feat(canvas): import DWG/DXF CAD drawings as canvas assets

Accept DWG and DXF files (up to 24 MB) through the canvas asset picker and
drag-and-drop. Conversion runs locally in a browser worker via acad-ts,
uploads a sanitized derived SVG, and leaves the source file untouched. DXF
covers ASCII and binary drawings; DWG covers AutoCAD R14 through 2018.

Rename the image-only upload input/handler to a generic canvas asset flow,
add vector-image node detection, tag imported SVGs as vector-image nodes,
localize CAD import status/error messages, and switch the Next build to the
webpack compiler so the worker bundles correctly. Add a node --test suite
covering CAD conversion and vector image helpers.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

README.md

@@ -1,6 +1,6 @@
 # img-infinite-canvas
 
-Moteva 风格的 AI 设计工作台复刻 MVP：主页 Prompt 创建项目，项目页提供无限画布、节点拖拽、缩放平移、右侧设计对话、历史回放、图片资产上传、项目保存与再生成。
+Moteva 风格的 AI 设计工作台复刻 MVP：主页 Prompt 创建项目，项目页提供无限画布、节点拖拽、缩放平移、右侧设计对话、历史回放、图片与 DWG/DXF 图纸导入、项目保存与再生成。
 
 ## Stack
 
@@ -31,6 +31,10 @@ pnpm dev
 
 Open `http://localhost:5173`. Next.js rewrites `/api` to `http://localhost:8888` in development. `pnpm build` runs `next build` and `vite build`, producing gzip assets in `frontend/dist`.
 
+## CAD Import
+
+The canvas asset picker and drag-and-drop surface accept DWG and DXF files up to 24 MB. Conversion runs locally in a browser worker, uploads a sanitized derived SVG, and leaves the source file unchanged. DXF supports ASCII and binary drawings; DWG supports AutoCAD R14 through AutoCAD 2018 format families.
+
 ## Cache Config
 
 Default in-memory cache:

frontend/next-env.d.ts

@@ -1,6 +1,6 @@
 /// <reference types="next" />
 /// <reference types="next/image-types/global" />
-import "./.next/types/routes.d.ts";
+import "./.next/dev/types/routes.d.ts";
 
 // NOTE: This file should not be edited
 // see https://nextjs.org/docs/app/api-reference/config/typescript for more information.

frontend/package.json

@@ -4,13 +4,15 @@
   "private": true,
   "type": "module",
   "scripts": {
-    "dev": "next dev -H 0.0.0.0 -p 5173",
+    "dev": "next dev --webpack -H 0.0.0.0 -p 5173",
     "dev:vite": "vite --host 0.0.0.0",
-    "build": "tsc -b && next build && vite build",
+    "build": "tsc -b && next build --webpack && vite build",
+    "test": "node --experimental-strip-types --test tests/*.test.mjs",
     "start": "next start -H 0.0.0.0 -p 3000",
     "preview": "vite preview --host 0.0.0.0"
   },
   "dependencies": {
+    "@node-projects/acad-ts": "2.3.0",
     "@radix-ui/react-context-menu": "^2.3.2",
     "@radix-ui/react-dropdown-menu": "^2.1.19",
     "@radix-ui/react-popover": "^1.1.18",

frontend/pnpm-lock.yaml

@@ -5,6 +5,9 @@ settings:
   excludeLinksFromLockfile: false
 
 dependencies:
+  '@node-projects/acad-ts':
+    specifier: 2.3.0
+    version: 2.3.0
   '@radix-ui/react-context-menu':
     specifier: ^2.3.2
     version: 2.3.2(@types/react-dom@19.2.3)(@types/react@19.2.17)(react-dom@19.2.7)(react@19.2.7)
@@ -439,6 +442,10 @@ packages:
     dev: false
     optional: true
 
+  /@node-projects/acad-ts@2.3.0:
+    resolution: {integrity: sha512-qeEHH6apsBZPWVXx489ju0Qln/YyhIffREic+alksgj5F4KsaD+GAE96si1P8RNFbJbZQOSG85bo0749MpzCDA==}
+    dev: false
+
   /@oxc-project/types@0.138.0:
     resolution: {integrity: sha512-1a7ZKmrRTCoN1XMZ4L0PyyqrMnrNlLyPuOkdSX2MZg7IiIGRUyurNhAm73ptDOraoBcIordsIGKNPKUzy3ZmfA==}
     dev: true

frontend/src/i18n/locales/en-US.json

@@ -432,7 +432,15 @@
   "canvasCursor": "Canvas status",
   "imageNode": "Image node",
   "uploadImageNode": "Upload image node",
+  "uploadCanvasAsset": "Upload image or CAD file",
   "imageUploadSuccess": "Image uploaded",
+  "cadImportConverting": "Converting CAD drawing",
+  "cadImportSuccess": "Imported {count} CAD drawing(s)",
+  "cadImportTooLarge": "CAD files must be 24 MB or smaller.",
+  "cadImportTimeout": "CAD conversion timed out. Simplify the drawing and try again.",
+  "cadImportEmpty": "The CAD drawing has no visible model-space content.",
+  "cadImportUnsupported": "This browser cannot convert the selected CAD file.",
+  "cadImportFailed": "CAD conversion failed. Check that the file is complete and uses a supported version.",
   "uploadingImage": "Uploading",
   "extractingText": "Extract text",
   "textNode": "Text node",

frontend/src/i18n/locales/zh-CN.json

@@ -432,7 +432,15 @@
   "canvasCursor": "画布状态",
   "imageNode": "图片节点",
   "uploadImageNode": "上传图片节点",
+  "uploadCanvasAsset": "上传图片或 CAD 文件",
   "imageUploadSuccess": "图片上传成功",
+  "cadImportConverting": "正在转换 CAD 图纸",
+  "cadImportSuccess": "已导入 {count} 个 CAD 图纸",
+  "cadImportTooLarge": "CAD 文件不能超过 24 MB。",
+  "cadImportTimeout": "CAD 图纸转换超时，请尝试精简图纸后重试。",
+  "cadImportEmpty": "CAD 图纸中没有可显示的模型空间内容。",
+  "cadImportUnsupported": "当前浏览器无法转换此 CAD 文件。",
+  "cadImportFailed": "CAD 图纸转换失败，请确认文件完整且版本受支持。",
   "uploadingImage": "上传中",
   "extractingText": "提取文字",
   "textNode": "文本节点",

