Curve2Collision turns a Path2D curve into a thickened CollisionPolygon2D, and keeps it in sync automatically while you edit the curve. Useful for slopes, tubes, rails, cave walls — anything you would rather draw as a line than build vertex by vertex.

Usage

1. Add a StaticBody2D (or AnimatableBody2D for moving platforms, Area2D for detection only) to your scene.
2. Add a CurveCollision2D node as its child. CollisionPolygon2D only works as a direct child of a CollisionObject2D, so this parenting matters — the node shows a configuration warning if it is placed anywhere else.
3. Draw the curve as usual with the curve editing tools.
4. Set thickness. A CollisionPolygon2D named GeneratedCollision is created and updated automatically.

StaticBody2D
├── CurveCollision2D      <- you draw the curve here
└── GeneratedCollision    <- generated CollisionPolygon2D

Properties

Self-intersection

Shapes are built with Godot's own Geometry2D.offset_polyline() / offset_polygon() (Clipper). Even when the thickness is large relative to a tight curve, the self-intersections that appear on the inner side are resolved correctly by the library — the band never pinches or distorts.

With closed_loop enabled, the outer and inner contours are offset separately and stitched into a ring. If the thickness is large enough that the inner contour disappears, the result becomes a solid blob.

Known limitations

• join_type = Round produces smooth corners at the cost of more vertices. Use Miter or Square, or tune tolerance_degrees / max_vertices, if you need it lighter.
• Rectangle and circle frame shapes are not supported — curve-based shapes only.
• Auto-updating many curves at once can slow the editor down. Turn off auto_update and use regenerate_now manually in that case.

Requirements

Godot 4.x. Tested on 4.7.1.

MIT licensed. Source and issues: https://github.com/seina369/godot-curve2collision