@@ -172,5 +172,21 @@ class Annotation
     String text;
   end Choice;
 
+  // CAD Integration
+
+  record CAD
+    String uri "URI to the STEP or GLTF file";
+    Real scale[3] = {1, 1, 1};
+    Real position[3] = {0, 0, 0};
+    Real rotation[4] = {0, 0, 0, 1} "Quaternion";
+  end CAD;
+
+  record CADPort
+    String feature "Name of the CAD feature (e.g., face, edge, vertex) to mate with";
+    Real offsetScale[3] = {1, 1, 1};
+    Real offsetPosition[3] = {0, 0, 0};
+    Real offsetRotation[4] = {0, 0, 0, 1};
+  end CADPort;
+
 end Annotation;
 `;
@@ -2094,6 +2094,8 @@ export abstract class ModelicaVariable extends ModelicaPrimaryExpression {
   arrayDimensions: number[] | null;
   /** Clock domain index (undefined = continuous time). */
   clockDomain?: number | undefined;
+  /** Extracted CAD / 3D annotations (as raw string or JSON), e.g. "CAD(uri=\"...\")" */
+  cadAnnotationString: string | null;
 
   constructor(
     name: string,
@@ -2121,6 +2123,7 @@ export abstract class ModelicaVariable extends ModelicaPrimaryExpression {
     this.arrayDimensions = null;
     /** Clock domain index (undefined = continuous time). */
     this.clockDomain = undefined;
+    this.cadAnnotationString = null;
   }
 
   override get hash(): string {
@@ -2158,7 +2161,8 @@ export class ModelicaBooleanVariable extends ModelicaVariable {
     return this.attributes.get("start") ?? null;
   }
 
-  override get toJSON(): string {
+  override get toJSON(): JSONValue {
+    if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };
     return this.name;
   }
 
@@ -2201,7 +2205,8 @@ export class ModelicaIntegerVariable extends ModelicaVariable {
     return this.attributes.get("start") ?? null;
   }
 
-  override get toJSON(): string {
+  override get toJSON(): JSONValue {
+    if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };
     return this.name;
   }
 
@@ -2256,7 +2261,8 @@ export class ModelicaRealVariable extends ModelicaVariable {
     return this.attributes.get("stateSelect") ?? null;
   }
 
-  override get toJSON(): string {
+  override get toJSON(): JSONValue {
+    if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };
     return this.name;
   }
 
@@ -2299,7 +2305,8 @@ export class ModelicaStringVariable extends ModelicaVariable {
     return this.attributes.get("start") ?? null;
   }
 
-  override get toJSON(): string {
+  override get toJSON(): JSONValue {
+    if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };
     return this.name;
   }
 
@@ -2322,7 +2329,8 @@ export class ModelicaExpressionVariable extends ModelicaVariable {
     return visitor.visitExpressionVariable(this, argument);
   }
 
-  override get toJSON(): string {
+  override get toJSON(): JSONValue {
+    if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };
     return this.name;
   }
 
@@ -2345,7 +2353,8 @@ export class ModelicaClockVariable extends ModelicaVariable {
     return visitor.visitClockVariable(this, argument);
   }
 
-  override get toJSON(): string {
+  override get toJSON(): JSONValue {
+    if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };
     return this.name;
   }
 
@@ -2414,7 +2423,8 @@ export class ModelicaEnumerationVariable extends ModelicaVariable {
     return this.attributes.get("start") ?? null;
   }
 
-  override get toJSON(): string {
+  override get toJSON(): JSONValue {
+    if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };
     return this.name;
   }
 
@@ -4270,6 +4280,7 @@ export class ModelicaDAEPrinter extends ModelicaDAEVisitor<never> {
       variable.expression.accept(this);
     }
     if (variable.description) this.out.write(' "' + variable.description + '"');
+    if (variable.cadAnnotationString) this.out.write(" annotation(" + variable.cadAnnotationString + ")");
     this.out.write(";\n");
   }
 