frontend/src/ui/lib/cadConversion.ts

@@ -0,0 +1,380 @@
+import * as Acad from "@node-projects/acad-ts";
+import type {
+  BlockRecord as CadBlockRecord,
+  CadDocument,
+  Color as CadColor,
+  Entity,
+  Insert as CadInsert,
+  UnitsType as CadUnitsType
+} from "@node-projects/acad-ts";
+
+const { Color, Dimension, DwgReader, DxfReader, Insert, LayerFlags, SvgConfiguration, SvgConverter, SvgXmlWriter, UnitsType } = Acad;
+
+export type CadFormat = "dwg" | "dxf";
+
+type AffineMatrix = {
+  a: number;
+  b: number;
+  c: number;
+  d: number;
+  e: number;
+  f: number;
+};
+
+type CadBounds = {
+  minX: number;
+  minY: number;
+  maxX: number;
+  maxY: number;
+};
+
+class EntityFragmentWriter extends SvgXmlWriter {
+  writeFragment(entity: Entity) {
+    this.writeEntity(entity);
+    return this.getOutput();
+  }
+}
+
+class CadEntitySvgWriter {
+  private fragmentIndex = 0;
+  private readonly configuration: InstanceType<typeof SvgConfiguration>;
+  private readonly units: CadUnitsType;
+
+  constructor(configuration: InstanceType<typeof SvgConfiguration>, units: CadUnitsType) {
+    this.configuration = configuration;
+    this.units = units;
+  }
+
+  writeFragment(entity: Entity) {
+    const writer = new EntityFragmentWriter(new ArrayBuffer(0), this.configuration);
+    writer.units = this.units;
+    return scopeFragmentIds(writer.writeFragment(entity), `cad-entity-${this.fragmentIndex++}`);
+  }
+}
+
+export function convertCadBufferToSvg(buffer: ArrayBuffer, format: CadFormat) {
+  restoreAcadClassNames();
+  const document = format === "dwg" ? DwgReader.readFromStream(buffer) : DxfReader.readFromStream(new Uint8Array(buffer));
+  return convertCadDocumentToSvg(document);
+}
+
+export function convertCadDocumentToSvg(document: CadDocument) {
+  const modelSpace = document.modelSpace;
+  if (!modelSpace || modelSpace.entities.count === 0) {
+    throw new Error("CAD drawing has no model-space entities");
+  }
+
+  resolveInheritedEntityColors(document);
+  const configuration = new SvgConfiguration();
+  configuration.arcPoints = 192;
+  const units = supportedSvgUnits(modelSpace.units);
+  const unitScale = SvgConverter.toPixelSize(1, units);
+  const writer = new CadEntitySvgWriter(configuration, units);
+
+  const { blockIds, cyclicReferences } = collectReferencedBlocks(modelSpace);
+  const blockBounds = createBlockBoundsResolver(cyclicReferences);
+  const bounds = normalizedBounds(boundsForEntities(modelSpace.entities, blockBounds, cyclicReferences));
+  const definitions = Array.from(blockIds, ([block, id]) => {
+    const content = renderEntities(block.entities, writer, blockIds, cyclicReferences, unitScale);
+    return `<g id="${id}">${content}</g>`;
+  }).join("");
+  const drawing = renderEntities(modelSpace.entities, writer, blockIds, cyclicReferences, unitScale);
+  if (!drawing.trim()) {
+    throw new Error("CAD drawing did not produce SVG output");
+  }
+
+  const minX = bounds.minX * unitScale;
+  const minY = bounds.minY * unitScale;
+  const width = (bounds.maxX - bounds.minX) * unitScale;
+  const height = (bounds.maxY - bounds.minY) * unitScale;
+  return `<?xml version="1.0" encoding="utf-8"?>\n<svg xmlns="http://www.w3.org/2000/svg" width="${svgNumber(width)}" height="${svgNumber(height)}" viewBox="${svgNumber(minX)} ${svgNumber(minY)} ${svgNumber(width)} ${svgNumber(height)}"><defs>${definitions}</defs><g>${drawing}</g></svg>`;
+}
+
+function renderEntities(
+  entities: Iterable<Entity>,
+  writer: CadEntitySvgWriter,
+  blockIds: ReadonlyMap<CadBlockRecord, string>,
+  cyclicReferences: ReadonlySet<Entity>,
+  unitScale: number
+) {
+  const output: string[] = [];
+  for (const entity of entities) {
+    if (!isVisibleEntity(entity)) continue;
+    if (entity instanceof Insert) {
+      const id = entity.block ? blockIds.get(entity.block) : undefined;
+      if (id && !cyclicReferences.has(entity)) {
+        for (const matrix of insertMatrices(entity)) {
+          output.push(`<use href="#${id}" transform="${svgMatrix(matrix, unitScale)}" />`);
+        }
+      }
+      for (const attribute of entity.attributes) {
+        if (isVisibleEntity(attribute)) output.push(writer.writeFragment(attribute));
+      }
+      continue;
+    }
+
+    if (entity instanceof Dimension) {
+      const id = entity.block ? blockIds.get(entity.block) : undefined;
+      if (id && !cyclicReferences.has(entity)) output.push(`<use href="#${id}" />`);
+      continue;
+    }
+
+    output.push(writer.writeFragment(entity));
+  }
+  return output.join("");
+}
+
+function collectReferencedBlocks(modelSpace: CadBlockRecord) {
+  const blockIds = new Map<CadBlockRecord, string>();
+  const cyclicReferences = new Set<Entity>();
+  const visiting = new Set<CadBlockRecord>();
+  const visited = new Set<CadBlockRecord>();
+
+  const visit = (block: CadBlockRecord) => {
+    if (visited.has(block)) return;
+    visiting.add(block);
+    for (const entity of block.entities) {
+      if (!isVisibleEntity(entity)) continue;
+      const referenced = referencedBlock(entity);
+      if (!referenced) continue;
+      if (visiting.has(referenced)) {
+        cyclicReferences.add(entity);
+        continue;
+      }
+      if (!blockIds.has(referenced)) blockIds.set(referenced, `cad-block-${blockIds.size}`);
+      visit(referenced);
+    }
+    visiting.delete(block);
+    visited.add(block);
+  };
+
+  visit(modelSpace);
+  return { blockIds, cyclicReferences };
+}
+
+function referencedBlock(entity: Entity) {
+  if (entity instanceof Insert || entity instanceof Dimension) return entity.block;
+  return null;
+}
+
+function insertMatrices(insert: CadInsert) {
+  const rowCount = positiveInteger(insert.rowCount);
+  const columnCount = positiveInteger(insert.columnCount);
+  const rotation = Number.isFinite(insert.rotation) ? insert.rotation : 0;
+  const cosine = Math.cos(rotation);
+  const sine = Math.sin(rotation);
+  const scaleX = finiteOr(insert.xScale, 1);
+  const scaleY = finiteOr(insert.yScale, 1);
+  const basePoint = insert.block?.blockEntity.basePoint;
+  const baseX = finiteOr(basePoint?.x, 0);
+  const baseY = finiteOr(basePoint?.y, 0);
+  const a = cosine * scaleX;
+  const b = sine * scaleX;
+  const c = -sine * scaleY;
+  const d = cosine * scaleY;
+  const matrices: AffineMatrix[] = [];
+
+  for (let row = 0; row < rowCount; row += 1) {
+    for (let column = 0; column < columnCount; column += 1) {
+      const offsetX = column * finiteOr(insert.columnSpacing, 0);
+      const offsetY = row * finiteOr(insert.rowSpacing, 0);
+      matrices.push({
+        a,
+        b,
+        c,
+        d,
+        e: finiteOr(insert.insertPoint.x, 0) + cosine * offsetX - sine * offsetY - a * baseX - c * baseY,
+        f: finiteOr(insert.insertPoint.y, 0) + sine * offsetX + cosine * offsetY - b * baseX - d * baseY
+      });
+    }
+  }
+  return matrices;
+}
+
