SCRIPT - Python Macro API

Write and run Python macros with the SCRIPT command through the mcad object for automation.

What it does

SCRIPT runs a Python (.py) file inside MCAD. It is comparable to AutoLISP/VBA. Use it to build repeated drawings, number items, or edit many drawings automatically. Every change a macro makes can be undone with Ctrl+Z.

Where to find it

Ribbon: type the command
Command line: SCRIPT (Alias SCR, MACRO)

Steps

Create a file grid_holes.py with Notepad:

# MCAD macro demo: a plate with a 4 x 3 hole grid
mcad.add_rect(0, 0, 200, 120, layer="OUTLINE")
for i in range(4):
    for j in range(3):
        mcad.add_circle(40 + i * 40, 30 + j * 30, 5, layer="HOLES")
mcad.add_text(0, -15, "GRID PLATE 4x3", height=6)
mcad.zoom_fit()
mcad.log(f"{mcad.entity_count} entities")

Type SCRIPT and press Enter, then choose the file (or SCRIPT C:\Macros\grid_holes.py).
The result appears in the drawing, and the Status bar shows SCRIPT done: grid_holes.py.

Macro result: a plate with a 4 x 3 hole grid

API reference

Document

Command	Meaning
`mcad.entity_count`	Number of objects
`mcad.entities()`	List of objects (dicts)
`mcad.entity(i)`	Object number i
`mcad.open(path)`	Open a DWG/DXF file
`mcad.save()`	Save the current drawing

Create objects (returns the index of the new object)

Command	Meaning
`mcad.add_line(x1, y1, x2, y2, **style)`	Line
`mcad.add_circle(cx, cy, r, **style)`	Circle
`mcad.add_arc(cx, cy, r, start_deg, end_deg, **style)`	Arc
`mcad.add_rect(x, y, w, h, **style)`	Rectangle
`mcad.add_polyline([(x, y), ...], closed=False, **style)`	Polyline
`mcad.add_text(x, y, "text", height=2.5, **style)`	Text
`mcad.add_entities([dict, ...])`	Add several objects in one Undo step (fast for many objects)

**style: layer="...", color="#RRGGBB" (or an ACI number), linetype="DASHED", lineweight=25 (= 0.25 mm)

Edit and other commands

Command	Meaning
`mcad.move(indices, dx, dy)`	Move
`mcad.erase(indices)`	Erase
`mcad.select(indices)` / `mcad.selection()` / `mcad.clear_selection()`	Manage the selection
`mcad.zoom_fit()` / `mcad.redraw()`	Zoom to fit / redraw
`mcad.command("ZOOM E")`	Run any Command line command
`mcad.log("msg")`	Show a message on the Status bar
`mcad.math`	Python's `math` module

Note: If a macro fails, a window shows the Traceback and the program does not close. Editing an object's dict directly bypasses the Undo system, so use the mcad commands instead.

Try it: Vent plate for an enclosure door

A 300 x 200 louvre plate for a hot control cabinet: 18 rounded slots in three columns plus four fixing holes. Drawing 72 lines and arcs by hand is no fun; a 20-line macro does it in a blink, and changing one number redraws the whole pattern.

Save this as vent_plate.py:

# MCAD macro: enclosure door vent plate with 3 x 6 louvre slots
W, H = 300, 200
mcad.add_rect(0, 0, W, H, layer="OUTLINE")
for (x, y) in ((10, 10), (W - 10, 10), (10, H - 10), (W - 10, H - 10)):
    mcad.add_circle(x, y, 3.5, layer="HOLES")
slot_w, slot_h, r = 70, 8, 4
for col in range(3):
    for row in range(6):
        x0 = 40 + col * 80
        y0 = 35 + row * 24
        mcad.add_line(x0 + r, y0, x0 + slot_w - r, y0, layer="SLOTS")
        mcad.add_line(x0 + r, y0 + slot_h, x0 + slot_w - r, y0 + slot_h, layer="SLOTS")
        mcad.add_arc(x0 + r, y0 + r, r, 90, 270, layer="SLOTS")
        mcad.add_arc(x0 + slot_w - r, y0 + r, r, -90, 90, layer="SLOTS")
mcad.add_text(0, -15, "VENT PLATE 300 x 200 - 18 SLOTS", height=7)
mcad.zoom_fit()
mcad.log(f"{mcad.entity_count} entities")

Type SCRIPT and choose vent_plate.py.
The plate appears and the Status bar reports the run. The drawing now holds 78 objects: the plate, 4 holes, 72 slot lines and arcs and the title.

Vent plate with 18 louvre slots generated by the macro

Challenge: Change range(6) to range(5) and slot_w to 90, erase the old plate and run the script again.