CADLib - 3D CAD Library for Sheet Objects

A lightweight C++ CAD library focused on 3D geometry, curves, and sheet surfaces. Designed for compatibility with Qt and C++ visualization frameworks.

Features

• 3D Point Operations: Complete Point3D class with distance calculations and arithmetic operations
• Vector Mathematics: Vector3D class with dot product, cross product, normalization, and angle calculations
• Transformation System: Matrix4x4 for translations, rotations, scaling, and combined transformations
• Curve Support:
  • Line segments
  • Bezier curves (any degree)
  • Parametric curve evaluation and sampling
• Surface Support:
  • Planar surfaces
  • Bezier surfaces (tensor product surfaces)
  • Surface normals and parameter space evaluation
• Qt Compatible: Designed to integrate seamlessly with Qt/C++ visualization

Project Structure

CAD_lib/
├── include/           # Header files
│   ├── Point3D.h
│   ├── Vector3D.h
│   ├── Matrix4x4.h
│   └── Geometry.h
├── src/              # Implementation files
│   ├── Point3D.cpp
│   ├── Vector3D.cpp
│   ├── Matrix4x4.cpp
│   └── Geometry.cpp
├── examples/         # Example programs
│   ├── basic_example.cpp
│   ├── curves_example.cpp
│   ├── surfaces_example.cpp
│   └── transformations_example.cpp
├── cmake/            # CMake configuration
└── CMakeLists.txt    # Build configuration

Building the Library

Prerequisites

• CMake 3.10 or higher
• C++17 compatible compiler (GCC, Clang, MSVC)
• Optional: Qt5 or Qt6 for enhanced integration

Build Instructions

# Create build directory
mkdir build
cd build

# Configure with CMake
cmake ..

# Build the library
cmake --build .

# Optional: Install the library
sudo cmake --install .

Build Options

• BUILD_EXAMPLES: Build example programs (default: ON)

cmake .. -DBUILD_EXAMPLES=OFF

Usage Examples

Basic Point and Vector Operations

#include "Point3D.h"
#include "Vector3D.h"

using namespace CADLib;

// Create points
Point3D p1(1.0, 2.0, 3.0);
Point3D p2(4.0, 5.0, 6.0);

// Calculate distance
double dist = p1.distanceTo(p2);

// Create vectors
Vector3D v1(1.0, 0.0, 0.0);
Vector3D v2(0.0, 1.0, 0.0);

// Vector operations
double dot = v1.dot(v2);
Vector3D cross = v1.cross(v2);
double angle = v1.angleToInDegrees(v2);

Transformations

#include "Matrix4x4.h"

using namespace CADLib;

Point3D point(1.0, 0.0, 0.0);

// Translation
Matrix4x4 translation = Matrix4x4::translation(5.0, 3.0, 2.0);
Point3D translated = translation.transform(point);

// Rotation (90 degrees around Z axis)
Matrix4x4 rotation = Matrix4x4::rotationZ(M_PI / 2);
Point3D rotated = rotation.transform(point);

// Combined transformations
Matrix4x4 combined = translation * rotation;
Point3D transformed = combined.transform(point);

Working with Curves

#include "Geometry.h"

using namespace CADLib;

// Create a cubic Bezier curve
std::vector<Point3D> controlPoints = {
    Point3D(0, 0, 0),
    Point3D(2, 8, 0),
    Point3D(8, 8, 0),
    Point3D(10, 0, 0)
};

BezierCurve curve(controlPoints);

// Evaluate curve at parameter t
Point3D point = curve.pointAt(0.5);
Vector3D tangent = curve.tangentAt(0.5);

// Sample the curve
std::vector<Point3D> samples = curve.sample(20);

// Transform the curve
Matrix4x4 transform = Matrix4x4::rotationZ(M_PI / 4);
curve.transform(transform);

Working with Surfaces

#include "Geometry.h"

using namespace CADLib;

// Create a planar surface
Point3D origin(0, 0, 0);
Vector3D uAxis(1, 0, 0);
Vector3D vAxis(0, 1, 0);
PlanarSurface surface(origin, uAxis, vAxis, 10.0, 5.0);

// Evaluate surface at parameters (u, v)
Point3D point = surface.pointAt(0.5, 0.5);
Vector3D normal = surface.normalAt(0.5, 0.5);

// Create a Bezier surface
std::vector<std::vector<Point3D>> controlNet = {
    {Point3D(0, 0, 0), Point3D(0, 10, 0)},
    {Point3D(10, 0, 0), Point3D(10, 10, 2)}
};

BezierSurface bezier(controlNet);
Point3D surfacePoint = bezier.pointAt(0.5, 0.5);

Integration with Qt

The library is designed to be compatible with Qt. When Qt is detected during build, additional integration features are enabled:

// The library can be linked with Qt projects
// Column-major matrix format matches OpenGL/Qt conventions
Matrix4x4 transform = Matrix4x4::rotationZ(angle);
// Use transform data with QMatrix4x4 or OpenGL

API Overview

Point3D

• Constructors and arithmetic operators
• Distance calculations
• Midpoint calculation
• Transformation support

Vector3D

• Direction and magnitude operations
• Dot and cross products
• Normalization
• Angle calculations
• Projection and reflection

Matrix4x4

• 4x4 transformation matrices
• Translation, rotation, scaling
• Matrix multiplication
• Inversion and transposition
• Column-major storage (OpenGL/Qt compatible)

Geometry Classes

• Geometry: Base class for all geometric entities
• Line: Line segment with closest point and distance calculations
• Curve: Base class for parametric curves
• BezierCurve: Bezier curves of any degree
• Surface: Base class for parametric surfaces
• PlanarSurface: Flat rectangular surfaces
• BezierSurface: Tensor product Bezier surfaces

Running Examples

After building, run the example programs:

# From the build directory
./examples/basic_example
./examples/curves_example
./examples/surfaces_example
./examples/transformations_example

License

This library is provided as-is for educational and commercial use.

Future Enhancements

Potential areas for expansion:

• NURBS curves and surfaces
• Trimmed surfaces
• Boolean operations on sheet objects
• Import/export formats (STEP, IGES)
• Mesh generation from surfaces
• Intersection calculations
• Qt widget for 3D visualization

Contributing

Feel free to extend and modify this library for your CAD applications.