3D Charts

MatPlotLibNet includes a full 3D projection pipeline: Projection3D (World → View → NDC → Pixel), DepthQueue3D painter's algorithm, Vec3.FaceNormal face-normal shading via Color.Shade / Color.Modulate extensions, and Svg3DRotationScript for client-side rotation in SVG.

Surface plot

Plt.Create()
    .WithTitle("3D Surface — sinc(r)")
    .WithSize(800, 600)
    .AddSubPlot(1, 1, 1, ax => ax
        .WithCamera(elevation: 35, azimuth: -50, distance: 6.0)
        .WithLighting(dx: 0.5, dy: -0.5, dz: 1.0, ambient: 0.3, diffuse: 0.7)
        .Surface(x, y, z, s =>
        {
            s.ColorMap = ColorMaps.Plasma;
            s.ShowWireframe = false;
            s.Alpha = 1.0;
        }))
    .Save("surface.svg");

3D Scatter

Plt.Create()
    .WithTitle("3D Scatter — Paraboloid")
    .AddSubPlot(1, 1, 1, ax => ax
        .WithCamera(elevation: 25, azimuth: -70)
        .Scatter3D(x, y, z, s => { s.Color = Colors.CornflowerBlue; s.MarkerSize = 5; }))
    .Save("scatter3d.svg");

3D Bar chart with interactive rotation

Plt.Create()
    .WithTitle("3D Bar Chart")
    .With3DRotation()
    .AddSubPlot(1, 1, 1, ax => ax
        .WithCamera(elevation: 25, azimuth: -60)
        .WithLighting(dx: -0.4, dy: -0.8, dz: 0.45)
        .Bar3D(x, y, z, s => { s.Color = Colors.Tomato; s.BarWidth = 0.5; }))
    .Save("bar3d.svg");

The axis frame follows the camera

Any azimuth works, including the ones that swing the cube past the matplotlib default view. The shaded panes, the drawn cube edges, the wall grids and the X/Y/Z tick rows are chosen per render from the camera — the pane is always on the face pointing away from you, and a tick row never ends up behind the data (v1.14.1, #18). Dragging an interactive chart past ±90° re-runs the same selection in the browser, so the frame jumps to the other side exactly as matplotlib's does.

Pane3DConfig colours name the AXIS whose wall they paint, not a fixed side of the cube: LeftWallColor is the X-axis wall, RightWallColor the Y-axis wall, FloorColor the Z floor.

Axis titles place themselves clear of their own tick labels (v1.14.2): the gap is measured from the labels the axis actually draws, so a larger tick font or a custom TickFormatter pushes the title out with it — there is no pad to tune.

Plt.Create()
    .AddSubPlot(1, 1, 1, ax => ax
        .WithCamera(elevation: 30, azimuth: -145)   // outside the default quadrant
        .WithPane3D(p => p with { LeftWallColor = Color.FromHex("#EDF2F7"), Alpha = 0.85 })
        .Bar3D(x, y, z))
    .Save("bar3d-rotated.svg");

Grouped 3D bars

Multiple Bar3D series share depth sorting automatically:

Planar 3D bars

Flat translucent rectangles on discrete Y planes:

Line3D — helix polyline (v1.3.0)

double[] t = Enumerable.Range(0, 200).Select(i => i * 0.1).ToArray();

Plt.Create()
    .WithTitle("Line3D — Helix")
    .With3DRotation()
    .AddSubPlot(1, 1, 1, ax => ax
        .Plot3D(t.Select(v => Math.Cos(v)).ToArray(),
                t.Select(v => Math.Sin(v)).ToArray(),
                t.Select(v => v * 0.15).ToArray(),
                s => { s.Color = Colors.Tab10Blue; s.LineWidth = 1.5; })
        .WithCamera(elevation: 25, azimuth: -60))
    .Save("line3d.svg");

Trisurf3D — Delaunay triangulated surface (v1.3.0)

Plt.Create()
    .WithTitle("Trisurf3D")
    .With3DRotation()
    .AddSubPlot(1, 1, 1, ax => ax
        .Trisurf(x, y, z, s =>
        {
            s.ColorMap = ColorMaps.Viridis;
            s.Alpha = 0.9;
            s.ShowWireframe = true;
        })
        .WithCamera(elevation: 30, azimuth: -45))
    .Save("trisurf.svg");

Contour3D — contour lines in 3D (v1.3.0)

Plt.Create()
    .WithTitle("Contour3D — sinc(r)")
    .With3DRotation()
    .AddSubPlot(1, 1, 1, ax => ax
        .Contour3D(x, y, z, s =>
        {
            s.Levels = 12;
            s.ColorMap = ColorMaps.Coolwarm;
            s.LineWidth = 1.5;
        })
        .WithCamera(elevation: 35, azimuth: -55))
    .Save("contour3d.svg");

Quiver3D — 3D vector field (v1.3.0)

Plt.Create()
    .WithTitle("Quiver3D — 3-D vector field")
    .With3DRotation()
    .AddSubPlot(1, 1, 1, ax => ax
        .Quiver3D(x, y, z, u, v, w,
            s => { s.Color = Colors.Red; s.ArrowLength = 0.25; })
        .WithCamera(elevation: 25, azimuth: -60))
    .Save("quiver3d.svg");

Voxels — volumetric cubes (v1.3.0)

var filled = new bool[6, 6, 6];
// Create an L-shaped structure with a pillar
// ...

Plt.Create()
    .WithTitle("Voxels — face-culled cubes")
    .With3DRotation()
    .AddSubPlot(1, 1, 1, ax => ax
        .Voxels(filled, s => { s.Color = Colors.Orange; s.Alpha = 0.85; })
        .WithCamera(elevation: 30, azimuth: -50))
    .Save("voxels.svg");

Text3D — 3D annotations (v1.3.0)

Plt.Create()
    .WithTitle("Text3D — annotations on a surface")
    .With3DRotation()
    .AddSubPlot(1, 1, 1, ax => ax
        .Surface(x, y, z, s => { s.ColorMap = ColorMaps.Plasma; s.Alpha = 0.7; })
        .Text3D(0, 0, 1.0, "Peak", s => { s.Color = Colors.Red; s.FontSize = 14; })
        .Text3D(-2, -2, -0.5, "Valley", s => { s.Color = Colors.Blue; s.FontSize = 12; })
        .WithCamera(elevation: 35, azimuth: -55))
    .Save("text3d.svg");