How to tie a knot

• Draw on the empty canvas to lay a rope. The end of the rope stays selected (blue).
• Pull over: draw across a rope and the new part passes over it.
• Pull under: with a part selected, start the stroke on the far side of a rope. The dashed line shows the part that will pass under everything in between.
• Bight: select the middle of a rope, then draw. A doubled strand is pulled out along the stroke.
• Drag any part of a rope to move it. The rest follows.
• Fix: double-click a part of a rope to hold it in place like a second hand (red). Double-click again to release it.
• Cut: right-click the rope, or pick the Cut tool and tap it.
• Loosen: double-click and hold in a gap, or pick the Loosen tool and press in the gap.
• Tighten pulls the ends of the selected rope (or of every rope) outward until the knot jams. While it runs the button reads Pause. A fixed part stays where it is, so fix a loop you want to keep.
• A part that is both selected and fixed is purple.
• Tap the empty canvas to deselect, then draw to start another rope.

Export

• Picture is the current view. Step-by-step sheet is one numbered picture per stroke, as tying instructions.
• Video records the view until you choose Stop recording, for 30 seconds at most.
• 3D model is the rope as GLB (with its colours and texture) or OBJ (shape only).
• On a phone or tablet each export opens the share sheet; elsewhere it is saved to your downloads.

View

• Mouse: right-drag rotates, Shift-right-drag pans, the wheel zooms.
• Touch: two fingers pan and zoom; pick the Rotate view tool to turn the view.

Keys

• T or Space tighten / pause, Ctrl/Cmd+Z undo, Esc deselect.