3D surfaces

Plots → 3D Surface (tooltip: insert 3D surface plot z = f(x, y)) places its own region type. You do not type the formula on the plot. Assign z (or any name) on the sheet, then tell the surface which variable to plot and how to sweep its two inputs.

Define z on the sheet

Above the plot, assign a formula in two independent names — commonly x and y:

z := sin(x) * cos(y) =

Those names only need to exist so the plot can sweep them. You do not have to give them a useful single value; the surface substitutes each sample pair during evaluate.

Edit surface

1. Open the Plots tab and choose 3D Surface, then click the page.
2. Click the gear (tooltip: Edit surface) if the panel is closed. The canvas hides while the panel is open.
3. Set the fields below, then click the gear again to draw.
4. Evaluate the sheet so z is in scope.

The panel:

• z variable — the sheet assignment to plot. Hint on the panel: assign a formula on the sheet (e.g. z := sin(x)·cos(y)), then sweep its inputs below.
• x var, x min, x max, x step — independent variable and sample grid. Tooltip on step: spacing between x samples (max 80 points along the axis).
• y var, y min, y max, y step — the same for the second axis (also max 80 points).
• Title — optional; shown on the toolbar (default label is 3D Surface).
• Colors — colorscale: Viridis, Cividis, Portland, Jet, Hot, Earth, Greys.
• Grid lines — tick to draw the mesh.
• Orthographic — parallel projection, no perspective foreshortening (tooltip: Parallel projection — no perspective foreshortening).

Navigate the surface

• With pin mode off (default), drag to orbit, scroll to zoom, and use Plotly’s pan / orbit / home controls on the canvas.
• The pin button (tooltip: Pin mode — click the surface to drop a data callout (off = orbit/pan freely)) toggles pinning. When it is on, click the surface to drop a callout with x, y, z. Click a callout to remove it.
• Right-click the region for Remove all pins.

3D has no Line / Area / Scatter tabs. Resize with the region handles. The surface redraws when you evaluate or when you change the sweep grid. For a 2D line or scatter of the same formula, use 2D plots. The z assignment must sit above the surface in evaluation order.