+function createBlockBoundsResolver(cyclicReferences: ReadonlySet<Entity>) {
+  const cache = new Map<CadBlockRecord, CadBounds | null>();
+  const resolving = new Set<CadBlockRecord>();
+
+  const resolve = (block: CadBlockRecord): CadBounds | null => {
+    if (cache.has(block)) return cache.get(block) ?? null;
+    if (resolving.has(block)) return null;
+    resolving.add(block);
+    const bounds = boundsForEntities(block.entities, resolve, cyclicReferences);
+    resolving.delete(block);
+    cache.set(block, bounds);
+    return bounds;
+  };
+  return resolve;
+}
+
+function boundsForEntities(
+  entities: Iterable<Entity>,
+  blockBounds: (block: CadBlockRecord) => CadBounds | null,
+  cyclicReferences: ReadonlySet<Entity>
+) {
+  let bounds: CadBounds | null = null;
+  for (const entity of entities) {
+    if (!isVisibleEntity(entity)) continue;
+    if (entity instanceof Insert) {
+      const referencedBounds = entity.block && !cyclicReferences.has(entity) ? blockBounds(entity.block) : null;
+      if (referencedBounds) {
+        for (const matrix of insertMatrices(entity)) bounds = unionBounds(bounds, transformBounds(referencedBounds, matrix));
+      }
+      for (const attribute of entity.attributes) {
+        if (isVisibleEntity(attribute)) bounds = unionBounds(bounds, entityBounds(attribute));
+      }
+      continue;
+    }
+
+    if (entity instanceof Dimension) {
+      const referencedBounds = entity.block && !cyclicReferences.has(entity) ? blockBounds(entity.block) : null;
+      bounds = unionBounds(bounds, referencedBounds);
+      bounds = unionBounds(bounds, entityBounds(entity));
+      continue;
+    }
+
+    bounds = unionBounds(bounds, entityBounds(entity));
+  }
+  return bounds;
+}
+
+function entityBounds(entity: Entity) {
+  try {
+    const bounds = entity.getBoundingBox();
+    if (!bounds || !isFinitePoint(bounds.min) || !isFinitePoint(bounds.max)) return null;
+    return { minX: bounds.min.x, minY: bounds.min.y, maxX: bounds.max.x, maxY: bounds.max.y };
+  } catch {
+    return null;
+  }
+}
+
+function transformBounds(bounds: CadBounds, matrix: AffineMatrix) {
+  const points = [
+    transformPoint(bounds.minX, bounds.minY, matrix),
+    transformPoint(bounds.minX, bounds.maxY, matrix),
+    transformPoint(bounds.maxX, bounds.minY, matrix),
+    transformPoint(bounds.maxX, bounds.maxY, matrix)
+  ];
+  return {
+    minX: Math.min(...points.map((point) => point.x)),
+    minY: Math.min(...points.map((point) => point.y)),
+    maxX: Math.max(...points.map((point) => point.x)),
+    maxY: Math.max(...points.map((point) => point.y))
+  };
+}
+
+function transformPoint(x: number, y: number, matrix: AffineMatrix) {
+  return {
+    x: matrix.a * x + matrix.c * y + matrix.e,
+    y: matrix.b * x + matrix.d * y + matrix.f
+  };
+}
+
+function unionBounds(first: CadBounds | null, second: CadBounds | null) {
+  if (!first) return second;
+  if (!second) return first;
+  return {
+    minX: Math.min(first.minX, second.minX),
+    minY: Math.min(first.minY, second.minY),
+    maxX: Math.max(first.maxX, second.maxX),
+    maxY: Math.max(first.maxY, second.maxY)
+  };
+}
+
+function normalizedBounds(bounds: CadBounds | null) {
+  if (!bounds) throw new Error("CAD drawing has no visible bounds");
+  const normalized = { ...bounds };
+  if (normalized.maxX === normalized.minX) {
+    normalized.minX -= 0.5;
+    normalized.maxX += 0.5;
+  }
+  if (normalized.maxY === normalized.minY) {
+    normalized.minY -= 0.5;
+    normalized.maxY += 0.5;
+  }
+  return normalized;
+}
+
+function svgMatrix(matrix: AffineMatrix, unitScale: number) {
+  return `matrix(${svgNumber(matrix.a)} ${svgNumber(matrix.b)} ${svgNumber(matrix.c)} ${svgNumber(matrix.d)} ${svgNumber(matrix.e * unitScale)} ${svgNumber(matrix.f * unitScale)})`;
+}
+
+function scopeFragmentIds(fragment: string, prefix: string) {
+  const ids = new Map<string, string>();
+  const scoped = fragment.replace(/\bid="([^"]+)"/g, (_, id: string) => {
+    const nextId = `${prefix}-${ids.size}`;
+    ids.set(id, nextId);
+    return `id="${nextId}"`;
+  });
+  return scoped.replace(/url\(#([^)]+)\)/g, (match, id: string) => {
+    const nextId = ids.get(id);
+    return nextId ? `url(#${nextId})` : match;
+  });
+}
+
+function supportedSvgUnits(units: CadUnitsType) {
+  return units === UnitsType.Inches || units === UnitsType.Millimeters ? units : UnitsType.Unitless;
+}
+
+function positiveInteger(value: number) {
+  return Number.isFinite(value) && value > 0 ? Math.max(1, Math.floor(value)) : 1;
+}
+
+function finiteOr(value: number | null | undefined, fallback: number) {
+  return typeof value === "number" && Number.isFinite(value) ? value : fallback;
+}
+
+function isFinitePoint(point: { x: number; y: number }) {
+  return Number.isFinite(point.x) && Number.isFinite(point.y);
+}
+
+function isVisibleEntity(entity: Entity) {
+  if (entity.isInvisible || !entity.layer.isOn) return false;
+  return (entity.layer.layerFlags & LayerFlags.Frozen) === 0;
+}
+
+function svgNumber(value: number) {
+  if (!Number.isFinite(value)) return "0";
+  if (Math.abs(value) < 1e-12) return "0";
+  return String(Number(value.toPrecision(12)));
+}
+
+function resolveInheritedEntityColors(document: CadDocument) {
+  const visited = new Set<CadBlockRecord>();
+  const visit = (block: CadBlockRecord) => {
+    if (visited.has(block)) return;
+    visited.add(block);
+    for (const entity of block.entities) {
+      if (!isRenderableColor(entity.color)) entity.color = resolveEntityColor(entity);
+      if (entity instanceof Insert) {
+        for (const attribute of entity.attributes) {
+          if (!isRenderableColor(attribute.color)) attribute.color = resolveEntityColor(attribute);
+        }
+      }
+      const referenced = referencedBlock(entity);
+      if (referenced) visit(referenced);
+    }
+  };
+  for (const block of document.blockRecords ?? []) visit(block);
+  if (document.modelSpace) visit(document.modelSpace);
+}
+
+function resolveEntityColor(entity: Entity) {
+  const candidates = [entity.getActiveColor(), entity.layer.color, Color.default];
+  return candidates.find(isRenderableColor) ?? Color.default;
+}
+
+function isRenderableColor(color: CadColor | null | undefined) {
+  if (!color || color.isByBlock || color.isByLayer) return false;
+  const rgb = color.getRgb();
+  return Array.isArray(rgb) && rgb.length === 3 && rgb.every(Number.isFinite);
+}
+
+function restoreAcadClassNames() {
+  // acad-ts resolves DXF metadata by constructor.name, which production minifiers rename.
+  for (const [exportName, value] of Object.entries(Acad)) {
+    if (typeof value !== "function" || value.name === exportName) continue;
+    const descriptor = Object.getOwnPropertyDescriptor(value, "name");
+    if (descriptor?.configurable) Object.defineProperty(value, "name", { ...descriptor, value: exportName });
+  }
+}

