PARTWEIGHT works out what a cut plate part will weigh: select its outline, give a thickness and a material, and it reports the area, the volume and the weight. Select several outlines and it totals them.
What PartWeight does
This is the number that goes on a cutting list, prices a job, and decides whether two people can lift it.
The area is measured straight off the geometry you have already drawn. Typing the area in means working it out somewhere else first, which is both the slow part and the part that goes wrong.
Holes are handled the way a fabricator thinks about them: select the outline first, then the holes, and the holes are subtracted. A plate with a big central opening weighs what is left, not what it started as.
How to use it
- Load the routine with
APPLOAD, or put it on your support file search path. - Type
PARTWEIGHT. - Select the outline first.
- Then select the holes and cut-outs — they are subtracted.
- Give the thickness and material, and say whether the drawing is in inches or millimetres.
How it works
Units are asked for and the rest follows. Inches give area in square inches and weight in pounds; millimetres give square millimetres and kilograms.
Densities are held once, in pounds per cubic inch, and converted for metric by the exact factor 27.6799 — how many grams per cubic centimetre there are in a pound per cubic inch.
Holding one table and converting is what stops the two sets of figures drifting apart. Two hand-maintained tables agree on the day they are written and not for long after.
Notes and limits
- Select the outline before the holes. The order is what tells them apart.
- Outlines must be closed for an area to mean anything — see QuickTally for what an unclosed boundary reports.
- Tell it the right units. The drawing does not say, and the answer is wrong by a factor of thousands if you guess.
- It only reads the drawing, so there is nothing to undo.
Download and details
| Name | PartWeight — weigh a flat part from the outline you have already drawn |
| Download | PartWeight.lsp — 12.4 KB, plain AutoLISP source. Downloads directly; no zip to unpack. |
| Type | AutoCAD AutoLISP routine |
| Command | PARTWEIGHT |
| Requires | the ActiveX layer (loaded automatically by the routine with vl-load-com). |
| Source size | 12.4 KB, 288 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
- TALLYAREA LISP — area totals, and why an open boundary still reports one
- SUMAREA LISP — a live area total with holes subtracted
- Wisey’s Steel Shapes — section profiles to published dimensions
- More free AutoLISP routines on this site
- Wisey’s Steel Shapes — free structural steel section drawing program