 
@@ -1440,6 +1440,39 @@ export class ModelicaFlattener extends ModelicaModelVisitor<[string, ModelicaDAE
     }
 
     if (variable) {
+      // Extract CAD and CADPort annotations
+      const formatCADAnnotation = (modName: string, modArg: { modificationArguments: unknown[] }): string => {
+        const parts: string[] = [];
+        for (const arg of modArg.modificationArguments) {
+          if (arg instanceof ModelicaElementModification && arg.name) {
+            const expr = arg.expression;
+            if (expr instanceof ModelicaStringLiteral) parts.push(`${arg.name}="${expr.value}"`);
+            else if (expr instanceof ModelicaRealLiteral || expr instanceof ModelicaIntegerLiteral)
+              parts.push(`${arg.name}=${expr.value}`);
+            else if (expr instanceof ModelicaBooleanLiteral) parts.push(`${arg.name}=${expr.value ? "true" : "false"}`);
+            else if (expr instanceof ModelicaArray) {
+              const vals = expr.elements
+                .map((e) => (e instanceof ModelicaRealLiteral || e instanceof ModelicaIntegerLiteral ? e.value : 0))
+                .join(", ");
+              parts.push(`${arg.name}={${vals}}`);
+            }
+          }
+        }
+        return `${modName}(${parts.join(", ")})`;
+      };
+
+      if (node.annotations && Array.isArray(node.annotations)) {
+        const cadAnnotation = node.annotations.find((a) => a.name === "CAD");
+        if (cadAnnotation instanceof ModelicaClassInstance && cadAnnotation.modification) {
+          variable.cadAnnotationString = formatCADAnnotation("CAD", cadAnnotation.modification);
+        } else {
+          const cadPortAnnotation = node.annotations.find((a) => a.name === "CADPort");
+          if (cadPortAnnotation instanceof ModelicaClassInstance && cadPortAnnotation.modification) {
+            variable.cadAnnotationString = formatCADAnnotation("CADPort", cadPortAnnotation.modification);
+          }
+        }
+      }
+
       // Set flow/stream prefix for connector variables
       if (node.flowPrefix === ModelicaFlow.FLOW) variable.flowPrefix = "flow";
       else if (node.flowPrefix === ModelicaFlow.STREAM) variable.flowPrefix = "stream";
Original file line number	Diff line number	Diff line change
`@@ -2094,6 +2094,8 @@ export abstract class ModelicaVariable extends ModelicaPrimaryExpression {`
`2094`	`2094`	`arrayDimensions: number[] \| null;`
`2095`	`2095`	`/** Clock domain index (undefined = continuous time). */`
`2096`	`2096`	`clockDomain?: number \| undefined;`
	`2097`	`+ /** Extracted CAD / 3D annotations (as raw string or JSON), e.g. "CAD(uri=\"...\")" */`
	`2098`	`+ cadAnnotationString: string \| null;`
`2097`	`2099`
`2098`	`2100`	`constructor(`
`2099`	`2101`	`name: string,`
`@@ -2121,6 +2123,7 @@ export abstract class ModelicaVariable extends ModelicaPrimaryExpression {`
`2121`	`2123`	`this.arrayDimensions = null;`
`2122`	`2124`	`/** Clock domain index (undefined = continuous time). */`
`2123`	`2125`	`this.clockDomain = undefined;`
	`2126`	`+ this.cadAnnotationString = null;`
`2124`	`2127`	`}`
`2125`	`2128`
`2126`	`2129`	`override get hash(): string {`
`@@ -2158,7 +2161,8 @@ export class ModelicaBooleanVariable extends ModelicaVariable {`
