Execute many drawing ops in ONE call - ALWAYS prefer this over single tools for 3+ entities. Each op is {"type":...} + params (optional "layer"). Types: line(x1,y1,x2,y2) circle(cx,cy,radius) arc(cx,cy,radius,start_angle,end_angle) rectangle(x1,y1,x2,y2) polyline(points,closed) point(x,y) text(x,y,text,height,rotation) mtext(x,y,text,width,height) ellipse(cx,cy,major_dx,major_dy,ratio) layer(name,color: set current) center_mark(x,y,size) bolt_circle(cx,cy,pcd,hole_dia,count) hatch(points,pattern,scale,angle) dim_linear/dim_aligned(x1,y1,x2,y2,line_x,line_y) polygon(cx,cy,sides,radius) slot(x1,y1,x2,y2,width) rounded_rect(x1,y1,x2,y2,radius). Returns OK n= h=.

Line from (x1,y1) to (x2,y2).

Circle at (cx,cy) with radius.

Arc: center, radius, start/end angles in degrees (CCW).

Ellipse: center (cx,cy), major-axis endpoint (major_dx,major_dy) relative to center, ratio=minor/major.

Rectangle (closed polyline) between opposite corners.

Polyline through [[x,y],...]; closed=true to close it.

Point at (x,y).

Single-line text at (x,y); rotation in degrees.

Multiline text; (x,y)=top-left corner, width=wrap width.

N holes on a pitch-circle diameter (pcd), positions computed server-side; one call.

Center-mark cross at (x,y).

Fill a closed polygon with a real HATCH entity (pattern ANSI31, SOLID, ...).

Regular polygon: center, number of sides, circumscribed radius, rotation degrees.

Slot/obround (asola, oblong hole): rounded-end slot between the two arc centers, given width. Use this for slots - NOT a rectangle.

Rectangle with rounded corners (raccordato), single polyline.

Smooth spline through the given points [[x,y],...].

Infinite construction line through (x,y) at angle degrees.

Donut (filled ring; inner_dia=0 gives a filled dot).

Chamfer (bevel) ALL corners of a polyline with equal distances.

Hatch a circular area (creates the circle boundary + HATCH).

Offset a curve by distance toward the side of point (toward_x,toward_y). CAD does the math.

Fillet (round) ALL corners of a polyline with the given radius. CAD does the math.

Mirror entities across the axis (x1,y1)-(x2,y2). Draw half, mirror the rest. handles=['selection'] uses the GUI selection.

Rectangular array of entities: rows x cols with spacings. handles=['selection'] uses the GUI selection.

Polar array: copy entities count times around (cx,cy) over angle degrees. handles=['selection'] uses the GUI selection.

Bounding box of the whole drawing or of one layer: cheap spatial check, no screenshot.

Length (and area if closed) of a curve: line, arc, circle, polyline, spline.

Do two entities intersect/overlap? Returns intersection points. The anti-collision check.

Volume and centroid of a 3D solid.

Key points of an entity (ends/mid/center/radius/vertices): connect geometry without math.

Create a layer with ACI color (1=red 2=yellow 3=green 4=cyan 5=blue 6=magenta 7=white).

Set current layer (created with color if missing).

Set current entity color (ACI code; 256=ByLayer).

List layers with colors.

Insert a block (or .dwg file) at (x,y); rotation in degrees.

Define a reusable block from existing entities (they become the definition; re-place with insert_block).

Create/set a text style with a font (e.g. isocpeur.ttf for ISO drawings) and make it current.

List block definitions in the drawing.

Delete the last created entity.

Delete an entity by handle, or handle='selection' for the user's GUI selection.

Move ALL entities by (dx,dy).

Move entity by (dx,dy); handle='selection' moves the user's GUI selection.

Copy entity with offset (dx,dy); handle='selection' copies the user's GUI selection.

Rotate one entity (or 'selection') around a base point by angle degrees (CCW).

Scale one entity (or 'selection') from a base point by factor.

Change properties of an entity (or 'selection'): layer, color (ACI, 256=ByLayer), linetype.

Explode a block/polyline/dimension into its components.

Join touching lines/arcs/polylines into one polyline (first handle = source).

