CURVEHUG drags a selection of objects along a curve, keeping them aligned to it, and drops them where you click. This is how you put manhole symbols along a drain run, tree symbols along a boundary, or arrows along a curved route — without rotating each one by hand.
What CurveHug does
Select anything — a symbol, a block, a group of geometry — then pick a curve. The objects follow the cursor along that curve, rotating to stay square to it as it bends, with live control over offset and rotation. Click to place.
The live controls while dragging:
+ or = — move further from the curve- or _ — move closer, and past it to the other side< or , — rotate 45° anticlockwise> or . — rotate 45° clockwiseO — type an exact offsetR — type an exact rotationM — toggle Multiple mode and keep placing
Enter, Space, E or right-click — finish
Offset and rotation persist for the whole AutoCAD session, so a run of symbols placed one after another keeps a consistent stand-off from the line.
How to use it
- Load the routine with
APPLOAD, or put it on your support file search path. - Type
CURVEHUG. - Select the objects to place.
- Pick the curve to follow.
- Drag along the curve. Adjust offset and rotation with the keys above.
- Click to place. Press
Mfirst if you want to keep placing more.
How it works
The preview is a temporary block, and that is what keeps it smooth. The selected objects are gathered into a single temporary block, and it is that one block reference which is dragged. Moving one object is far faster than moving fifty, which is the difference between a drag that tracks the cursor and one that stutters.
On placement the block is exploded back into its constituent objects and the temporary definition purged, so nothing of the mechanism is left in the drawing. You get the objects you selected, not a block wrapping them.
The curve may be nested inside a block or xref to any depth. When it is, a temporary top-level copy is made to align against and removed afterwards — the nested original is never touched. That matters because the curve you want to follow is very often inside an xrefed site plan.
Notes and limits
- Objects rotate to stay square to the curve. If you want them at a fixed angle instead, set a rotation with
Rand it holds. - Negative offset crosses to the other side of the curve — keep pressing
-past zero. - Offset and rotation persist for the session, which is deliberate for consistent runs, but worth resetting when you move to a different job.
- Multiple mode keeps you in the command; Enter, Space, E or right-click ends it.
Download and details
| Name | CurveHug — align and place objects along a curve |
| Download | CurveHug.lsp — 24.7 KB, plain AutoLISP source. Downloads directly; no zip to unpack. |
| Type | AutoCAD AutoLISP routine |
| Command | CURVEHUG |
| Requires | the ActiveX layer (loaded automatically by the routine with vl-load-com). |
| Source size | 24.7 KB, 563 lines |
| Error handling | Yes — a *error* handler restores every system variable it changed, on cancel as well as on error. |
| Undo | The whole operation is wrapped in a single undo group, so one U reverses all of it. |
| Compatibility | AutoCAD (any release with AutoLISP), BricsCAD, ZWCAD, GstarCAD, ProgeCAD and other IntelliCAD-based platforms. AutoCAD LT needs a LISP enabler. No .NET, no ObjectARX, no installer. |
| Author | YZ, August 2026 |
| Licence | Free to use, supplied “as is” with no warranty. |
References
- BLOCKNOTCH LISP — cut a clean gap in the line where each symbol sits
- COUNTARRAY LISP — array symbols while incrementing their numbers
- More free AutoLISP routines on this site
- Wisey’s Steel Shapes — free structural steel section drawing program