frontend/src/ui/lib/cadImport.ts

@@ -0,0 +1,266 @@
+export type CadImportErrorCode = "conversion" | "empty" | "timeout" | "too-large" | "unsupported";
+
+type CadFormat = "dwg" | "dxf";
+
+type CadWorkerResponse =
+  | { ok: true; svg: string }
+  | { ok: false; error: string };
+
+const cadFileNamePattern = /\.(dwg|dxf)$/i;
+const maxCadFileBytes = 24 * 1024 * 1024;
+const cadConversionTimeoutMs = 45_000;
+const svgNamespace = "http://www.w3.org/2000/svg";
+const allowedSvgElements = new Set(["svg", "defs", "g", "use", "line", "circle", "path", "polyline", "polygon", "text", "tspan", "pattern", "rect"]);
+const allowedSvgAttributes = new Set([
+  "xmlns",
+  "width",
+  "height",
+  "viewBox",
+  "preserveAspectRatio",
+  "transform",
+  "vector-effect",
+  "stroke",
+  "stroke-width",
+  "stroke-dasharray",
+  "x1",
+  "y1",
+  "x2",
+  "y2",
+  "x",
+  "y",
+  "cx",
+  "cy",
+  "r",
+  "d",
+  "dy",
+  "fill",
+  "points",
+  "patternUnits",
+  "patternTransform",
+  "id",
+  "href",
+  "text-anchor",
+  "alignment-baseline",
+  "visibility",
+  "font-size",
+  "font-family"
+]);
+
+export class CadImportError extends Error {
+  constructor(
+    readonly code: CadImportErrorCode,
+    message: string
+  ) {
+    super(message);
+    this.name = "CadImportError";
+  }
+}
+
+export function isCadFile(file: File) {
+  return cadFileNamePattern.test(file.name);
+}
+
+export function isCanvasImportFile(file: File) {
+  return file.type.startsWith("image/") || /\.(png|jpe?g|webp|gif|avif|svg)$/i.test(file.name) || isCadFile(file);
+}
+
+export function cadImportMessageKey(error: unknown) {
+  if (!(error instanceof CadImportError)) return "cadImportFailed";
+  switch (error.code) {
+    case "too-large":
+      return "cadImportTooLarge";
+    case "timeout":
+      return "cadImportTimeout";
+    case "empty":
+      return "cadImportEmpty";
+    case "unsupported":
+      return "cadImportUnsupported";
+    default:
+      return "cadImportFailed";
+  }
+}
+
+export async function prepareCanvasImportFile(file: File) {
+  if (!isCadFile(file)) return file;
+  if (file.size > maxCadFileBytes) {
+    throw new CadImportError("too-large", "CAD files must be 24 MB or smaller");
+  }
+
+  const format = cadFormat(file.name);
+  const buffer = await file.arrayBuffer();
+  const rawSvg = await convertCadInWorker(buffer, format);
+  const svg = normalizeCadSvg(rawSvg, file.name);
+  const baseName = file.name.replace(/\.(dwg|dxf)$/i, "").trim() || "drawing";
+  return new File([svg], `${baseName} (${format.toUpperCase()}).svg`, {
+    type: "image/svg+xml",
+    lastModified: file.lastModified || Date.now()
+  });
+}
+
+function cadFormat(fileName: string): CadFormat {
+  const extension = fileName.trim().toLowerCase().split(".").pop();
+  if (extension === "dwg" || extension === "dxf") return extension;
+  throw new CadImportError("unsupported", "Only DWG and DXF CAD files are supported");
+}
+
+function convertCadInWorker(buffer: ArrayBuffer, format: CadFormat) {
+  if (typeof Worker === "undefined") {
+    return Promise.reject(new CadImportError("unsupported", "This browser cannot run the CAD converter"));
+  }
+
+  return new Promise<string>((resolve, reject) => {
+    const worker = new Worker(new URL("./cadImport.worker.ts", import.meta.url), { type: "module" });
+    const timeout = window.setTimeout(() => {
+      worker.terminate();
+      reject(new CadImportError("timeout", "CAD conversion timed out"));
+    }, cadConversionTimeoutMs);
+
+    const finish = () => {
+      window.clearTimeout(timeout);
+      worker.terminate();
+    };
+
+    worker.onmessage = (event: MessageEvent<CadWorkerResponse>) => {
+      finish();
+      if (event.data.ok) {
+        resolve(event.data.svg);
+        return;
+      }
+      reject(new CadImportError(event.data.error.includes("no model-space entities") ? "empty" : "conversion", event.data.error));
+    };
+    worker.onerror = (event) => {
+      finish();
+      reject(new CadImportError("conversion", event.message || "CAD conversion worker failed"));
+    };
+    worker.postMessage({ buffer, format }, [buffer]);
+  });
+}
+
+function normalizeCadSvg(rawSvg: string, sourceName: string) {
+  const repairedSvg = repairAnonymousClosingTags(rawSvg);
+  const parsed = new DOMParser().parseFromString(repairedSvg, "image/svg+xml");
+  if (parsed.querySelector("parsererror")) {
+    throw new CadImportError("conversion", "Converted CAD output is not valid SVG");
+  }
+
+  const svg = parsed.documentElement;
+  if (svg.localName !== "svg") {
+    throw new CadImportError("conversion", "Converted CAD output has no SVG root");
+  }
+  sanitizeSvg(svg);
+
+  const viewBox = parseViewBox(svg.getAttribute("viewBox"));
+  if (!viewBox || viewBox.width <= 0 || viewBox.height <= 0) {
+    throw new CadImportError("empty", "CAD drawing has no visible bounds");
+  }
+  if (!svg.querySelector("line,circle,path,polyline,polygon,text,rect")) {
+    throw new CadImportError("empty", "CAD drawing has no supported visible entities");
+  }
+
+  svg.removeAttribute("transform");
+  svg.setAttribute("viewBox", `${formatNumber(viewBox.minX)} ${formatNumber(viewBox.minY)} ${formatNumber(viewBox.width)} ${formatNumber(viewBox.height)}`);
+  svg.setAttribute("preserveAspectRatio", "xMidYMid meet");
+  const preview = cadPreviewSize(viewBox.width, viewBox.height);
+  svg.setAttribute("width", String(preview.width));
+  svg.setAttribute("height", String(preview.height));
+
+  const drawing = parsed.createElementNS(svgNamespace, "g");