Break an entity between two points (opens a gap; same point twice = split only).

Rotate ALL entities around a base point by angle degrees (CCW).

Scale ALL entities from a base point by factor.

Linear (horiz/vert) dimension between two points; (line_x,line_y)=dimension line position.

Aligned (parallel) dimension between two points; (line_x,line_y)=dimension line position.

Radius dimension (R...) on a circle/arc by handle; angle=where it points (deg), offset=leader length factor.

Diameter dimension (D...) on a circle/arc by handle.

Angular dimension: vertex + a point on each side + dimension arc position.

Undo the last N operations (a whole draw_batch counts as ONE).

Redo the last undone operation.

What the user has currently selected in the GUI (count, handles, types, layers). Enables 'do X on what I selected'.

Select+highlight entities by type and/or layer (wildcards ok: layer='MUR*'). Returns handles; user SEES the selection.

Select+highlight by rectangular area: crossing=false only fully-inside, true also touching. Optional type/layer filter.

Total entity count (OK n=).

Instant census: entity count per type (cheap; call this FIRST to understand a drawing).

Per-layer report: object count, color, linetype, frozen/locked.

List entities (type, handle, layer), paginated; optional type/layer filter (wildcards ok). Use get_entity_counts first on big drawings.

Raw DXF data of an entity by handle.

Read a system variable (e.g. CLAYER, DIMSCALE).

Assign a linetype to a layer: CENTER (chain, for axes), HIDDEN, DASHED, PHANTOM, CONTINUOUS. Loads it if missing; ltscale>0 sets global linetype scale.

Appearance of NEW dimensions: text height, arrow size, decimal places, overall scale.

Leader arrow: points at (x,y) [the feature], text lands at (end_x,end_y). For callouts like '4x D10'.

HATCH the outer closed polygon SKIPPING the island polygons (hatch around holes). outer=[[x,y],...], islands=[[[x,y],...],...].

Trim: remove the portion of the entity at pick point, cut by the cutting entity.

Extend: lengthen the entity (picked near the end to extend) until the boundary entity.

Zoom to drawing extents.

Zoom to a rectangular window.

Regenerate the view.

Save the drawing as DWG (2018) to path.

Export the drawing to PDF at path (the final deliverable).

Render the drawing to a clean PNG (no UI chrome) for visual inspection. Pass a window (x1,y1,x2,y2) to frame a region; omit for current view.

Export the drawing as ASCII DXF to path.

3D solid box: base corner (x,y,z), sizes dx,dy,dz (dz along Z).

3D solid cylinder: base center (cx,cy,z), radius, height along Z.

3D solid sphere: center (cx,cy,z), radius.

3D solid cone: base center (cx,cy,z), base radius, height along Z.

3D solid wedge (ramp): base corner (x,y,z), sizes dx,dy,dz.

3D solid torus: center (cx,cy,z), ring radius, tube radius.

Sweep a closed 2D profile along a path curve -> 3D solid (pipes, rails, gaskets).

Slice a 3D solid with a vertical plane through 2 points; keep='both' or a point-side 'x,y'.

Extrude a CLOSED 2D profile (polyline/circle) into a 3D solid, height along Z. The 2D->3D bridge.

Revolve a CLOSED 2D profile around axis (x1,y1)-(x2,y2) by angle degrees (turned parts).

Union 3D solids into one.

Subtract solids from solids (holes, pockets). keep = the part, subtract = the tools.

Keep only the intersection of 3D solids.

3D view: direction iso/iso2/top/front/back/left/right; shade wireframe/hidden/flat/gouraud. Zooms extents.

Auto-generate a 2D drawing view (block) of ALL 3D solids, projected from direction (front/top/right/left/back/iso), lower-left corner placed at (x,y). Model in 3D, get the 2D view for free. Returns block handle+size.

Back to flat 2D view (top, wireframe, zoom extents). Use after 3D work.

Purge unused layers, blocks, linetypes, styles from the drawing.

Run any BricsCAD command; tokens list, "" = Enter. Prefer dedicated tools when they exist.

Eval AutoLISP code (multi-line and multiple expressions OK); set (setq MCPRES ...) to return data.