Repeating a Body Around an Axis
Use a circular pattern to lay copies of a body around an axis: spokes on a hub, lugs on a flange, feet under a round base. Select the body, pick Circular pattern (3D), choose the axis, and set how many copies across how much angle. Mirror (3D) is the other half of this article: it makes one reflected copy across a plane.
A body, not a face
Both tools follow the same rule as the rest of the family. They appear only when at least one body is selected, and a face does not count. Double-click the solid in the viewport, or set the Select tool's filter to Select bodies, and the tools appear on the toolbar. With a face selected they are absent rather than disabled, so there is nothing to click and nothing to explain the absence. Repeating a Body Along a Line covers the selection gesture in full.
The default ring of six is a ring of five
A circular pattern arrives with axis Z, Total angle 360 and Count 6, and that combination does not give you six spokes.
The pattern steps by totalAngle / (count - 1), so the last copy lands exactly on the total angle. With 360° and a count of 6 the step is 72° and the sixth copy sits at 360°, which is the same place as the original. You get five visible positions with two solids stacked at one of them.
Two ways to fix it, and both are correct:
- Count
N + 1. Leave the angle at 360 and ask for seven copies to get a ring of six. - Angle
360 x (N - 1) / N. Keep the count at N and stop the sweep one step short: 300° for six, 315° for eight, 324° for ten.
None of this applies inside a sketch. A 2D circular pattern divides the total angle by the count rather than by count - 1, so its default of six copies over 360° is already an even ring and needs no correction: Patterns Inside a Sketch has that arithmetic.
There is no reverse toggle for a circular pattern, unlike the signed spacing on a linear one. A total angle outside (0°, 360°] is refused, so to run the copies the other way, pick the axis the other way round.
Choosing the axis
The axis picker takes an edge, a reference axis or a world axis, and never a cylindrical face. You cannot click the inside of a hole and pattern around the hole's own centreline: build a reference axis on that centreline first, then pick it. Reference Axes and Points has the gesture.
World Z is the default, which is right whenever your part lies flat on the XY plane and wrong as soon as it does not.
If the axis cannot be worked out at rebuild time you get:
3D pattern axis could not be resolved
That means the edge you picked is no longer there: a step earlier in the timeline changed the geometry it came from. Reopen the pattern and pick the axis again.
Mirror (3D)
A mirror is the simplest tool in the family and the one with the fewest fields. It has no plane at all until you pick one, and no numbers: only the plane and the One body toggle.
The plane picker takes a planar face, a reference plane or a world plane. Unlike the circular axis, a face is exactly what it wants here, as long as the face is flat.
What comes out is one reflected copy, with the original left where it was.
Four things called Mirror
The word appears in four places in the editor and they do four different things. Picking the wrong one is a quiet mistake, because each of them produces a plausible-looking result.
| Tool | Where it lives | What it does |
|---|---|---|
Mirror |
The sketch toolbar's PATTERNS group | Reflects sketch geometry across a line, inside the sketch. No solid involved |
Mirror (3D) |
The pattern tools | Keeps the original body and adds a reflected copy |
Mirror across a plane |
A Transform positioning step | Reflects the body in place. No new body |
Mirror body |
Its own timeline step | Also reflects in place |
The first one is a different level of the model: it repeats curves before there is anything solid to repeat, and Patterns Inside a Sketch covers it. Among the other three the test is whether you want one body or two. If you need a left half and a right half, use Mirror (3D). If you have a left-handed part and need it right-handed instead, use one of the last two. The Transform popover carries the same warning as above: Mirroring flips handedness: threads and text come out reversed.
Transform Basics covers the positioning-step version.
When it fails
The refusals are shared across all four 3D pattern tools:
3D pattern requires at least one source feature
3D pattern count must be at least 2
3D pattern axis could not be resolved
A source feature of this 3D pattern was deleted
A partial failure is not an error. If some copies cannot be built, the step stays valid and turns yellow with a note naming the ones that were skipped, such as Pattern: copies 3, 5 failed and were skipped. Those numbers are copy indices counted round from the original, and they name the poses the kernel could not build; every other copy is in the document. A whole-pattern failure shows Pattern failed to regenerate. instead.
The timeline names these steps Circular pattern 1 and Mirror pattern 1, in creation order.
See also
- Repeating a Body Along a Line: rows, grids and the fields they share with this one
- What a Pattern Produces: whether you get separate bodies or one fused solid
- Transform Basics: the mirror that moves a body instead of copying it
- Reference Planes: building the plane a mirror needs