+  drawing.setAttribute("transform", `translate(0 ${formatNumber(viewBox.minY * 2 + viewBox.height)}) scale(1 -1)`);
+  Array.from(svg.childNodes).forEach((child) => drawing.appendChild(child));
+  const title = parsed.createElementNS(svgNamespace, "title");
+  title.textContent = sourceName;
+  svg.append(title, drawing);
+
+  return new XMLSerializer().serializeToString(svg);
+}
+
+function repairAnonymousClosingTags(source: string) {
+  const stack: string[] = [];
+  const repaired = source.replace(/<[^>]+>/g, (token) => {
+    if (token.startsWith("<?") || token.startsWith("<!")) return token;
+    if (/^<\/\s*>$/.test(token)) {
+      const name = stack.pop();
+      if (!name) throw new CadImportError("conversion", "CAD SVG contains an unmatched closing element");
+      return `</${name}>`;
+    }
+
+    const closing = token.match(/^<\/\s*([A-Za-z][\w:.-]*)\s*>$/);
+    if (closing) {
+      const name = stack.pop();
+      if (name !== closing[1]) throw new CadImportError("conversion", "CAD SVG contains mismatched elements");
+      return token;
+    }
+
+    const opening = token.match(/^<\s*([A-Za-z][\w:.-]*)\b/);
+    if (opening && !/\/\s*>$/.test(token)) stack.push(opening[1]);
+    return token;
+  });
+  if (stack.length > 0) throw new CadImportError("conversion", "CAD SVG contains unclosed elements");
+  return repaired;
+}
+
+function sanitizeSvg(svg: Element) {
+  removeComments(svg);
+  [svg, ...Array.from(svg.querySelectorAll("*"))].forEach((element) => {
+    if (!allowedSvgElements.has(element.localName)) {
+      element.remove();
+      return;
+    }
+
+    const style = element.getAttribute("style") || "";
+    const fontSize = style.match(/font:\s*([0-9]+(?:\.[0-9]+)?(?:px|mm|cm|in)?)/i)?.[1];
+    Array.from(element.attributes).forEach((attribute) => {
+      if (!allowedSvgAttributes.has(attribute.name)) element.removeAttribute(attribute.name);
+    });
+    if (fontSize && (element.localName === "text" || element.localName === "tspan")) {
+      element.setAttribute("font-size", fontSize);
+      element.setAttribute("font-family", "Noto Sans SC, Helvetica Neue, sans-serif");
+    }
+
+    for (const paintAttribute of ["stroke", "fill"] as const) {
+      const paint = element.getAttribute(paintAttribute)?.trim().toLowerCase();
+      if (paint === "rgb(255,255,255)" || paint === "#fff" || paint === "#ffffff" || paint === "white") {
+        element.setAttribute(paintAttribute, "#16181d");
+      } else if (paint?.includes("url(") && !/^url\(#[^/)]+\)$/.test(paint)) {
+        element.removeAttribute(paintAttribute);
+      }
+    }
+
+    const strokeWidth = element.getAttribute("stroke-width");
+    if (strokeWidth) {
+      const numericWidth = Number.parseFloat(strokeWidth);
+      const pixelWidth = strokeWidth.endsWith("mm") ? numericWidth * 3.7795275591 : numericWidth;
+      if (Number.isFinite(pixelWidth) && pixelWidth < 0.75) element.setAttribute("stroke-width", "0.75");
+    }
+  });
+}
+
+function removeComments(node: Node) {
+  Array.from(node.childNodes).forEach((child) => {
+    if (child.nodeType === 8) child.remove();
+    else removeComments(child);
+  });
+}
+
+function parseViewBox(value: string | null) {
+  const parts = value
+    ?.trim()
+    .split(/[\s,]+/)
+    .map(Number);
+  if (!parts || parts.length !== 4 || parts.some((part) => !Number.isFinite(part))) return null;
+  return { minX: parts[0], minY: parts[1], width: parts[2], height: parts[3] };
+}
+
+function cadPreviewSize(width: number, height: number) {
+  const maxDimension = Math.max(width, height);
+  const displayMax = Math.min(1200, Math.max(480, maxDimension));
+  const scale = displayMax / maxDimension;
+  return {
+    width: Math.max(1, Math.round(width * scale)),
+    height: Math.max(1, Math.round(height * scale))
+  };
+}
+
+function formatNumber(value: number) {
+  return Number(value.toFixed(6)).toString();
+}

frontend/src/ui/lib/cadImport.worker.ts

@@ -0,0 +1,30 @@
+import { convertCadBufferToSvg, type CadFormat } from "./cadConversion";
+
+type CadWorkerRequest = {
+  buffer: ArrayBuffer;
+  format: CadFormat;
+};
+
+type CadWorkerResponse =
+  | { ok: true; svg: string }
+  | { ok: false; error: string };
+
+type WorkerScope = {
+  onmessage: ((event: MessageEvent<CadWorkerRequest>) => void) | null;
+  postMessage: (message: CadWorkerResponse) => void;
+};
+
+const workerScope = globalThis as unknown as WorkerScope;
+
+workerScope.onmessage = (event) => {
+  try {
+    const { buffer, format } = event.data;
+    const svg = convertCadBufferToSvg(buffer, format);
+    workerScope.postMessage({ ok: true, svg });
+  } catch (error) {
+    workerScope.postMessage({
+      ok: false,
+      error: error instanceof Error ? error.message : String(error)
+    });
+  }
+};

frontend/src/ui/lib/vectorImage.ts

@@ -0,0 +1,18 @@
+import type { CanvasNode } from "../../domain/design";
+
+export function isVectorImageNode(node: CanvasNode) {
+  if (node.type !== "image") return false;
+  if (node.layerRole === "vectorized-image" || node.layerRole === "vector-image") return true;
+  return isSvgSource(node.title) || isSvgSource(node.content);
+}
+
+export function isSvgSource(value: string) {
+  const trimmed = value.trim();
+  if (/^data:image\/svg\+xml(?:[;,]|$)/i.test(trimmed)) return true;
+  const path = trimmed.split(/[?#]/, 1)[0] ?? "";
+  try {
+    return decodeURIComponent(path).toLowerCase().endsWith(".svg");
+  } catch {
+    return path.toLowerCase().endsWith(".svg");
+  }
+}

frontend/src/ui/pages/CanvasWorkspace/canvas/WorkspaceToolbar.tsx

@@ -1,6 +1,6 @@
 "use client";
 
