feat: add crs support

Author: agviegas

.gitignore

@@ -135,4 +135,5 @@ resources/frags/test
 resources/asdf2.frag
 resources/asdf2.json
 
-.DS_Store
+.DS_Store
+.claude/

packages/fragments/src/FragmentsModels/src/model/data-manager.ts

@@ -1,4 +1,5 @@
 import {
+  CRSData,
   MultiThreadingRequestClass,
   ItemsQueryParams,
   SpatialTreeItem,
@@ -114,6 +115,14 @@ export class DataManager {
     return model.threads.invoke(model.modelId, "getMetadata", []) as Promise<T>;
   }
 
+  async getCRS(model: FragmentsModel) {
+    return model.threads.invoke(
+      model.modelId,
+      "getCRS",
+      [],
+    ) as Promise<CRSData | null>;
+  }
+
   async getGuidsByLocalIds(model: FragmentsModel, localIds: number[]) {
     return model.threads.invoke(model.modelId, "getGuidsByLocalIds", [
       localIds,

packages/fragments/src/FragmentsModels/src/model/fragments-model.ts

@@ -259,6 +259,15 @@ export class FragmentsModel {
     return this._dataManager.getMetadata<T>(this);
   }
 
+  /**
+   * Get the Coordinate Reference System (CRS) data of the model, if available.
+   * Returns null if the source IFC file did not contain IFCPROJECTEDCRS
+   * or IFCCOORDINATEREFERENCESYSTEM entities.
+   */
+  async getCRS() {
+    return this._dataManager.getCRS(this);
+  }
+
   /**
    * Get the GUIDs corresponding to the specified local IDs.
    * @param localIds - Array of local IDs to look up.

packages/fragments/src/FragmentsModels/src/model/model-types.ts

@@ -420,6 +420,42 @@ export type GridData = {
   wAxes: GridAxisData[];
 };
 
+/**
+ * Interface representing the Coordinate Reference System (CRS) data
+ * extracted from an IFC model's IFCPROJECTEDCRS and IFCMAPCONVERSION entities.
+ */
+export interface CRSData {
+  /** The CRS name/identifier, e.g. "EPSG:3947" */
+  name: string | null;
+  /** Description of the CRS, e.g. "RGF93_CC47" */
+  description: string | null;
+  /** The geodetic datum name, e.g. "RGF93" */
+  geodeticDatum: string | null;
+  /** The vertical datum name */
+  verticalDatum: string | null;
+  /** The map projection name */
+  mapProjection: string | null;
+  /** The map zone identifier */
+  mapZone: string | null;
+  /** The map unit name, e.g. "METRE" */
+  mapUnit: string | null;
+  /** Map conversion parameters from IFCMAPCONVERSION (null if not present) */
+  mapConversion: {
+    /** Easting coordinate of the map origin */
+    eastings: number;
+    /** Northing coordinate of the map origin */
+    northings: number;
+    /** Orthogonal height of the map origin */
+    orthogonalHeight: number;
+    /** X component of the abscissa of the X axis */
+    xAxisAbscissa: number;
+    /** Y component of the ordinate of the X axis */
+    xAxisOrdinate: number;
+    /** Scale factor applied to the map */
+    scale: number;
+  } | null;
+}
+
 export type CustomDataItem = {
   data: {
     value: string;

packages/fragments/src/FragmentsModels/src/single-threading/index.ts

@@ -88,6 +88,13 @@ export class SingleThreadedFragmentsModel {
     return this._virtualModel.getMetadata() as T;
   }
 
+  /**
+   * Get the Coordinate Reference System (CRS) data of the model, if available.
+   */
+  getCRS() {
+    return this._virtualModel.getCRS();
+  }
+
   /**
    * Get the GUIDs corresponding to the specified local IDs.
    * @param localIds - Array of local IDs to look up.

packages/fragments/src/FragmentsModels/src/virtual-model/virtual-controllers/virtual-properties-controller.ts

@@ -5,6 +5,7 @@ import { Meshes, Model, SpatialStructure } from "../../../../Schema";
 import { Identifier } from "../../model";
 import {
   AttributesUniqueValuesParams,
+  CRSData,
   GetItemsByAttributeParams,
   GetItemsByRelationParams,
   ItemData,
@@ -154,6 +155,14 @@ export class VirtualPropertiesController {
     return JSON.parse(metadata);
   }
 
+  getCRS(): CRSData | null {
+    const metadata = this.getMetadata();
+    if (!metadata || !metadata.crs) {
+      return null;
+    }
+    return metadata.crs as CRSData;
+  }
+
   getItemIdsFromLocalIds(localIds?: Iterable<number>): number[] {
     if (!localIds) {
       return Array.from(this._model.meshes()!.meshesItemsArray()!);

packages/fragments/src/FragmentsModels/src/virtual-model/virtual-fragments-model.ts

@@ -189,6 +189,19 @@ export class VirtualFragmentsModel {
     return this.properties.getMetadata();
   }
 
