OpenSCAD (.scad)

@modelscript/scad (languages/scad) parses parametric OpenSCAD scripts and evaluates Constructive Solid Geometry (CSG) trees via @modelscript/cad into exact OpenCascade B-Rep solids, watertight triangle meshes, STEP AP214/AP242 exports, and Modelica MultiBody parameters.

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Supported Syntax & Fluent Method Chaining

In addition to standard OpenSCAD primitives (cube, sphere, cylinder, polyhedron, circle, square, polygon), boolean operations (union, difference, intersection, hull, minkowski), extrusions (linear_extrude, rotate_extrude), and control flow (module, function, for, if/else), @modelscript/scad supports fluent method chaining (ChainedSolid in languages/scad/src/evaluator.ts) and boundary port tagging:

wall_thickness = 4.0;
mount_radius = 12.0;

// Fluent method chaining with .fillet(), .chamfer(), .translate(), .rotate()
bracket = cube([60, 40, wall_thickness], center=true)
  .fillet(1.5)
  .translate([0, 0, wall_thickness / 2]);

// Explicit physical port tagging for SysML v2 / Modelica MultiBody & CFD/FEA binding
tag_port("base_mount", "frame", [0, 0, -1])
  difference() {
    bracket;
    cylinder(h=10, r=mount_radius, center=true).chamfer(0.5);
  }

Supported Chained Methods (ChainedSolid)

Method	Signature	Description
.translate(v)	translate([dx, dy, dz])	Translates the solid by vector [dx, dy, dz]
.rotate(a, v?)	rotate([rx, ry, rz]) or rotate(deg, axis)	Rotates the solid by Euler angles or axis-angle
.scale(v)	scale([sx, sy, sz])	Scales the solid non-uniformly or uniformly
.mirror(v)	mirror([nx, ny, nz])	Mirrors the solid across the plane with normal v
.color(c, alpha?)	color("steelblue", 0.9)	Assigns RGBA display metadata
.fillet(r)	fillet(radius)	Applies a 3D edge fillet of radius $r>0$
.chamfer(d)	chamfer(distance)	Applies a 3D edge chamfer of distance $d>0$

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Semantic Linter & Diagnostic Codes

lintScadCst(sourceText) (languages/scad/src/linter.ts) performs static scope resolution, constant folding, and geometric validity checking across 9 diagnostic rules:

8 rules7 error1 warning Run with msx lint

Code	Rule	Severity	Message
K1001	SCAD_UNDEFINED_VARIABLE	error	Undefined variable '<name>'.
K1002	SCAD_UNDEFINED_FUNCTION	error	Undefined function '<name>'.
K1003	SCAD_UNDEFINED_MODULE	error	Undefined module '<name>'.
K1004	SCAD_DIVISION_BY_ZERO	error	Division by zero in expression.
K1005	SCAD_INVALID_DIMENSION	error	Invalid non-positive dimension (<val>) in '<param>': dimensions must be > 0.
K1006	SCAD_ARGUMENT_COUNT	error	Too many arguments to '<name>': expected at most <expected>, got <actual>.
K1007	SCAD_UNKNOWN_PARAMETER	error	Unknown parameter '<param>' in call to '<callable>'.
K1008	SCAD_DUPLICATE_DECLARATION	warning	Variable '<name>' is assigned multiple times in the same scope.

Generated from languages/scad/src/errors.ts. All languages →

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3D Viewport Gizmo Writeback (ScadPatcher) & STEP Export

• Surgical AST Writeback (ScadPatcher in languages/scad/src/patcher.ts): When a user drags a 3D translation/rotation/scale gizmo in the CAD viewport, ScadPatcher (patchNode, patchVariable, patchTransformArgument, patchVectorComponent, wrapPrimitiveWithTransform, patchOrInsertTransform) updates the exact CST byte spans in the .scad source without reformatting surrounding code or comments.
• STEP AP214/AP242 Export (compileScadToStep): Evaluates the .scad CSG tree and serializes exact B-Rep analytical surfaces (PLANE, CYLINDRICAL_SURFACE, SPHERICAL_SURFACE, MANIFOLD_SOLID_BREP) to ISO 10303-21 .step.

# Project a parametric OpenSCAD file to an ISO 10303-21 STEP CAD file
npx msx polyglot project bracket.scad --target step --out bracket.step

# Or extract Embedded CSG from a Modelica model to OpenSCAD
npx msx csg SatelliteChassis satellite.mo > bracket.scad

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Polyglot TGG Rules

@modelscript/scad registers 13 bidirectional Triple Graph Grammar (TGG) rules in languages/scad/src/language.ts:

Rule Name	Source (scad)	Target Language	Target Construct
ScadModuleToSysmlPart	ModuleDeclaration	sysml2	PartDef
ScadProjectedAreaToModelicaParam	ScadScript (projectedArea, volume)	modelica	ComponentClause (parameter Real)
ScadProjectedAreaToSysmlAttribute	ScadScript (projectedArea, volume)	sysml2	AttributeUsage
ScadTagPortToSysmlPort	ModuleInstantiation (tag_port)	sysml2	PortUsage
ScadVariableToSysmlAttribute	VariableAssignment	sysml2	AttributeUsage
ScadSolidToStepProduct	ModuleInstantiation (cube)	step	DataEntity (PRODUCT)
ScadCylinderToStepProduct	ModuleInstantiation (cylinder)	step	DataEntity (CYLINDRICAL_SURFACE)
ScadSphereToStepProduct	ModuleInstantiation (sphere)	step	DataEntity (SPHERICAL_SURFACE)
ScadBooleanOpToStepComposite	ModuleInstantiation (union / difference / intersection)	step	DataEntity (BOOLEAN_RESULT)
ScadTagPortToModelicaFrame	ModuleInstantiation (tag_port)	modelica	ComponentClause (Modelica.Mechanics.MultiBody.Interfaces.Frame_a)
ScadCubeToMultiBodyShape	ModuleInstantiation (cube)	modelica	ComponentClause (Modelica.Mechanics.MultiBody.Visualizers.FixedShape "box")
ScadCylinderToMultiBodyShape	ModuleInstantiation (cylinder)	modelica	ComponentClause (Modelica.Mechanics.MultiBody.Visualizers.FixedShape "cylinder")
ScadSphereToMultiBodyShape	ModuleInstantiation (sphere)	modelica	ComponentClause (Modelica.Mechanics.MultiBody.Visualizers.FixedShape "sphere")