`2158`	`2161`	`return this.attributes.get("start") ?? null;`
`2159`	`2162`	`}`
`2160`	`2163`
`2161`		`- override get toJSON(): string {`
	`2164`	`+ override get toJSON(): JSONValue {`
	`2165`	`+ if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };`
`2162`	`2166`	`return this.name;`
`2163`	`2167`	`}`
`2164`	`2168`
`@@ -2201,7 +2205,8 @@ export class ModelicaIntegerVariable extends ModelicaVariable {`
`2201`	`2205`	`return this.attributes.get("start") ?? null;`
`2202`	`2206`	`}`
`2203`	`2207`
`2204`		`- override get toJSON(): string {`
	`2208`	`+ override get toJSON(): JSONValue {`
	`2209`	`+ if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };`
`2205`	`2210`	`return this.name;`
`2206`	`2211`	`}`
`2207`	`2212`
`@@ -2256,7 +2261,8 @@ export class ModelicaRealVariable extends ModelicaVariable {`
`2256`	`2261`	`return this.attributes.get("stateSelect") ?? null;`
`2257`	`2262`	`}`
`2258`	`2263`
`2259`		`- override get toJSON(): string {`
	`2264`	`+ override get toJSON(): JSONValue {`
	`2265`	`+ if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };`
`2260`	`2266`	`return this.name;`
`2261`	`2267`	`}`
`2262`	`2268`
`@@ -2299,7 +2305,8 @@ export class ModelicaStringVariable extends ModelicaVariable {`
`2299`	`2305`	`return this.attributes.get("start") ?? null;`
`2300`	`2306`	`}`
`2301`	`2307`
`2302`		`- override get toJSON(): string {`
	`2308`	`+ override get toJSON(): JSONValue {`
	`2309`	`+ if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };`
`2303`	`2310`	`return this.name;`
`2304`	`2311`	`}`
`2305`	`2312`
`@@ -2322,7 +2329,8 @@ export class ModelicaExpressionVariable extends ModelicaVariable {`
`2322`	`2329`	`return visitor.visitExpressionVariable(this, argument);`
`2323`	`2330`	`}`
`2324`	`2331`
`2325`		`- override get toJSON(): string {`
	`2332`	`+ override get toJSON(): JSONValue {`
	`2333`	`+ if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };`
`2326`	`2334`	`return this.name;`
`2327`	`2335`	`}`
`2328`	`2336`
`@@ -2345,7 +2353,8 @@ export class ModelicaClockVariable extends ModelicaVariable {`
`2345`	`2353`	`return visitor.visitClockVariable(this, argument);`
`2346`	`2354`	`}`
`2347`	`2355`
`2348`		`- override get toJSON(): string {`
	`2356`	`+ override get toJSON(): JSONValue {`
	`2357`	`+ if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };`
`2349`	`2358`	`return this.name;`
`2350`	`2359`	`}`
`2351`	`2360`
`@@ -2414,7 +2423,8 @@ export class ModelicaEnumerationVariable extends ModelicaVariable {`
`2414`	`2423`	`return this.attributes.get("start") ?? null;`
`2415`	`2424`	`}`
`2416`	`2425`
`2417`		`- override get toJSON(): string {`
	`2426`	`+ override get toJSON(): JSONValue {`
	`2427`	`+ if (this.cadAnnotationString) return { name: this.name, cad: this.cadAnnotationString };`
`2418`	`2428`	`return this.name;`
`2419`	`2429`	`}`
`2420`	`2430`
`@@ -4270,6 +4280,7 @@ export class ModelicaDAEPrinter extends ModelicaDAEVisitor<never> {`
`4270`	`4280`	`variable.expression.accept(this);`
`4271`	`4281`	`}`
`4272`	`4282`	`if (variable.description) this.out.write(' "' + variable.description + '"');`
	`4283`	`+ if (variable.cadAnnotationString) this.out.write(" annotation(" + variable.cadAnnotationString + ")");`
`4273`	`4284`	`this.out.write(";\n");`
`4274`	`4285`	`}`
`4275`	`4286`