diff --git a/packages/fragments/src/Importers/IfcImporter/src/types.ts b/packages/fragments/src/Importers/IfcImporter/src/types.ts
index a5762d4..a593ab9 100644
--- a/packages/fragments/src/Importers/IfcImporter/src/types.ts
+++ b/packages/fragments/src/Importers/IfcImporter/src/types.ts
@@ -1,3 +1,5 @@
+import type { ModelLoadCallback } from "web-ifc";
+
 export interface ProgressData {
   process: "geometries" | "attributes" | "relations" | "conversion";
   state: "start" | "inProgress" | "finish";
@@ -7,9 +9,31 @@ export interface ProgressData {
 
 export interface ProcessData {
   id?: string;
-  readFromCallback?: boolean;
   bytes?: Uint8Array;
-  readCallback?: any;
+  /**
+   * @see {@link readCallback}
+   * @default false
+   */
+  readFromCallback?: boolean;
+  /**
+   * Read ifc file incrementally, instead of passing {@link bytes}.
+   *
+   * @example node.js
+   * ```typescript
+   * import { open } from "node:fs/promises";
+   *
+   * const handle = await open(filePath, "r");
+   * const chunkSize = 64 * 1024; // 64KB
+   * const buffer = new Uint8Array(chunkSize);
+   * const readCallback: ((offset: number) => {
+   *   const bytesRead = readSync(handle.fd, buffer, 0, chunkSize, offset);
+   *   return buffer.slice(0, bytesRead);
+   * })
+   * const output = await importer.process({ readFromCallback: true, readCallback });
+   * await handle.close();
+   * ```
+   */
+  readCallback?: ModelLoadCallback;
   raw?: boolean;
   progressCallback?: (progress: number, data: ProgressData) => void;
 }