Open CASCADE Technology 8.0.0 Release Candidate 3 #917

dpasukhi · 2025-12-15T17:15:39Z

dpasukhi
Dec 15, 2025
Maintainer

Open Cascade is delighted to announce the release of Open CASCADE Technology version 8.0.0 Release Candidate 3 to the public.

Overview

Version 8.0.0-rc3 is a candidate release incorporating 157 improvements and bug fixes compared to version 8.0.0-rc2, bringing the total improvements since version 7.9.0 to over 290 changes.

This release focuses on:

Modernization of math functions with migration to C++ standard library
Threading improvements with migration from Standard_Mutex to std::mutex
Performance optimizations across Foundation Classes, especially BSpline computations
API improvements with constexpr/noexcept annotations throughout the codebase
Data Exchange enhancements including stream support and STEP metadata export

What is a Release Candidate

A Release Candidate is a tag on the master branch that has completed all test rounds and is stable to use. Release candidates progress in parallel with maintenance releases, with the difference that maintenance releases remain binary compatible with minor releases and cannot include most improvements. The cycle for a release candidate is planned to be 5-10 weeks, while maintenance releases occur once per quarter.

What's New in OCCT 8.0.0-rc3

Foundation Classes

Math Functions Modernization

Deprecated math global functions in favor of std equivalents #833: The following functions are now deprecated and will be removed in future releases:
- ACos(), ASin(), ATan(), ATan2() → use std::acos, std::asin, std::atan, std::atan2
- Sinh(), Cosh(), Tanh() → use std::sinh, std::cosh, std::tanh
- ASinh(), ACosh(), ATanh() → use std::asinh, std::acosh, std::atanh
- Sqrt(), Log(), Log10(), Exp() → use std::sqrt, std::log, std::log10, std::exp
- Pow(), Abs(), Sign() → use std::pow, std::abs, std::copysign
- Sin(), Cos(), Tan() → use std::sin, std::cos, std::tan
- Floor(), Ceiling(), Round() → use std::floor, std::ceil, std::round
- IntegerPart() → use std::trunc
- Min(), Max() → use std::min, std::max
- NextAfter() → use std::nextafter

Threading Modernization

Replaced Standard_Mutex with std::mutex #766: Migrated from legacy mutex implementation to standard C++ mutexes across all modules:
- Use std::lock_guard or std::unique_lock instead of Standard_Mutex::Sentry
- Use std::mutex instead of Standard_Mutex
- Optional mutex holders now use std::unique_ptr<std::mutex>

Geometric Primitives (`gp`)

Added standard direction enumerations #803: New gp_Dir::D and gp_Dir2d::D enums for standard directions (X, Y, Z, NX, NY, NZ)
Enhanced constructors with constexpr/noexcept #798, #796, #790: Geometric primitives (circles, cones, cylinders, axes) now have constexpr constructors

Strings

Added EmptyString() methods #788: New TCollection_AsciiString::EmptyString() and TCollection_ExtendedString::EmptyString() for efficient empty string access
Optimized TCollection_AsciiString #752: Pre-defined string optimization for better performance

Math Containers

Move semantics for math_Matrix and math_Vector #841: Added move constructors and move assignment operators for efficient container transfers

BSpline Optimizations

Optimized BSpline cache #906, #897: Improved BSpline data containers with constexpr and validation, optimized local calls
Enhanced B-Spline curve computation #855: Performance improvements for curve calculations

Other Foundation Improvements

Optimized Bnd package #839, #856: Bounding box optimizations and fixes
Modernized Bnd_B2 and Bnd_B3 #838: Template-based implementation
Enhanced BVH implementation #842, #858: Generic vector types and transformation tests
Performance improvements for TopExp package #831
Optimized Quantity package #834
Improved NCollection vector constructors #835
Modernized NCollection_SparseArrayBase #804
EigenValuesSearcher improvements #714
Refactored CSLib package with GTests #857
Refactored Extrema package #869
Compile-time sqrt constants #789
Precomputed Jacobi coefficients #778
Constexpr Pascal allocator for PLib::Bin #777
Added precision-related methods in Precision.hxx #811
Angle normalization refactor for ElSLib/ElCLib #813

