What a Pattern Produces
Every 3D pattern ends with one decision, and it is a single toggle in the popover: One body. Off, you get a body per copy. On, you get one fused solid. The geometry looks identical in the viewport and the difference shows up the moment you export.
Off: a body per copy
One body is off by default, and in that mode a pattern of N poses gives you N separate bodies.
The original stays exactly as it was. Each copy is an independent body named <Source name> (Copy N) after its source, and each one takes the next colour from the body palette. That palette holds 16 colours and then wraps, so in the 20-copy pattern this article keeps coming back to, copies 17 to 20 repeat the colours copies 1 to 4 already have.
Copies that touch stay two distinct bodies meeting at a shared face: nothing is fused. They will look welded and behave as separate parts everywhere it matters: in the body list, in a boolean, and in an export.
On: one solid
Turn One body on and the source body is replaced in place by a single genuine fused solid covering every pose. The seams between copies are unified away, so a row of overlapping bosses comes out as one continuous piece of material rather than five pieces stacked against each other.
Copies that do not touch still give you one document body, whose shape happens to be several disjoint solids. That is a legitimate state and it is what you want for a print plate: one body, several islands.
| Aspect | One body off |
One body on |
|---|---|---|
| Bodies in the document | N | 1 |
| Naming | <Source name> (Copy N) |
The source body, replaced |
| Colour | The next palette colour per copy, repeating every 16 | One colour |
| Touching copies | Distinct bodies meeting at a face | Fused, seams unified |
| Non-touching copies | Separate bodies | One body of disjoint solids |
| Cost | A real copy and a fresh mesh per copy | One shape shared across the poses, plus a fuse |
What this does to an export
STL writes one file per visible body. A 20-copy pattern with One body off downloads twenty STL files, staggered one after another, with the browser stopping to ask whether you really want multiple downloads. The same pattern with One body on downloads one.
STEP writes a single file either way. The difference is inside it: twenty solids or one.
Hiding bodies is a way to export a subset, and the two formats do not treat hidden bodies alike. STEP drops every hidden body; hide the copies you do not want and the file contains only what is left. STL drops hidden bodies too, with one exception: a body whose role is support is always written out, visible or not, because it is real printed material and the plate needs it.
Cost
The two modes do different amounts of work. With One body off, each copy is a real copy in the kernel and gets its own fresh mesh for display, so the cost grows with the count. With it on, one shape is shared across every pose and a fuse runs on top, which is cheaper overall even with the fuse.
If a large pattern has made the model sluggish, the toggle is the first thing to try.
Copies are ordinary bodies
Nothing about a copy is special. Once a pattern with One body off has run, you can hide a copy, recolour it, boolean it, move it or pattern it again, and none of that touches the original.
A body produced by one pattern is a valid source for another, deliberately. A mirror of a mirror gives you four quadrants and a linear pattern of a circular one gives you a row of rings. Build the unit, pattern it, then pattern the result.
What is not there
Four things people look for and will not find.
- No Explode or Materialise for a 3D pattern. That tool exists, but it belongs to sketch patterns only: see Patterns Inside a Sketch. A 3D pattern stays parametric. If you need one copy to differ, model it separately rather than trying to break the link.
- No pattern along a path. Directions are straight lines and circles.
- No per-instance suppression. You cannot skip copy 4 of 9.
- No scale between copies. Every copy is the same size as the source.
When it fails
If the pattern itself cannot rebuild, the step goes red and the popover shows Pattern failed to regenerate..
A partial failure is different and it does not stop anything. The step stays valid, turns yellow and names the copies it dropped: Pattern: copies 3, 5 failed and were skipped. You keep the copies that built. With One body on this matters more than it looks, because the fused result is missing those poses without the body count changing to tell you: check the numbers in the message rather than counting solids on screen.
See also
- Repeating a Body Along a Line: rows and grids, and the fields shared by all four tools
- Repeating a Body Around an Axis: rings and mirrors
- Working with Several Bodies: managing the bodies a pattern hands you
- Exporting Your Model: what each format writes out