To preserve existing rounded corners, flatten live corner effects into path geometry before using Path → Combine. To keep rounding adjustable, combine the base paths first, then add Corners (Fillet/Chamfer) to the result.

This guide covers making one compound path from original abstract shapes in Inkscape on a Mac. The steps use menu commands so you can follow them without translating keyboard shortcuts. The key decision is whether you need to preserve the visible curves or retain controls for changing their rounding later.

Choose what the combined object needs to do

Inkscape distinguishes a compound path from a group and a merged outline. A compound path can contain disconnected subpaths: making them one object does not connect their endpoints. The official Advanced tutorial explains this distinction.

Desired result Construction to use Editing boundary
Several objects that move together Object → Group Objects remain separate within the group
One path containing the existing contours Path → Combine Contours become subpaths of one object
One merged silhouette from overlapping shapes Path → Union Overlapping outlines are replaced by the combined outline

The Grouping Objects guide documents grouping as a way to manipulate several objects together. The Boolean Operations guide describes Combine as keeping all parts in one object, while Union keeps their common outline.

For example, two rounded tiles separated by a gap can become one compound path without losing that gap. Two overlapping tiles intended to become a continuous silhouette call for a different operation. Decide which result you need before converting the originals.

Identify how the corners were rounded

Rounded appearance can come from three different constructions. Inspect one object at a time before choosing the preservation method.

Rectangle rounding: Select the rectangle with the Rectangle tool. Its circular handles and the Rx and Ry fields control rounding. These controls affect all four corners together; they do not independently round one corner. See Squares and Rectangles.

Live corner rounding: Select the object and open Path → Path Effects. An entry named Corners (Fillet/Chamfer) means the curves are generated by a live path effect. Inkscape retains the original path so you can adjust it and have the effect update. See Live Path Effects.

Stroke rounding: Open Object → Fill and Stroke and inspect Stroke Style. Joins and caps change the stroke’s appearance independently of its fill. A rounded stroke join should not be treated as evidence that the underlying filled contour has rounded geometry. See Strokes.

This inspection avoids an unnecessary conversion. If the corners are already ordinary curves, there is no live corner effect to flatten. If you only need the objects to move together, grouping may finish the task while preserving their separate construction controls.

Preserve existing live corners before combining

Use this workflow when your shapes already look correct and retaining their current curves matters more than keeping the corner-effect settings.

Keep an editable original

Save a separate SVG copy before conversion, then work on the copy. This gives you a clear return point for changing the original rounding later.

Flattening is a construction boundary: the rounded result becomes geometry instead of remaining controlled by the flattened effect. Ordinary node editing remains available, but the original effect parameters are no longer the means of adjusting those curves.

Flatten each object's effect stack

  1. Select one rounded object.
  2. Open Path → Path Effects.
  3. Open the context menu beside its Corners (Fillet/Chamfer) entry.
  4. Choose Flatten.
  5. Repeat for the other objects before selecting them together.

The official Inkscape 1.3 release notes document exactly what this command applies: Flatten converts the effect stack from its beginning through the selected effect into the object’s geometry. Effects later in the stack remain live.

For a simple object with only the corner effect, flattening that entry completes the conversion. If several effects contribute to the appearance you need to preserve, inspect their order. Flatten through the final relevant effect when you want the whole visible result committed to geometry. Do not assume flattening an earlier entry also applies later effects.

Use Flatten from the effect’s own context menu here. The same release notes also describe a separate operation named Flatten in the Path menu; that is a different construction command.

Combine and inspect

Select the converted objects with the Selector tool, then choose Path → Combine. This creates the compound path. The documented operation keeps its constituent parts rather than merging them into a new silhouette. See Boolean Operations.

Switch to the Node tool and inspect the rounded sections. You can adjust ordinary curves using their nodes and handles; moving a handle changes its adjacent segment. See Editing Paths with the Node Tool. Compare the result with your saved original before continuing to reshape it.

Keep corners adjustable by combining first

For a new construction, another useful order is to assemble the base geometry first and apply rounding afterward. This avoids needing to carry separate corner-effect setups through the combination.

  1. Create the base shapes without rounding.
  2. Select any geometric shapes and choose Path → Object to Path.
  3. Select the resulting paths and choose Path → Combine.
  4. Open Path → Path Effects.
  5. Search for and select Corners (Fillet/Chamfer).
  6. Use the effect’s controls or on-canvas handles to adjust the corners.

The conversion in step 2 removes shape-specific editing controls. A rectangle becomes a path rather than retaining its rectangle controls. The manual documents the conversion under Editing Nodes on a Geometrical Shape. Keep a copy first if those controls will still be useful.

The manual’s Live Path Effects guide documents adding effects through the search field and adjusting individual corners with the Node tool. Leave the effect live while refining the construction. The 1.3 release notes also record the change to small triangular corner handles, so older instructions describing their appearance may differ.

Try a two-tile construction

As an illustrative exercise, draw one horizontal rectangle measuring 100 × 60 px and a second measuring 60 × 40 px. Leave a visible gap between them. These dimensions are sample inputs, not requirements; the Rectangle toolbar provides W, H and unit controls. See Squares and Rectangles.

Convert both to paths, combine them, then add the corner effect. Round one corner gently and another more strongly using their effect handles. Your target is one selectable object containing two separated, rounded contours, with rounding still adjustable through the live effect.

This example provides a practical decision test: if you need adjustable rounding on the assembled object, stop here. If you need its visible result as ordinary path geometry, save the editable version and flatten the effect on a working copy.

Handle rounded rectangles without a live effect

A rectangle rounded with Rx and Ry follows a simpler route: finish its rounding, preserve an original copy, use Path → Object to Path, then combine the converted paths.

The official Advanced tutorial states that converting a shape to a path preserves its appearance while removing capabilities specific to its original type. The rounded contour remains editable as nodes, but the rectangle’s radius controls no longer govern it.

Do not apply a second rounding effect merely because those rectangle handles disappear. First inspect the converted contour. Losing a shape-specific control and losing the visible curve are different outcomes.

Diagnose a result that looks wrong

A corner changes during combination: Return to the separate originals and inspect their live effects. Use the flatten-first workflow when preserving their existing appearance is the priority. The documented flattening boundary gives you an explicit conversion step instead of relying on separate live setups surviving a structural edit.

Colors change: A compound path has one fill and stroke. The Advanced tutorial states that combining uses the style of the lowest object in the stacking order. If separate colors are part of the design, keep the objects grouped.

An overlap becomes a hole: The same tutorial describes holes appearing when filled paths overlap after combination. If your intended result is a solid merged silhouette, reassess whether Union is the appropriate operation.

Only the border looks rounded: Recheck the join and cap settings in Stroke Style. The Strokes guide documents these as stroke controls. For a rounded filled contour, use rectangle rounding or actual curved path geometry.

The pieces remain disconnected: That is compatible with a compound path. Combining is not endpoint joining. Keep that distinction in mind when checking whether you have completed the intended construction.

Choose the operation order around the edit you expect to make next. Flatten existing corner effects before combining when their current curves are the finished geometry; combine base paths before adding rounding when you want continued corner adjustment. Keep the editable source alongside the converted result so later revisions have a clear starting point.

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