Switch to 3D mode and select a procedural curtain.
Use the red guide lines and nine anchor handles on the curtain surface.
Drag a left or right handle to change the width of the top, middle, or bottom row symmetrically.
Use middle-column handles to adjust the top or bottom curve and the center bend. Top-row dragging can also change curtain height.
To change only one side, double-click a non-middle left or right handle. Drag the highlighted handle, then press Escape or click outside to exit single-point edit.
Save the plan and refresh once to confirm the curtain shape persists.
Minimum width and height limits prevent the curtain from collapsing to an unusable size.