Modeling Data

New GeomHash and Geom2dHash packages #845: Hash functions for geometric curves and surfaces enabling efficient comparison and caching

Modeling Algorithms

Enhanced periodic curve handling in ChFi3d_Builder #892
Improved parameter validation logic in BSplineCache #829

Shape Healing

Optimized PCurve projection #890
Optimized FixFaceOrientation #584

Data Exchange

Stream Support

Implemented stream support for DE_Wrapper #663: Stream-based read/write methods for STEP, STL, VRML, and other formats with validation utilities

STEP Improvements

STEP General Attributes export #634: Export string metadata as STEP property_definition entities
STEP coordinate system connection points import #779
std::string_view for STEP type names #784: Performance improvement using std::string_view for type recognition
Refactored StepType selection #786
Custom hasher for string_view types in RWStepAP214 #888

Plugin System

Reorganized DE plugin system #696: New Register/UnRegister methods for configuration nodes, DE_MultiPluginHolder for multiple registrations

Visualization

Improved detection of full cylinder/cone parameters #830
Fixed AABB transformation method #735

Build and Configuration

Fixed C++ standard options and NOMINMAX scope #907
Modernized compiler flags for C++17 #867
Updated macOS compiler flags and includes #884
Updated VCPKG version #878
Validated configuration on CMake 3.10+ #762
C++17 version macro #785
Updated .gitignore with explicit allowlist #787

Testing

Migrated QA DRAW tests to GTest #818, #823
Migrated QA NCollection to GTests #709
Added Boolean operation GTests #721
Added ShapeAnalysis_CanonicalRecognition unit tests #720
Added Standard_ArrayStreamBuffer unit tests #708
Added PLib functionality unit tests #705
Covered math module with GTests #684
Enhanced BRepOffsetAPI_ThruSections_Test with B-spline support #891

Bug Fixes

Modeling

Fixed thickness operation regression on circle-to-polygon lofts #889
Fixed ShapeUpgrade_UnifySameDomain crash #876
Fixed BRepBuilderAPI_GTransform face stretch crash #875
Fixed out-of-range access in BSplCLib_Reverse #863
Fixed Boolean fuse segfault on loft #860
Fixed BRepFilletAPI_MakeFillet::Add hang #859
Fixed BRepFilletAPI_MakeChamfer crash #743
Fixed BRepOffsetAPI_MakePipeShell crash #740
Fixed chamfer/fillet crash approaching ellipse #738
Fixed array indexing bug in IntAna_IntQuadQuad::NextCurve #703
Fixed null surface crash in fixshape #623
Fixed null surface crash in UnifySameDomain #624
Fixed Bnd_Box::CornerMax incorrect implementation #664
Fixed memory consumption in BOPAlgo_PaveFiller_6 #864

Shape Healing

Fixed regression after Shape Healing - Optimize FixFaceOrientation #584 #753, #769
Fixed inverted revolved shape import from STEP #699
Reverted BSpline check for ShapeConstruct_ProjectCurveOnSurface #894

Data Exchange

Fixed STEP import crash on empty list #671
Fixed STEPCAFControl_Reader hang #733

Mesh

Fixed stack overflow when meshing #695
Fixed STEP file import crash when visualizing boundary curves #745

Application Framework

Early-return null NamedShape when TNaming_UsedShapes is missing #760

Visualization

Fixed unexpected moving with AIS_ViewCube #727

Draw

Fixed message color mixing #685
Fixed dangerous use of 'cin' #681
Fixed incorrect return-value check for scanf-like functions #680

Migration Guide

Deprecated Math Functions

All OCCT math wrapper functions that duplicate C++ standard library functionality are now deprecated. While they still work, you should migrate to std:: equivalents:

// Before (deprecated)
double angle = ACos(value);
double dist = Sqrt(x*x + y*y);
double result = Max(a, b);
double val = Abs(x);

// After (recommended)
double angle = std::acos(value);
double dist = std::sqrt(x*x + y*y);
double result = std::max(a, b);
double val = std::abs(x);

