Pros of LibreCAD

• Fully open-source and free software, ensuring long-term availability and community-driven development
• Cross-platform compatibility (Windows, macOS, Linux) without limitations
• Active community with frequent updates and contributions

Cons of LibreCAD

• Less polished user interface compared to QCAD
• Fewer advanced features and tools available out-of-the-box
• Steeper learning curve for new users

Code Comparison

QCAD (C++):

RS_Entity* entity = container->firstEntity();
while (entity) {
    if (entity->isVisible() && !entity->isLocked()) {
        // Process entity
    }
    entity = container->nextEntity();
}

LibreCAD (C++):

for (auto entity : *container) {
    if (entity->isVisible() && !entity->getFlag(RS2::FlagLocked)) {
        // Process entity
    }
}

The code snippets show different approaches to iterating through entities. QCAD uses a while loop with explicit pointer manipulation, while LibreCAD employs a more modern range-based for loop. LibreCAD's approach is generally considered more readable and less error-prone.

Pros of FreeCAD

• Full 3D parametric modeling capabilities
• Supports a wider range of CAD applications (mechanical, architectural, etc.)
• More extensive plugin ecosystem and customization options

Cons of FreeCAD

• Steeper learning curve due to more complex features
• Can be slower and more resource-intensive for simpler 2D drafting tasks
• Less focused on traditional 2D CAD workflows

Code Comparison

FreeCAD (Python-based scripting):

import FreeCAD as App
import Part

doc = App.newDocument()
box = Part.makeBox(10, 10, 10)
doc.addObject("Part::Feature", "MyBox").Shape = box
doc.recompute()

QCAD (ECMAScript-based scripting):

include("scripts/Draw/Line/Line2P/Line2P.js");

var line = new Line2P(document);
line.setStartPoint(0, 0);
line.setEndPoint(100, 100);
line.execute();

FreeCAD offers more powerful 3D modeling capabilities and a broader range of applications, while QCAD focuses on efficient 2D drafting. FreeCAD uses Python for scripting, allowing for more complex operations, whereas QCAD uses ECMAScript for simpler 2D drawing tasks.

Pros of OpenSCAD

• Programmatic approach allows for parametric designs and complex geometry
• Text-based format enables version control and collaboration
• Free and open-source software with active community support

Cons of OpenSCAD

• Steeper learning curve for non-programmers
• Limited 2D drafting capabilities compared to traditional CAD software
• Rendering can be slow for complex designs

Code Comparison

OpenSCAD:

module gear(teeth = 20, radius = 5) {
    circle(r = radius);
    for (i = [0:teeth-1]) {
        rotate(i * 360 / teeth) translate([radius, 0, 0]) square([2, 1]);
    }
}
gear();

QCAD (using its scripting API):

var doc = new RDocument();
var circle = new RCircleEntity(doc, new RCircleData(new RVector(0,0), 5));
doc.addEntity(circle);
for (var i = 0; i < 20; i++) {
    var angle = i * 2 * Math.PI / 20;
    var rect = new RRectangleEntity(doc, new RRectangleData(
        new RVector(5 * Math.cos(angle), 5 * Math.sin(angle)), 2, 1, angle));
    doc.addEntity(rect);
}

Pros of KiCad

• More comprehensive EDA suite, including schematic capture, PCB layout, and 3D viewing
• Larger and more active community, resulting in frequent updates and extensive documentation
• Better support for complex, multi-layer PCB designs

Cons of KiCad

• Steeper learning curve due to its more extensive feature set
• Potentially overwhelming for simple 2D CAD tasks
• Larger software footprint and potentially higher system requirements

Code Comparison

KiCad (C++):

void PCB_EDIT_FRAME::OnUpdateLayerPair( wxUpdateUIEvent& aEvent )
{
    LSET visible = GetBoard()->GetVisibleLayers();
    aEvent.Enable( visible.count() >= 2 );
}

QCAD (C++):

void RGraphicsViewImage::updateImage() {
    if (image.isNull()) {
        return;
    }
    graphicsView->scene()->update(boundingRect());
}

KiCad's code snippet demonstrates handling of layer visibility in PCB editing, while QCAD's code focuses on updating graphics views, reflecting their different primary purposes.

Pros of SolveSpace

• 3D parametric modeling capabilities
• Constraint-based sketching system
• Smaller file size and faster performance

Cons of SolveSpace

• Less extensive 2D drafting tools
• Steeper learning curve for new users
• Smaller community and fewer resources

Code Comparison

SolveSpace (C++):

void SolveSpaceUI::MenuFile(Command id) {
    switch(id) {
        case Command::NEW:
            NewFile();
            break;
        case Command::OPEN:
            OpenFile();
            break;
        // ...
    }
}

QCAD (C++):

void QC_ApplicationWindow::slotFileNew() {
    RS_DEBUG->print("QC_ApplicationWindow::slotFileNew()");
    fileNew(false);
}

void QC_ApplicationWindow::slotFileOpen() {
    RS_DEBUG->print("QC_ApplicationWindow::slotFileOpen()");
    fileOpen();
}

Both projects use C++ for their core functionality. SolveSpace employs a more compact switch-case structure for handling menu commands, while QCAD uses individual slot functions for each action. QCAD's code includes debug statements, indicating a focus on easier debugging and maintenance.