-import { Grid3X3, Hand, Hash, Image as ImageIcon, ImageUp, MapPin, MousePointer2, PenLine, Sparkles, Type } from "lucide-react";
+import { FileUp, Grid3X3, Hand, Hash, Image as ImageIcon, MapPin, MousePointer2, PenLine, Sparkles, Type } from "lucide-react";
 import { Popover, PopoverAnchor, PopoverContent } from "@/components/ui/popover";
 import { useI18n } from "@/i18n/i18n";
 import { ShapeToolMenu } from "@/ui/pages/CanvasWorkspace/canvas/ShapeToolMenu";
@@ -20,7 +20,7 @@ export function WorkspaceToolbar({
   onChooseTool,
   onChooseShapeKind,
   onToggleGrid,
-  onUploadImage
+  onUploadAsset
 }: {
   activeTool: CanvasTool;
   canvasToolMenuOpen: boolean;
@@ -34,7 +34,7 @@ export function WorkspaceToolbar({
   onChooseTool: (tool: CanvasTool) => void;
   onChooseShapeKind: (kind: ShapeKind) => void;
   onToggleGrid: () => void;
-  onUploadImage: () => void;
+  onUploadAsset: () => void;
 }) {
   const { t } = useI18n();
   const offsetClass = offsetBy === "files" ? "is-offset-by-files-panel" : offsetBy === "layers" ? "is-offset-by-layers-panel" : "";
@@ -80,8 +80,8 @@ export function WorkspaceToolbar({
       <button disabled={disabled} className={activeTool === "pin" ? "active" : ""} onClick={() => onChooseTool("pin")} aria-label={t("pin")} title={t("pin")}>
         <MapPin size={18} />
       </button>
-      <button disabled={disabled} aria-label={t("uploadImageNode")} title={t("uploadImageNode")} onClick={onUploadImage}>
+      <button disabled={disabled} aria-label={t("uploadCanvasAsset")} title={t("uploadCanvasAsset")} onClick={onUploadAsset}>
-        <ImageUp size={18} />
+        <FileUp size={18} />
       </button>
       <button disabled={disabled} className={showGrid ? "active" : ""} aria-label={t("grid")} title={t("grid")} onClick={onToggleGrid}>
         <Grid3X3 size={18} />

frontend/src/ui/pages/CanvasWorkspace/canvas/nodeExport.ts

@@ -412,11 +412,12 @@ async function exportImageNodeAsSvg(node: CanvasNode) {
 }
 
 async function downloadSvgSource(source: string, title: string) {
+  const fileName = title.toLowerCase().endsWith(".svg") ? title : `${title}.svg`;
   try {
     const blob = await imageBlobForExport(source);
-    downloadBlob(blob, `${title}.svg`, "image/svg+xml");
+    downloadBlob(blob, fileName, "image/svg+xml");
   } catch {
-    downloadOriginalImage(source, title);
+    downloadOriginalImage(source, title.replace(/\.svg$/i, ""));
   }
 }
 

frontend/src/ui/pages/CanvasWorkspace/index.tsx

@@ -38,6 +38,8 @@ import { WorkspaceTitle } from "@/ui/components/WorkspaceTitle";
 import { SharePopover } from "@/ui/components/SharePopover";
 import { autoImageAdjustments, defaultImageAdjustments, parseImageAdjustments, serializeImageAdjustments } from "@/ui/lib/imageAdjustments";
 import { friendlyProjectFailureMessage } from "@/ui/lib/friendlyAgentErrors";
+import { cadImportMessageKey, isCadFile, isCanvasImportFile, prepareCanvasImportFile } from "@/ui/lib/cadImport";
+import { isSvgSource, isVectorImageNode } from "@/ui/lib/vectorImage";
 import { canvasImageUrl } from "@/ui/lib/imageDelivery";
 import { createModelAgentContentPreparer } from "@/ui/lib/modelImageReferences";
 import { visiblePromptText } from "@/ui/lib/promptImageReferences";
@@ -558,7 +560,7 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
   const { showToast } = useGlobalToast();
   const showGenerationError = useCallback((message: string) => showToast(message, "error"), [showToast]);
   const containerRef = useRef<HTMLDivElement | null>(null);
-  const canvasImageInputRef = useRef<HTMLInputElement | null>(null);
+  const canvasAssetInputRef = useRef<HTMLInputElement | null>(null);
   const agentComposerRef = useRef<PromptComposerHandle | null>(null);
   const assistantFeedRef = useRef<HTMLDivElement | null>(null);
   const assistantFooterRef = useRef<HTMLDivElement | null>(null);
@@ -3420,13 +3422,32 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
 
   const uploadImagesToCanvas = async (files: File[], anchor = canvasCenterPoint()) => {
     const currentProject = projectRef.current;
-    const imageFiles = files.filter(isImageFile);
+    const importFiles = files.filter(isCanvasImportFile);
-    if (!currentProject || imageFiles.length === 0) return;
+    if (!currentProject || importFiles.length === 0) return;
 
