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POINTBRIDGE LISP: Convert Point Data, Drawing to File

POINTBRIDGE reads coordinates from one place and writes them to another. Both ends can be any of five things: block insertion points, a text or CSV file, AutoCAD point objects, lightweight polyline vertices, or 3D polyline vertices.

What PointBridge does

So one command covers every combination of the five. Import a surveyor’s CSV as blocks on a chosen layer, at a chosen scale and rotation. Export every manhole block’s position for the setting-out engineer. Turn a scatter of point objects into a polyline through them. Pull the vertices of a boundary polyline out to a spreadsheet. Convert a 3D polyline to a lightweight one, or the reverse.

Attributes travel with the points. When both ends are a block or a file, attribute values are carried across. Export attributed blocks and each row gets the coordinates followed by that block’s attribute values; import the same file and the values are written back into the inserted blocks, in order. That is what turns a coordinate list into a real survey exchange — point number, description and level ride along with the position.

How to use it

  1. Load the routine with APPLOAD, or put it on your support file search path.
  2. Type POINTBRIDGE.
  3. Choose the input type and the output type. Whichever you pick at one end is removed from the list at the other.
  4. Use the Format button to say which file column holds which coordinate, and set the delimiter.
  5. Sort by X, Y or Z if the output needs to be ordered.
  6. Type POINTRESET to clear the remembered settings.

How it works

File columns are not assumed to be X, Y, Z. The Format button sets which column holds which coordinate, so a file arriving as Easting, Northing, Level — or as Y, X, Z — is read correctly without editing it first. The same setting controls the order columns are written in.

Delimiters: point, comma, semicolon, tab and space are offered, plus a free-text box for anything else. A .CSV file forces the comma and locks the control, so a file with a .csv extension is always genuinely comma-separated.

Sorting reorders attribute values with the points, so the pairing is never broken. Sorting by Y is how a scattered point file becomes an orderly chainage list.

The input and output types are always different — whichever is chosen at one end is removed from the list at the other, because converting something to itself is not a useful operation.

Notes and limits

  • Writing to an existing file replaces it. The file browser asks before overwriting.
  • Set the column format before importing an unfamiliar file. Easting/Northing order is the usual trap.
  • Attributes only travel between blocks and files, since points and polyline vertices have nothing to carry them.
  • Settings last the session. POINTRESET puts them back to defaults.

Download and details

NamePointBridge — move point data between the drawing and a file, in any direction
DownloadPointBridge.lsp — 71.9 KB, plain AutoLISP source. Downloads directly; no zip to unpack.
TypeAutoCAD AutoLISP routine
CommandsPOINTBRIDGE, POINTRESET
Requiresthe ActiveX layer (loaded automatically by the routine with vl-load-com); nothing extra — the dialog is written to a temporary file at run time and deleted again, so there is no .dcl to install.
Source size71.9 KB, 1,498 lines
Error handlingYes — a *error* handler restores every system variable it changed, on cancel as well as on error.
UndoNot needed — this routine only reads the drawing and changes nothing.
CompatibilityAutoCAD (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.
AuthorYZ, August 2026
LicenceFree to use, supplied “as is” with no warranty.

References