Erase Along Edge

Content ID:1800143

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Flatting Eraser that uses a reference layer to avoid crossing edges (see page for tips)

Clip Studio Paint lets you use a reference layer to see edges and only paint on one side of the edge. This tool uses this for cleaning up color layers!

I've been playing around with various fills and flatting tools and I thought it might be both more controllable and more enjoyable to erase using a reference layer than color with it.

This eraser in included among my flatting tools in my Tapioca Digital Painting Brush Set you can find in my gumroad store.

But this is a basic feature. Anyone can make this brush by just enabling [Do not cross lines of reference layer] and setting some basic settings.

  1. Select the lineart layer.
  2. Press the lighthouse button to set it as a reference layer.
  3. Then you can select your color layer and use the erase tool. It will use the reference layer to judge where the edge is.

Why or when should I erase this way?
Clip Studio Paint gives you different tools to do flats, fix colors or erase coloring mistakes. When one tool fails because of how the lines or edges or existing colors or layers are set up, you can have other tools you can rely on to still give you some convenience and control.

This tool takes advantage of Clip Studio Paint's brushes' "Anti-Overflow" feature which uses edge detection to paint (or in this case, erase) only one side of an edge.

If you use this anti-overflow feature as a flatting brush, you can end up with flats that are full of holes that you have to take care of later. The more complicated the inner lines are, the worse this method is.

If you just paint a blob and then erase the outer edges instead, you avoid the inner holes. Depending on the shape, it can be easier to erase like this.

If there are also outer intersecting lines, you may still have to erase them manually. If there are a lot of complex outer lines, this may not even be the best eraser to use. But for things like overall flats, especially in the first stages, this can save a lot of time.

You can erase the parts where you know are closed with a bigger radius, or use a smaller radius to erase carefully but still have the added benefit of avoiding the edges where it can.

This is especially useful for sketches (and rough animation) where your lines aren't necessarily closed but you still want to quickly and roughly give them a fill.

With the right hotkeys, you can easily switch between this and other erasers and flatting tools to quickly adapt to different cases. This eraser is something I pull out quite often when I just quickly need to change, edit and clean up small section of a coloring layer. I imagine it has saved me a lot of time already since I made it a few weeks ago.

In some cases, there are better and faster fill/flatting tools for cases like this like [Enclose and Fill]. But sometimes, the eraser is what you need. Using different tools will give you something to fall back to in case one of them doesn't work well for the situation.

Clip Studio Paint's edge detection isn't antialiased so your erased edges can end up very jagged. This isn't a big problem if you work at high resolutions or your lines are fully opaque. But if you only work at 100%, you may need to apply Filter>Blur>[Smoothing] or a slight gaussian blur to remove some of the roughness.


How does its edge detection work?
You can enable this edge detection feature in most brushes. The checkbox is labeled [Do not cross lines of reference layer] in CSP 1.10. If you don't see this option, you may need to enable it in the [Sub Tool Detail] window.

The edge detection works like a mini paint bucket tool, confined to the radius of the brush. It starts checking for the edge from the center and stops when it sees an edge or the radius of the brush, then limits its effect there.

If the edge is not complete within the radius of the circle, the effect of the brush goes around to the other side of the edge.

Sometimes, if the edge is transparent or light enough, it will be counted as a gap. In this case, the effect of the brush will still go around the other side of the edge as if there is a gap where the line was very light.

To change this threshold, you can adjust [Color margin]. Set it to zero (0) if you want it to stop at even the lightest lines as part of the edge.

[Area scaling] pushes the effect past the edge by the number of pixels you set. This is useful so the color can go under the lines and any softness, texture or antialiasing that it has. 1 or 2 can be enough but in some cases, 5 or 10 may be required.

The three [Scaling modes] determine how it extends the pixels, which is most noticeable either on corners or textures.
  • [Rectangle] expands at the corners as a box.
  • [Round] expands at corners as a circle.
  • [To darkest pixel] tries to expand by the maximum area scaling but still stops when it detects that the pixel has become its darkest/most opaque. This can be useful if the lines or edge has variable softness or thickness, but sometimes the fill can also look incomplete.

If the edges look wrong, try experimenting with different settings.

If you want to see where the center of the circle is, you can change the cursor type in Clip Studio Paint's [Preferences...] under Cursor>Shape of Cursor.
"Brush size and cross" will show the radius of the brush as a circle, and a small cross in the center.


Thanks for your support!
You can visit my store for hundreds of other brushes! - @PharanBrush

Content ID:1800143

Published : 3 years ago

Last updated : 2 years ago

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Check my Ko-fi shop or Gumroad store for my Clip Studio Paint brush packs!