Complete Mapping

Deprecated Function	Standard Replacement
`ACos(x)`	`std::acos(x)`
`ASin(x)`	`std::asin(x)`
`ATan(x)`	`std::atan(x)`
`ATan2(y, x)`	`std::atan2(y, x)`
`Cos(x)`	`std::cos(x)`
`Sin(x)`	`std::sin(x)`
`Tan(x)`	`std::tan(x)`
`Cosh(x)`	`std::cosh(x)`
`Sinh(x)`	`std::sinh(x)`
`Tanh(x)`	`std::tanh(x)`
`ACosh(x)`	`std::acosh(x)`
`ASinh(x)`	`std::asinh(x)`
`ATanh(x)`	`std::atanh(x)`
`Sqrt(x)`	`std::sqrt(x)`
`Log(x)`	`std::log(x)`
`Log10(x)`	`std::log10(x)`
`Exp(x)`	`std::exp(x)`
`Pow(x, y)`	`std::pow(x, y)`
`Abs(x)`	`std::abs(x)`
`Sign(a, b)`	`std::copysign(a, b)`
`Floor(x)`	`std::floor(x)`
`Ceiling(x)`	`std::ceil(x)`
`Round(x)`	`std::round(x)`
`IntegerPart(x)`	`std::trunc(x)`
`Min(a, b)`	`std::min(a, b)`
`Max(a, b)`	`std::max(a, b)`
`NextAfter(x, y)`	`std::nextafter(x, y)`

Note: ACosApprox() is also deprecated; use std::acos() instead.

Standard_Mutex Migration

Replace legacy mutex usage with standard C++ threading primitives:

// Before
#include <Standard_Mutex.hxx>

Standard_Mutex myMutex;
Standard_Mutex::Sentry aSentry(myMutex);
// or
myMutex.Lock();
// ... critical section ...
myMutex.Unlock();

// After
#include <mutex>

std::mutex myMutex;
std::lock_guard<std::mutex> aLock(myMutex);
// or for more control:
std::unique_lock<std::mutex> aLock(myMutex);

For optional/heap-allocated mutexes:

// Before
Standard_Mutex* myOptionalMutex;

// After
std::unique_ptr<std::mutex> myOptionalMutex;

PLib_Base Removal

PLib_Base abstract base class has been removed. PLib_JacobiPolynomial and PLib_HermitJacobi are now value types (not Handle-based):

// Before
Handle(PLib_JacobiPolynomial) aJacobi = new PLib_JacobiPolynomial(...);
aJacobi->D0(...);

// After
PLib_JacobiPolynomial aJacobi(...);
aJacobi.D0(...);  // Note: method is now const

PLib_DoubleJacobiPolynomial Removal

The PLib_DoubleJacobiPolynomial class has been completely removed. If you were using it, you'll need to refactor your code to use PLib_JacobiPolynomial directly.

TopTools_MutexForShapeProvider Removal

The TopTools_MutexForShapeProvider class has been removed. Use std::mutex with shape providers directly.

OSD_MAllocHook Removal

The OSD_MAllocHook class and the Draw command mallochook have been removed. Use platform-specific memory debugging tools instead (Valgrind, AddressSanitizer, etc.).

QANCollection Package Removal

The QANCollection package (test utilities for collections) has been removed. Use GTest-based tests in src/*/GTests/ directories instead.

Transfer_TransferDeadLoop Deprecation

The Transfer_TransferDeadLoop exception class is deprecated. Dead loop detection now uses local status flags instead of exceptions. The class is kept for backward compatibility but should not be used in new code.

StepData_ReadWriteModule::StepType() API Change

The StepType() method now returns const std::string_view& instead of TCollection_AsciiString:

// Before
TCollection_AsciiString aType = aModule->StepType(aTypeNum);

// After
const std::string_view& aType = aModule->StepType(aTypeNum);
// If you need TCollection_AsciiString:
TCollection_AsciiString aTypeStr(aType.data(), static_cast<int>(aType.length()));

Using Standard Direction Enumerations

New convenient enumerations for standard directions:

// Before
gp_Dir aDir(1.0, 0.0, 0.0);  // X direction
gp_Dir aNegZ(0.0, 0.0, -1.0); // Negative Z

// After
gp_Dir aDir(gp_Dir::D::X);   // X direction
gp_Dir aNegZ(gp_Dir::D::NZ); // Negative Z

