AutoLISP Routines

HPGLIN turns a plot file back into geometry. HPGL — Hewlett Packard Graphics Language — is what a drawing became when it was sent to a pen plotter, and a great many drawings survive only as .plt files because the original DWG was lost, was on a machine long gone, or was never handed over. What HpglImport does What comes back is polylines, not the … [Read more...] about HPGLIN LISP: Read an HPGL Plot File Back Into AutoCAD

HOUSESHELL builds the outside of a simple house as 3D faces: floor, four walls, the eave soffits, the fascia, and a roof that is either gabled or hipped. What HouseShell does It is a massing model, not a set of construction drawings — the thing you want for a site study, a shadow test, a streetscape, or a quick view to show a client the shape of a … [Read more...] about HOUSESHELL LISP: Build a 3D House Shell, Gable or Hip

GRIDSNAP rounds the coordinates of things already drawn to the nearest multiple of a spacing you give. Snap mode only helps while you are drawing; this is for a drawing that has already gone astray — traced-over scans, imported DXF from a package with different tolerances, or work done with snap off where everything is a thousandth out and nothing quite meets. What … [Read more...] about GRIDSNAP LISP: Pull Existing Geometry Onto a Grid

GRIDREF lays a labelled Easting/Northing grid over whatever a layout viewport is showing: a border round the visible area, tick marks on the border at every grid interval with their coordinate written beside them, and a small cross at each grid intersection inside. What GridRef does This is what turns a site plan into a drawing someone can set out from. Without it … [Read more...] about GRIDREF LISP: Survey Coordinate Grid Over a Viewport

GRAPHGRID draws a ruled grid with both axes numbered — the background for a section through a road or drain, a settlement plot, a load curve, a pressure test, anything read off rather than dimensioned. What GraphGrid does Each axis takes a starting value, how much each square is worth, and how often to write a number. So a chainage axis can run 0, 25, 50 in … [Read more...] about GRAPHGRID LISP: Ruled and Numbered Graph Paper in AutoCAD

GANTTCHART draws a construction programme as a bar chart: a task name column down the left, twelve months across the top, and a coloured bar per task spanning from its start date to its finish. What GanttChart does It is drawn as ordinary AutoCAD geometry, so it plots as part of the drawing set and lives on the sheet with everything else — which is the whole … [Read more...] about GANTTCHART LISP: Draw a Programme Bar Chart in AutoCAD