Open CASCADE Technology 8.0.0 Release Candidate 3

Dmitrii Pasukhin's picture
Dmitrii Pasukhin
Mon, 12/15/2025 - 20:21
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OCCT releases

Release Date: December 2025 Full Release Notes: GitHub Discussion #917

Highlights

Version 8.0.0-rc3 includes 157 improvements over RC2, totaling 290+ changes since 7.9.0.

Key Changes

Area Summary
Math Modernization Deprecated OCCT math functions (ACos, Sin, Sqrt, etc.) in favor of std:: equivalents
Threading Replaced Standard_Mutex with std::mutex across all modules
Performance BSpline cache optimization, TopExp improvements, move semantics for math containers
Data Exchange Stream-based I/O for STEP/STL/VRML, STEP metadata export
API constexpr/noexcept for geometric primitives, standard direction enums

Breaking Changes

Math Functions (Deprecated)

// Before (deprecated)        // After
ACos(x)                       std::acos(x)
Sqrt(x)                       std::sqrt(x)
Sin(x) / Cos(x)               std::sin(x) / std::cos(x)
Abs(x)                        std::abs(x)
Min(a, b) / Max(a, b)         std::min(a, b) / std::max(a, b)

Threading

// Before                              // After
#include <Standard_Mutex.hxx>          #include <mutex>
Standard_Mutex myMutex;                std::mutex myMutex;
Standard_Mutex::Sentry aSentry(m);     std::lock_guard<std::mutex> aLock(m);

Removed Classes

  • OSD_MAllocHook - use platform memory tools
  • PLib_Base, PLib_DoubleJacobiPolynomial - use value types directly
  • TopTools_MutexForShapeProvider - use std::mutex
  • QANCollection package - use GTests

New Features

  • gp_Dir::D enum - Standard directions: X, Y, Z, NX, NY, NZ
  • TCollection_AsciiString::EmptyString() - Efficient empty string access
  • GeomHash/Geom2dHash packages - Hash functions for curves/surfaces
  • DE_Wrapper stream support - Read/write from streams

Bug Fixes

  • Fixed crashes in ShapeUpgrade_UnifySameDomain, BRepBuilderAPI_GTransform, BRepFilletAPI_MakeChamfer
  • Fixed Boolean fuse segfault on loft operations
  • Fixed BRepFilletAPI_MakeFillet::Add hang
  • Fixed STEP import crashes and hangs
  • Fixed mesh stack overflow

Resources