     setSaving(true);
     setError("");
     const preparedUploads: Array<{ file: File; previewUrl: string; node: CanvasNode }> = [];
     try {
+      const imageFiles: File[] = [];
+      let cadImportCount = 0;
+      let cadImportError: unknown = null;
+      if (importFiles.some(isCadFile)) showCanvasToast(t("cadImportConverting"));
+      for (const file of importFiles) {
+        try {
+          imageFiles.push(await prepareCanvasImportFile(file));
+          if (isCadFile(file)) cadImportCount += 1;
+        } catch (error) {
+          cadImportError ??= error;
+        }
+      }
+      if (cadImportError) {
+        const message = t(cadImportMessageKey(cadImportError));
+        setError(message);
+        showCanvasToast(message, "error");
+      }
+      if (imageFiles.length === 0) return;
+
       for (const [index, file] of imageFiles.entries()) {
         const previewUrl = URL.createObjectURL(file);
         const dimensions = await readImageDimensions(file).catch(() => ({ width: 512, height: 512 }));
@@ -3445,6 +3466,7 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
             height: size.height,
             content: previewUrl,
             tone,
+            layerRole: isSvgSource(file.name) || file.type.toLowerCase().includes("svg") ? "vector-image" : undefined,
             status: "uploading"
           }
         });
@@ -3491,7 +3513,9 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
       const { project: savedProject } = await designGateway.saveCanvas(currentProject.id, viewportRef.current, finalNodes, [], currentProject);
       applyProject(savedProject);
       setDirty(false);
-      if (failedIds.size === 0 && finalUploadedNodeIds.size > 0) showCanvasToast(t("imageUploadSuccess"));
+      if (failedIds.size === 0 && finalUploadedNodeIds.size > 0) {
+        showCanvasToast(cadImportCount > 0 ? t("cadImportSuccess", { count: cadImportCount }) : t("imageUploadSuccess"));
+      }
     } catch (err) {
       preparedUploads.forEach((item) => URL.revokeObjectURL(item.previewUrl));
       const failedUploadIds = new Set(preparedUploads.map((item) => item.node.id));
@@ -3507,7 +3531,7 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
     }
   };
 
-  const handleCanvasImageInput = (event: React.ChangeEvent<HTMLInputElement>) => {
+  const handleCanvasAssetInput = (event: React.ChangeEvent<HTMLInputElement>) => {
     const files = Array.from(event.target.files ?? []);
     event.target.value = "";
     void uploadImagesToCanvas(files);
@@ -3521,7 +3545,7 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
   };
 
   const handleCanvasDragOver = (event: React.DragEvent<HTMLDivElement>) => {
-    if (!dataTransferHasImage(event.dataTransfer)) return;
+    if (!dataTransferHasCanvasFile(event.dataTransfer)) return;
     event.preventDefault();
     event.dataTransfer.dropEffect = "copy";
     setCanvasFileDragging(true);
@@ -3533,7 +3557,7 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
   };
 
   const handleCanvasDrop = (event: React.DragEvent<HTMLDivElement>) => {
-    const files = dataTransferImageFiles(event.dataTransfer);
+    const files = dataTransferCanvasFiles(event.dataTransfer);
     if (files.length === 0) return;
     event.preventDefault();
     event.stopPropagation();
@@ -3586,7 +3610,7 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
           onDragLeave={canEdit ? handleCanvasDragLeave : undefined}
           onDrop={canEdit ? handleCanvasDrop : undefined}
         >
-          <input ref={canvasImageInputRef} type="file" accept="image/*" multiple hidden disabled={!canEdit} onChange={handleCanvasImageInput} />
+          <input ref={canvasAssetInputRef} type="file" accept="image/*,.dwg,.dxf" multiple hidden disabled={!canEdit} onChange={handleCanvasAssetInput} />
           <div className={`workspace-stage-title ${generatedFilesPanelOpen || layersPanelOpen ? "is-offset-by-canvas-panel" : ""}`}>
             <WorkspaceTitle
               title={displayProjectTitle}
@@ -3648,7 +3672,7 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
               messages={project?.messages ?? []}
               selectedIds={selectedIds}
               onSelect={selectOnlyNode}
-              onDownload={(node) => exportImageNode(node, isVectorizedImageNode(node) ? "svg" : "png")}
+              onDownload={(node) => exportImageNode(node, isVectorImageNode(node) ? "svg" : "png")}
               onClose={() => setGeneratedFilesPanelOpen(false)}
             />
           )}
@@ -3773,7 +3797,7 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
 
           {selectedImageNode && selectedNodeBounds && (
             <>
-              {isVectorizedImageNode(selectedImageNode) ? (
+              {isVectorImageNode(selectedImageNode) ? (
                 <VectorizedImageToolbar bounds={selectedNodeBounds} leftInset={floatingToolbarLeftInset} onDownload={() => exportImageNode(selectedImageNode, "svg")} />
               ) : (
                 <>
@@ -4095,7 +4119,7 @@ export function CanvasWorkspace({ projectId, shareAccess = ownerWorkspaceAccess
             onChooseTool={chooseCanvasTool}
             onChooseShapeKind={setSelectedShapeKind}
             onToggleGrid={() => setShowGrid((value) => !value)}
-            onUploadImage={() => canvasImageInputRef.current?.click()}
+            onUploadAsset={() => canvasAssetInputRef.current?.click()}
           />
           {canEdit && activeTool === "pen" && (
             <PenToolControls
@@ -5554,6 +5578,30 @@ function dataTransferHasImage(dataTransfer: DataTransfer) {
   return Array.from(dataTransfer.items).some((item) => item.kind === "file" && item.type.startsWith("image/"));
 }
 
+function dataTransferCanvasFiles(dataTransfer: DataTransfer, fallbackBaseName = "canvas-asset") {
+  const candidates = [
+    ...Array.from(dataTransfer.files),
+    ...Array.from(dataTransfer.items)
+      .filter((item) => item.kind === "file")
+      .map((item) => item.getAsFile())
+      .filter((file): file is File => Boolean(file))
+  ];
+  const seen = new Set<string>();
+  return candidates.filter(isCanvasImportFile).reduce<File[]>((files, file, index) => {
+    const normalizedFile = isImageFile(file) ? ensureImageFileName(file, `${fallbackBaseName}-${Date.now()}-${index + 1}`) : file;
+    const key = `${normalizedFile.name}:${normalizedFile.type}:${normalizedFile.size}:${normalizedFile.lastModified}`;
+    if (seen.has(key)) return files;
+    seen.add(key);
+    files.push(normalizedFile);
+    return files;
+  }, []);
+}
+
+function dataTransferHasCanvasFile(dataTransfer: DataTransfer) {
+  if (dataTransferCanvasFiles(dataTransfer).length > 0) return true;
+  return Array.from(dataTransfer.items).some((item) => item.kind === "file" && item.type.startsWith("image/"));
+}
+
 function ensureImageFileName(file: File, baseName: string) {
   if (file.name.trim()) return file;
   const type = file.type || "image/png";
@@ -5806,10 +5854,6 @@ function visualAnnotationToolLabel(tool: VisualAnnotationTool, t: (key: string)
   return t(keys[tool]);
 }
 
