origin can appear completely normal compared to those further away 

The issue occurs in V1 as well as V2

 

[NotMyFault]

The blur does not directly apply its regular effect. What we see is a rendering with 1/2 resolution. You can see the effect if you fill the shape with a pattern like 1px checkered board or ideally with Siemens star (to see the actual blur radius).
 

We get similar rendering bugs for other filters, I need to check my older posts where I have raised  similar bugs  (getting 1/2 resolution even with blur radius 0px).

[Rustle]

6 hours ago, carl123 said:

This issue is relatively easy to recreate using just a Star shape (or any object) and a Live Radial Blur filter below it in the layer stack (no group)

We probably have not seen this issue before as it seems to need to have the origin of the Live Radial Blur Filter a fair distance away from an object for it to have a (negative) effect on it. Objects on the same canvas but nearer the origin can appear completely normal compared to those further away 

The issue occurs in V1 as well as V2

 

Nailed it. This is what I was seeing when I was considering doing a screen cap.

Attached an extremely minimal screenshot. One object, one Radial Blur, then dragged the centre of the blue away, perhaps somewhere between 1500 - 2000 pixels away.

3 hours ago, NotMyFault said:

The blur does not directly apply its regular effect. What we see is a rendering with 1/2 resolution. You can see the effect if you fill the shape with a pattern like 1px checkered board or ideally with Siemens star (to see the actual blur radius).

Yes, this is the description you are looking for.

Thank you everyone for putting your precious time into looking at this with me. I'll find somewhere to report the bug.

 

EDIT: Just added the "bug" tag. Hope that's visible enough. For now I may have to continue designing and ignoring the issue, then flatten some layers go be able to remove the radial blur for the final output file.

[walt.farrell]

45 minutes ago, Rustle said:

EDIT: Just added the "bug" tag. Hope that's visible enough

Just so you know, that tag is not really meaningful. If/when this is acknowledged as a bug by the moderators they will tag it.

[Rustle]

Thanks Walt,

I've dropped them an email with a link to this thread. Mods are busy enough

[walt.farrell]

1 hour ago, Rustle said:

Thanks Walt,

I've dropped them an email with a link to this thread. Mods are busy enough

You don't need to do that, either. They'll get here.

[NathanC]

Hi @Rustle,

I can confirm i've replicated and logged this issue with the developers. 🙂

[Rustle]

Love this company. Thank you Nathan.