// Available: X, Y, Z, NX, NY, NZ for gp_Dir
// Available: X, Y, NX, NY for gp_Dir2d

Empty String Access

Use the new static methods for efficient empty string access:

// Before
TCollection_AsciiString anEmpty;
const TCollection_AsciiString& GetEmpty() { static TCollection_AsciiString s; return s; }

// After
const TCollection_AsciiString& anEmpty = TCollection_AsciiString::EmptyString();
const TCollection_ExtendedString& anEmptyExt = TCollection_ExtendedString::EmptyString();

Removed Functionality

Item	Commit	Replacement
`OSD_MAllocHook` class	#707	Platform memory tools
`PLib_Base` class	#795	Direct value types
`PLib_DoubleJacobiPolynomial`	#781	`PLib_JacobiPolynomial`
`TopTools_MutexForShapeProvider`	#766	`std::mutex`
`QANCollection` package	#718	GTests
`Standard_Mutex` (effectively)	#766	`std::mutex`

Deprecated Functionality

Item	Commit	Replacement
Math global functions (`ACos`, `Sin`, etc.)	#833	`std::` equivalents
`ACosApprox()`	#833	`std::acos()`
`Transfer_TransferDeadLoop` exception	#817	Status flags

Performance Improvements Summary

BSpline cache optimized for local calls #906
BSpline data containers with constexpr and validation #897
PCurve projection optimization #890
BndLib optimization #856
Bnd package optimization and fixes #839
B-Spline curve computation enhancement #855
Quantity package optimization #834
TopExp package performance improvements #831
AsciiString optimization with pre-defined strings #752
FixFaceOrientation optimization #584
EigenValuesSearcher improvements #714
Math container optimization #717
Move semantics for math_Matrix/math_Vector #841
Precomputed Jacobi coefficients #778
Constexpr Pascal allocator for PLib::Bin #777
STEP type recognition using std::string_view #784

Documentation

Extensive documentation improvements including:

Whitespace and typo fixes across the codebase #806-#824
Comment uniformity improvements #767, #771
Updated AI Assistant guidelines #854
TCollection documentation update #665

Acknowledgments

We thank all contributors who helped make this release possible through their code contributions, bug reports, and testing.

New Contributors

@sander-adamson-cloudnc made their first contribution in 0033894: fix null surface crash in unifysamedom #624
@petrasvestartas made their first contribution in 0033896 - STEP Write - General Attributes #634
@Rodrigo-BLyra made their first contribution in Visualization - Fix method to transform AABB #735
@gsegon made their first contribution in Coding - Add RTTI support for TFunction_Logbook class #741

Full Changelog: V8_0_0_rc2...V8_0_0_rc3

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Open CASCADE Technology 8.0.0 Release Candidate 3 #917

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Open CASCADE Technology 8.0.0 Release Candidate 3 #917

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dpasukhi Dec 15, 2025 Maintainer

Overview

What is a Release Candidate

What's New in OCCT 8.0.0-rc3

Foundation Classes

Math Functions Modernization

Threading Modernization

Geometric Primitives (gp)

Strings

Math Containers

BSpline Optimizations

Other Foundation Improvements

Modeling Data

Modeling Algorithms

Shape Healing

Data Exchange

Stream Support

STEP Improvements

Plugin System

Visualization

Build and Configuration

Testing

Bug Fixes

Modeling

Shape Healing

Data Exchange

Mesh

Application Framework

Visualization

Draw

Migration Guide

Deprecated Math Functions

Complete Mapping

Standard_Mutex Migration

PLib_Base Removal

PLib_DoubleJacobiPolynomial Removal

TopTools_MutexForShapeProvider Removal

OSD_MAllocHook Removal

QANCollection Package Removal

Transfer_TransferDeadLoop Deprecation

StepData_ReadWriteModule::StepType() API Change

Using Standard Direction Enumerations

Empty String Access

Removed Functionality

Deprecated Functionality

Performance Improvements Summary

Documentation

Acknowledgments

New Contributors

Replies: 0 comments

dpasukhi
Dec 15, 2025
Maintainer

Geometric Primitives (`gp`)