-function isVectorizedImageNode(node: CanvasNode) {
-  return node.type === "image" && node.layerRole === "vectorized-image";
-}
-
 function createOptimisticAgentMessages(threadId: string, contents: AgentContent[]): AgentMessage[] {
   const now = Date.now();
   const promptText = agentContentsToDisplayText(contents);

frontend/tests/cadConversion.test.mjs

@@ -0,0 +1,197 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { BlockRecord, CadDocument, Insert, Line, Point, XYZ } from "@node-projects/acad-ts";
+import { convertCadBufferToSvg, convertCadDocumentToSvg } from "../src/ui/lib/cadConversion.ts";
+
+const r12PointDrawing = `0
+SECTION
+2
+HEADER
+9
+$ACADVER
+1
+AC1009
+0
+ENDSEC
+0
+SECTION
+2
+TABLES
+0
+TABLE
+2
+LTYPE
+70
+1
+0
+LTYPE
+2
+CONTINUOUS
+70
+0
+3
+Solid line
+72
+65
+73
+0
+40
+0.0
+0
+ENDTAB
+0
+TABLE
+2
+LAYER
+70
+1
+0
+LAYER
+2
+0
+70
+0
+62
+7
+6
+CONTINUOUS
+0
+ENDTAB
+0
+ENDSEC
+0
+SECTION
+2
+BLOCKS
+0
+ENDSEC
+0
+SECTION
+2
+ENTITIES
+0
+POINT
+8
+0
+10
+12.5
+20
+8.25
+30
+0.0
+0
+TEXT
+8
+0
+10
+18.0
+20
+14.0
+30
+0.0
+40
+2.5
+1
+R12 label
+0
+ENDSEC
+0
+EOF
+`;
+
+test("converts R12 DXF entities whose colors are inherited from their layer", () => {
+  Object.defineProperty(Point, "name", { configurable: true, value: "a" });
+  const input = new TextEncoder().encode(r12PointDrawing);
+  const buffer = input.buffer.slice(input.byteOffset, input.byteOffset + input.byteLength);
+
+  const svg = convertCadBufferToSvg(buffer, "dxf");
+
+  assert.equal(Point.name, "Point");
+  assert.match(svg, /<circle\b/);
+  assert.match(svg, /<text\b/);
+  assert.match(svg, /fill="rgb\(255,255,255\)"/);
+});
+
+test("emits repeated block inserts as reusable SVG references with full transforms", () => {
+  const document = new CadDocument();
+  const block = new BlockRecord("REPEATED_PART");
+  block.blockEntity.basePoint = new XYZ(2, 3, 0);
+  block.entities.add(new Line(new XYZ(2, 3, 0), new XYZ(12, 3, 0)));
+  document.blockRecords.add(block);
+
+  for (let index = 0; index < 200; index += 1) {
+    const insert = new Insert();
+    insert.block = block;
+    insert.insertPoint = new XYZ(index * 20, 10, 0);
+    insert.xScale = 2;
+    insert.yScale = 3;
+    insert.rotation = Math.PI / 2;
+    document.modelSpace.entities.add(insert);
+  }
+
+  const svg = convertCadDocumentToSvg(document);
+
+  assert.equal((svg.match(/<line\b/g) ?? []).length, 1);
+  assert.equal((svg.match(/<use\b/g) ?? []).length, 200);
+  assert.equal((svg.match(/id="cad-block-/g) ?? []).length, 1);
+  assert.match(svg, /transform="matrix\(0 2 -3 0 9 6\)"/);
+  assert.ok(svg.length < 50_000, `expected reusable output, received ${svg.length} bytes`);
+});
+
+test("expands MINSERT rows and columns without duplicating block geometry", () => {
+  const document = new CadDocument();
+  const block = new BlockRecord("ARRAY_PART");
+  block.entities.add(new Line(new XYZ(0, 0, 0), new XYZ(1, 0, 0)));
+  document.blockRecords.add(block);
+  const insert = new Insert();
+  insert.block = block;
+  insert.columnCount = 3;
+  insert.columnSpacing = 10;
+  insert.rowCount = 2;
+  insert.rowSpacing = 5;
+  document.modelSpace.entities.add(insert);
+
+  const svg = convertCadDocumentToSvg(document);
+
+  assert.equal((svg.match(/<line\b/g) ?? []).length, 1);
+  assert.equal((svg.match(/<use\b/g) ?? []).length, 6);
+  assert.match(svg, /matrix\(1 0 0 1 20 5\)/);
+});
+
+test("cuts cyclic nested block references instead of recursively expanding them", () => {
+  const document = new CadDocument();
+  const first = new BlockRecord("CYCLE_A");
+  const second = new BlockRecord("CYCLE_B");
+  document.blockRecords.add(first);
+  document.blockRecords.add(second);
+  first.entities.add(new Line(new XYZ(0, 0, 0), new XYZ(10, 0, 0)));
+  const firstToSecond = new Insert();
+  firstToSecond.block = second;
+  first.entities.add(firstToSecond);
+  const secondToFirst = new Insert();
+  secondToFirst.block = first;
+  second.entities.add(secondToFirst);
+  const rootInsert = new Insert();
+  rootInsert.block = first;
+  document.modelSpace.entities.add(rootInsert);
+
+  const svg = convertCadDocumentToSvg(document);
+
+  assert.equal((svg.match(/id="cad-block-/g) ?? []).length, 2);
+  assert.equal((svg.match(/<use\b/g) ?? []).length, 2);
+  assert.ok(svg.length < 10_000);
+});
+
+test("excludes invisible CAD entities from output and drawing bounds", () => {
+  const document = new CadDocument();
+  document.modelSpace.entities.add(new Line(new XYZ(0, 0, 0), new XYZ(100, 50, 0)));
+  const invisibleOutlier = new Line(new XYZ(500_000, 500_000, 0), new XYZ(501_000, 501_000, 0));
+  invisibleOutlier.isInvisible = true;
+  document.modelSpace.entities.add(invisibleOutlier);
+
+  const svg = convertCadDocumentToSvg(document);
+
+  assert.equal((svg.match(/<line\b/g) ?? []).length, 1);
+  assert.match(svg, /viewBox="0 0 100 50"/);
+});

frontend/tests/vectorImage.test.mjs

@@ -0,0 +1,28 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { isSvgSource, isVectorImageNode } from "../src/ui/lib/vectorImage.ts";
+
+const imageNode = {
+  id: "node-1",
+  type: "image",
+  title: "image.png",
+  x: 0,
+  y: 0,
+  width: 100,
+  height: 100,
+  content: "/uploads/image.png"
+};
+
+test("recognizes uploaded and CAD-derived SVG image nodes", () => {
+  assert.equal(isVectorImageNode({ ...imageNode, title: "drawing (DWG).svg" }), true);
+  assert.equal(isVectorImageNode({ ...imageNode, content: "/uploads/plan.svg?version=2" }), true);
+  assert.equal(isVectorImageNode({ ...imageNode, content: "data:image/svg+xml,%3Csvg/%3E" }), true);
+  assert.equal(isVectorImageNode({ ...imageNode, layerRole: "vectorized-image" }), true);
+  assert.equal(isVectorImageNode(imageNode), false);
+});
+
+test("recognizes encoded SVG paths without treating raster paths as vector", () => {
+  assert.equal(isSvgSource("https://assets.example.com/%E5%9B%BE%E7%BA%B8.svg#preview"), true);
+  assert.equal(isSvgSource("https://assets.example.com/image.png?format=svg"), false);
+});