From bd1bb1a77c6cd276fbee9116be720f5e0450e0c6 Mon Sep 17 00:00:00 2001 From: wangruiguo Date: Thu, 3 Sep 2026 18:44:57 +0800 Subject: [PATCH] =?UTF-8?q?=E6=96=B0=E5=A2=9E:=20OCCT=20=E8=BD=AC=E6=8D=A2?= =?UTF-8?q?=E6=9C=8D=E5=8A=A1(STEP=E2=86=92glTF=20=E8=BD=BB=E9=87=8F?= =?UTF-8?q?=E5=8C=96=E5=90=8E=E7=AB=AF,=208090=20=E7=AB=AF=E5=8F=A3,=20?= =?UTF-8?q?=E9=9B=B6=E6=96=B0=E4=BE=9D=E8=B5=96)?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit --- occt-service/README.md | 41 ++++++++ occt-service/occt_service.py | 165 +++++++++++++++++++++++++++++++++ occt-service/start-service.bat | 5 + 3 files changed, 211 insertions(+) create mode 100644 occt-service/README.md create mode 100644 occt-service/occt_service.py create mode 100644 occt-service/start-service.bat diff --git a/occt-service/README.md b/occt-service/README.md new file mode 100644 index 0000000..a59aec3 --- /dev/null +++ b/occt-service/README.md @@ -0,0 +1,41 @@ +# OCCT 转换服务 + +把 STEP 文件转成 glTF/GLB，供网页 3D 轻量化预览用。**只做转换，不做参数化建模**（升级 2 已决策不做）。 + +## 依赖 + +- Python 3.x +- `OCP`（OpenCASCADE Python 绑定，本机已验证可用） + +## 启动 + +``` +start-service.bat +``` + +或命令行：`python occt_service.py`（端口默认 8090，可用环境变量 `OCCT_PORT` 改）。 + +## 接口 + +| 接口 | 方法 | 说明 | +|---|---|---| +| `/health` | GET | 存活探测 → `{"ok":true,"port":8090}` | +| `/convert` | POST | 请求体 = STEP 文件二进制，query `deflection=0.5`（弦偏差，越大越轻）→ 返回 GLB 二进制 | + +## 调用示例 + +```bash +curl -X POST --data-binary @model.step "http://localhost:8090/convert?deflection=0.5" -o model.glb +``` + +## 设计说明 + +- 零新依赖：HTTP 用标准库 `http.server`，几何用 OCP。 +- 单线程：OCP 非线程安全，避免并发崩溃。 +- 临时文件用完即删，不落盘。 +- deflection 默认 0.5mm（屏幕预览够用，体积小）；要更精细可调小到 0.1，要更小可调大到 2.0。 + +## 与主项目的关系 + +- 这是升级 1（网页 3D 轻量化）的转换后端，独立进程、独立端口，不依赖 NX。 +- 生产部署时可放服务器（服务器无需装 NX，OCP 是纯 Python 库）。 diff --git a/occt-service/occt_service.py b/occt-service/occt_service.py new file mode 100644 index 0000000..053f0f6 --- /dev/null +++ b/occt-service/occt_service.py @@ -0,0 +1,165 @@ +# -*- coding: utf-8 -*- +""" +OCCT 转换服务（常驻 HTTP，默认端口 8090） + +只做一件事：读 STEP 文件 → 三角化 → 导出 glTF/GLB（网页 3D 轻量化用）。 +零新依赖：HTTP 用标准库 http.server，几何内核用 OCP（OpenCASCADE Python 绑定）。 + +接口： + GET /health 存活探测 → {"ok":true,"port":8090} + POST /convert 请求体 = STEP 文件二进制（raw body）， + query 参数 deflection=弦偏差(默认 0.5) → 返回 GLB 二进制 + 失败返回 JSON {"error": "..."} + +说明： + - 单线程 HTTPServer：OCP 是 C++ 绑定、非线程安全，避免并发导致崩溃。 + - 每次转换写临时文件，转换完清理。 + - 本服务只做「STEP→glTF」转换，不做参数化建模（升级2 已决策不做）。 +""" +import os +import sys +import time +import tempfile +from http.server import HTTPServer, BaseHTTPRequestHandler +from urllib.parse import urlparse, parse_qs + +from OCP.STEPControl import STEPControl_Reader +from OCP.BRepMesh import BRepMesh_IncrementalMesh +from OCP.IFSelect import IFSelect_RetDone +# XCAF（glTF 导出用） +from OCP.XCAFApp import XCAFApp_Application +from OCP.TCollection import TCollection_ExtendedString +from OCP.TDocStd import TDocStd_Document +from OCP.XCAFDoc import XCAFDoc_DocumentTool, XCAFDoc_ShapeTool +from OCP.RWGltf import RWGltf_CafWriter +from OCP.TColStd import TColStd_IndexedDataMapOfStringString +from OCP.Message import Message_ProgressRange + +PORT = int(os.environ.get("OCCT_PORT", "8090")) + + +def read_step(path): + """读 STEP 文件 → TopoDS_Shape""" + reader = STEPControl_Reader() + status = reader.ReadFile(path) + if status != IFSelect_RetDone: + raise RuntimeError("STEP 读取失败 status=%s" % status) + reader.TransferRoots() + return reader.OneShape() + + +def tessellate(shape, deflection): + """三角化（弦偏差 deflection 控制精度/体积平衡）""" + mesh = BRepMesh_IncrementalMesh(shape, deflection, False, 0.5, True) + mesh.Perform() + return shape + + +def export_glb(shape, out_path, deflection=0.5): + """shape → 二进制 GLB（经 XCAF 文档承载）""" + tessellate(shape, deflection) + app = XCAFApp_Application.GetApplication_s() + doc = TDocStd_Document(TCollection_ExtendedString("XmlOcaf")) + app.InitDocument(doc) + st = XCAFDoc_DocumentTool.ShapeTool_s(doc.Main()) + lbl = st.NewShape() + st.SetShape(lbl, shape) + w = RWGltf_CafWriter(out_path, True) # True = 二进制 GLB + info = TColStd_IndexedDataMapOfStringString() + prog = Message_ProgressRange() + return w.Perform(doc, info, prog) + + +class Handler(BaseHTTPRequestHandler): + server_version = "occt-service/1.0" + + def log_message(self, fmt, *args): + sys.stderr.write("[%s] %s\n" % (time.strftime("%H:%M:%S"), fmt % args)) + + def _json(self, code, obj): + import json + body = json.dumps(obj).encode("utf-8") + self.send_response(code) + self.send_header("Content-Type", "application/json; charset=utf-8") + self.send_header("Content-Length", str(len(body))) + self.end_headers() + self.wfile.write(body) + + def _send_glb(self, path): + size = os.path.getsize(path) + self.send_response(200) + self.send_header("Content-Type", "model/gltf-binary") + self.send_header("Content-Disposition", 'attachment; filename="model.glb"') + self.send_header("Content-Length", str(size)) + self.end_headers() + with open(path, "rb") as f: + while True: + chunk = f.read(65536) + if not chunk: + break + self.wfile.write(chunk) + + def do_GET(self): + path = urlparse(self.path).path + if path == "/health": + self._json(200, {"ok": True, "port": PORT}) + else: + self._json(404, {"error": "not_found"}) + + def do_POST(self): + parsed = urlparse(self.path) + if parsed.path != "/convert": + self._json(404, {"error": "not_found"}) + return + qs = parse_qs(parsed.query) + deflection = 0.5 + if "deflection" in qs: + try: + deflection = float(qs["deflection"][0]) + deflection = max(0.05, min(10.0, deflection)) + except ValueError: + pass + # 读 raw body（整个请求体 = STEP 文件） + length = int(self.headers.get("Content-Length", "0")) + if length == 0: + self._json(400, {"error": "empty_body"}) + return + data = self.rfile.read(length) + + tmp_step = tempfile.mktemp(suffix=".step") + tmp_glb = tempfile.mktemp(suffix=".glb") + try: + with open(tmp_step, "wb") as f: + f.write(data) + t0 = time.time() + shape = read_step(tmp_step) + ok = export_glb(shape, tmp_glb, deflection) + if not ok: + self._json(500, {"error": "gltf_export_failed"}) + return + elapsed = time.time() - t0 + self.log_message("convert OK %.2fs deflection=%.2f size=%d", elapsed, deflection, os.path.getsize(tmp_glb)) + self._send_glb(tmp_glb) + except Exception as e: + self._json(500, {"error": str(e)[:200]}) + finally: + for p in (tmp_step, tmp_glb): + try: + if os.path.exists(p): + os.remove(p) + except OSError: + pass + + +def main(): + server = HTTPServer(("0.0.0.0", PORT), Handler) + sys.stderr.write("OCCT 转换服务已启动: http://0.0.0.0:%d (/convert, /health)\n" % PORT) + sys.stderr.flush() + try: + server.serve_forever() + except KeyboardInterrupt: + sys.stderr.write("\n服务已停止\n") + + +if __name__ == "__main__": + main() diff --git a/occt-service/start-service.bat b/occt-service/start-service.bat new file mode 100644 index 0000000..a68325e --- /dev/null +++ b/occt-service/start-service.bat @@ -0,0 +1,5 @@ +@echo off +cd /d "%~dp0" +echo Starting OCCT conversion service on port 8090 ... +python occt_service.py +pause