How to prevent elements in a group from showing through each other

[thedzko]

Greetings!

I'm here to propose the addition of an Affinity version of the Illustrator option called "Knockout Group" that prevents elements in a group from showing through each other, so that, even if two circles are transparent, if I put one at the top of the other, the one at the top will be at the top hiding what's beneath, like this:

Even though both circles are transparent, the green is still at the top and doesn't show the purple line that should be beneath.

With that option I can achieve this! The clock at the top is not showing what's beneath, instead, it's showing the background (which is transparent but this image shows a white color).

Thanks! If there's an option like this already, please tell me! I've been searching this with no luck, so I guessed that it's not actually on Affinity Designer!

 

[Pšenda]

Try Blend mode = Erase.

[GarryP]

Note: If you use Blend Mode = Erase, as suggested above, the layer(s) affected by the blend will be rasterised upon export. That may or may not be important to you but it’s worth knowing before you use it a lot and later find that you can’t export as you want to.

[Pšenda]

3 hours ago, GarryP said:

Note: If you use Blend Mode = Erase, as suggested above, the layer(s) affected by the blend will be rasterised upon export. That may or may not be important to you but it’s worth knowing before you use it a lot and later find that you can’t export as you want to.

And do you really think that the specific "Knockout Group" mode is transferable between all applications in vector form?

[G13RL]

One way to do it: copy the upper circle, "Divide" with the two circles, delete the two upper layers. Then paste the previously copied circle.

[GarryP]

1 hour ago, Pšenda said:

And do you really think that the specific "Knockout Group" mode is transferable between all applications in vector form?

Pardon?
All I did was tell people reading this thread that the Erase Blend Mode rasterised things.
It wasn’t meant as a critique of your suggestion, just a cautionary note for anyone wanting to try it.

[Pšenda]

But I'm just writing that "Knockout Group" is not exactly a standard blend mode (supported by all vector formats), so the OP certainly knows (or is not interested in it) that rasterization will occur during export.
As with Blend mode = Multiply, and many more.

Because the OP requires a "general" property/function, a specific example with circles may not help it in all situations, see the second case.

[thedzko]

On 2/11/2021 at 11:22 AM, Pšenda said:

But I'm just writing that "Knockout Group" is not exactly a standard blend mode (supported by all vector formats), so the OP certainly knows (or is not interested in it) that rasterization will occur during export.
As with Blend mode = Multiply, and many more.

Because the OP requires a "general" property/function, a specific example with circles may not help it in all situations, see the second case.

I've understood more about what I was trying to do, I was then learning about SVGs. 

The thing is that the "Knockout Group", while on the Illustrator, is a nondestructive option that, when exported as SVG, exports everything as you saw it on the app. With every part properly expanded/"booleaned" if necessary. 

So, using the icon I posted as an the example... 

The Erase blend mode does the trick on the app with the caveat of having to duplicate the clock's circle object in order for one to "knockout" what's behind and make it transparent. With Illustrator, you just need the clock's circle fill to be transparent, the stroke of the circle can be of any color and it would still be visible. 

On top of that. When you export it as SVG, it gets rasterized. So it was useless because my intention was to to copy the HTML code of the SVG. 

So, this can be resolved some possible ways, two of which are:

1. When exporting SVGs; there should be an option to disable rasterization when using the erase blend mode. That way, the resulting SVG is being "booleaned" automatically. 

2. Adding a similar option to Affinity Designer. Maybe an extension of the Erase blend mode. 

Considering 2.0 is already around the corner (or not) this isn't likely to be added. But at least the team should consider it for future updates. 

Thanks, guys. I actually went around the problem that year by using boolean operations. 

[loukash]

On 11/6/2022 at 9:25 AM, THEDZKO said:

on the Illustrator, is a nondestructive option

On 11/6/2022 at 9:25 AM, THEDZKO said:

I actually went around the problem that year by using boolean operations. 

There is a nondestructive workaround by using compound paths and duplicates of the shape that you want to knock out. Of course this will only be manageable with not too complex background objects, as e.g. groups cannot be part of a compound without losing individual attributes of each object within.

 

No idea how well this vector trickery translates on SVG export though…

More advanced "tricks" can be done using Symbols that have been appropriately "fine-tuned" using APh's "Links" feature, so that you wouldn't even have to select each knockout shape manually. I've posted a few of such experiments last year.