+  getCRS() {
+    // If there are any changes to the metadata, check there too
+    const found = EditUtils.applyChangesToSpecialData(
+      this.requests,
+      "METADATA",
+    );
+    if (found && found.crs) {
+      return found.crs;
+    }
+
+    return this.properties.getCRS();
+  }
+
   getLocalIdsByGuids(guids: string[]) {
     return this.properties.getLocalIdsByGuids(guids);
   }

packages/fragments/src/Importers/IfcImporter/src/properties/property-processor.ts

@@ -673,12 +673,99 @@ export class IfcPropertyProcessor {
     const descriptions: string[] = [];
     this.getMetadataRecursively(rawDescription.arguments, descriptions);
 
-    const metadata = { schema, names, descriptions } as any;
+    const crs = this.extractCRS(ifcApi);
+
+    const metadata = { schema, names, descriptions, crs } as any;
 
     const metadataOffset = this._builder.createString(JSON.stringify(metadata));
     return metadataOffset;
   }
 
+  private extractCRS(ifcApi: WEBIFC.IfcAPI) {
+    // Try IFCPROJECTEDCRS first, then fall back to IFCCOORDINATEREFERENCESYSTEM
+    let crsEntity: any = null;
+    try {
+      const ids = ifcApi.GetLineIDsWithType(0, WEBIFC.IFCPROJECTEDCRS);
+      if (ids.size() > 0) {
+        crsEntity = ifcApi.GetLine(0, ids.get(0));
+      }
+    } catch {
+      // IFCPROJECTEDCRS may not exist in older IFC schemas
+    }
+
+    if (!crsEntity) {
+      try {
+        const ids = ifcApi.GetLineIDsWithType(
+          0,
+          WEBIFC.IFCCOORDINATEREFERENCESYSTEM,
+        );
+        if (ids.size() > 0) {
+          crsEntity = ifcApi.GetLine(0, ids.get(0));
+        }
+      } catch {
+        // Not available
+      }
+    }
+
+    if (!crsEntity) {
+      return null;
+    }
+
+    const name = this.unwrapValue(crsEntity.Name) ?? null;
+    const description = this.unwrapValue(crsEntity.Description) ?? null;
+    const geodeticDatum = this.unwrapValue(crsEntity.GeodeticDatum) ?? null;
+    const verticalDatum = this.unwrapValue(crsEntity.VerticalDatum) ?? null;
+    const mapProjection = this.unwrapValue(crsEntity.MapProjection) ?? null;
+    const mapZone = this.unwrapValue(crsEntity.MapZone) ?? null;
+
+    // Resolve MapUnit reference to get the unit name
+    let mapUnit: string | null = null;
+    try {
+      const unitRef = crsEntity.MapUnit;
+      if (unitRef && typeof unitRef === "object" && unitRef.type === 5) {
+        const unitEntity = ifcApi.GetLine(0, unitRef.value);
+        if (unitEntity) {
+          const unitName = this.unwrapValue(unitEntity.Name);
+          if (unitName) {
+            mapUnit = String(unitName);
+          }
+        }
+      }
+    } catch {
+      // Unit resolution failed
+    }
+
+    // Extract IFCMAPCONVERSION if present
+    let mapConversion = null;
+    try {
+      const convIds = ifcApi.GetLineIDsWithType(0, WEBIFC.IFCMAPCONVERSION);
+      if (convIds.size() > 0) {
+        const conv = ifcApi.GetLine(0, convIds.get(0));
+        mapConversion = {
+          eastings: this.unwrapValue(conv.Eastings) ?? 0,
+          northings: this.unwrapValue(conv.Northings) ?? 0,
+          orthogonalHeight: this.unwrapValue(conv.OrthogonalHeight) ?? 0,
+          xAxisAbscissa: this.unwrapValue(conv.XAxisAbscissa) ?? 1,
+          xAxisOrdinate: this.unwrapValue(conv.XAxisOrdinate) ?? 0,
+          scale: this.unwrapValue(conv.Scale) ?? 1,
+        };
+      }
+    } catch {
+      // IFCMAPCONVERSION may not exist
+    }
+
+    return {
+      name,
+      description,
+      geodeticDatum,
+      verticalDatum,
+      mapProjection,
+      mapZone,
+      mapUnit,
+      mapConversion,
+    };
+  }
+
   private getMetadataRecursively(source: any[], target: string[]) {
     for (const item of source) {
       if (item === null || item === undefined) continue;

packages/fragments/src/Importers/IfcImporter/test.ts

@@ -33,7 +33,7 @@ const run = async (serialize: boolean) => {
 
     // Read the file
     // const ifcFile = fs.readFileSync(`${name}${extension}`)
-    const url = "/resources/ifc/test/small_test.ifc";
+    const url = "/resources/ifc/test/crs.ifc";
     const ifcFile = await fetch(url);
     const ifcBuffer = await ifcFile.arrayBuffer();
     const typedArray = new Uint8Array(ifcBuffer);
@@ -145,6 +145,9 @@ const run = async (serialize: boolean) => {
       raw,
     });
 
+    const crs = await model.getCRS();
+    console.log(crs);
+
     world.scene.three.add(model.object);
 
     const absoluteAlignments = await model.getAlignments();