How to Merge Shapes and Lines in Affinity Designer

Your lines and donuts each carry their own gray stroke, so wherever they overlap you get a gray edge cutting through the white. The fastest fix is to strip the stroke off each object, group them all, and add an Outline layer effect to the group so Affinity Designer draws one outline around the combined shape.

These steps are for Affinity Designer on desktop. On a Mac, use Cmd in place of Ctrl and Option in place of Alt.

How to merge lines and shapes with a group outline

1. Remove the outline from each object. Select each donut and set its Stroke to none so only the white fill is left. Give each line a white stroke at the thickness you want, with no gray on it.
2. Overlap the ends. Move or trim each line so its end sits inside the white ring of the donut it meets. If a line runs across the hole in the middle, the white will show there too.
3. Select everything. In the Layers panel, click the first line or donut, then Shift-click the last one so they're all selected.
4. Group them. Go to Layer > Group, or press Ctrl+G.
5. Open Layer Effects. With the group selected, click the fx button at the bottom of the Layers panel.
6. Turn on Outline. Tick Outline in the list on the left. Set the color to your gray, set Alignment to Outside, and drag Radius up to the stroke width you want.
7. Close the dialog. Close Layer Effects. You should now see one gray outline that wraps around the lines and donuts as a single shape, with the white flowing straight from one into the other.

Every object stays live inside the group, so you can still move a donut or reshape a line with the Node Tool and the outline follows. To add more lines later, drag them into the group in the Layers panel.

Any effect you put on the group, like a glow, also applies to the whole merged shape at once.

Merge them with the Shape Builder tool

If you'd rather end up with one real shape, use the Shape Builder Tool.

1. Select all the lines and donuts.
2. Pick the Shape Builder Tool from the toolbar.
3. Set it to the + (add) mode in the context toolbar.
4. Click and drag through the areas where each line overlaps a donut. Affinity joins them into one shape.
5. Give the merged shape your gray stroke.

Keep everything selected before you switch to the tool. If only some objects are selected, Shape Builder only works on those. This method flattens your objects, so save a copy of the layers first if you might want to change the layout later.

Merge them with Expand Stroke and Add

This is the classic boolean route. It turns everything into filled shapes and joins them.

1. Select the donut and go to Layer > Convert to Curves.
2. Select the donut and the line together.
3. Go to Layer > Expand Stroke so the line becomes a filled shape.
4. Click Add in the toolbar (also under Layer > Geometry > Add).
5. Give the merged shape your gray stroke.

To keep the parts editable, hold Alt while you click Add. That makes a compound instead of a flat shape. You can then move each part inside it, or expand the compound back into separate layers.

FAQ

Why does Shape Builder make my donut look thicker? After you expand the strokes, the white fill and the gray stroke are separate shapes. When you merge, the white area takes over part of the gray ring, so the donut's outline ends up a different weight from the line's. Putting the outline on the group avoids this because Affinity draws it once around the finished shape.

Can I still move the lines and donuts after I merge them? Yes, if you use the group and Outline method, since every object stays editable inside the group. With the boolean method, hold Alt when you click Add to make a compound instead of a single flattened shape.

How do I connect lines and donuts without drawing small white shapes on top? Overlap each line's end with the white part of the donut, group them all, and put an Outline layer effect on the group. The white of the line and the donut then join up on their own, and one gray outline wraps around both.