# Curve3D¶

Inherits: Resource < Reference < Object

Category: Core

## Brief Description¶

Describes a Bezier curve in 3D space.

## Methods¶

 void add_point ( Vector3 position, Vector3 in=Vector3( 0, 0, 0 ), Vector3 out=Vector3( 0, 0, 0 ), int at_position=-1 ) void clear_points ( ) float get_baked_length ( ) const PoolVector3Array get_baked_points ( ) const PoolRealArray get_baked_tilts ( ) const PoolVector3Array get_baked_up_vectors ( ) const float get_closest_offset ( Vector3 to_point ) const Vector3 get_closest_point ( Vector3 to_point ) const int get_point_count ( ) const Vector3 get_point_in ( int idx ) const Vector3 get_point_out ( int idx ) const Vector3 get_point_position ( int idx ) const float get_point_tilt ( int idx ) const Vector3 interpolate ( int idx, float t ) const Vector3 interpolate_baked ( float offset, bool cubic=false ) const Vector3 interpolate_baked_up_vector ( float offset, bool apply_tilt=false ) const Vector3 interpolatef ( float fofs ) const void remove_point ( int idx ) void set_point_in ( int idx, Vector3 position ) void set_point_out ( int idx, Vector3 position ) void set_point_position ( int idx, Vector3 position ) void set_point_tilt ( int idx, float tilt ) PoolVector3Array tessellate ( int max_stages=5, float tolerance_degrees=4 ) const

## Description¶

This class describes a Bezier curve in 3D space. It is mainly used to give a shape to a Path, but can be manually sampled for other purposes.

It keeps a cache of precalculated points along the curve, to speed further calculations up.

## Property Descriptions¶

 Setter set_bake_interval(value) Getter get_bake_interval()

The distance in meters between two adjacent cached points. Changing it forces the cache to be recomputed the next time the get_baked_points or get_baked_length function is called. The smaller the distance, the more points in the cache and the more memory it will consume, so use with care.

• bool up_vector_enabled
 Setter set_up_vector_enabled(value) Getter is_up_vector_enabled()

If `true`, the curve will bake up vectors used for orientation. This is used when a PathFollow.rotation_mode is set to `ROTATION_ORIENTED`, see PathFollow for details. Changing it forces the cache to be recomputed.

## Method Descriptions¶

• void add_point ( Vector3 position, Vector3 in=Vector3( 0, 0, 0 ), Vector3 out=Vector3( 0, 0, 0 ), int at_position=-1 )

Adds a point to a curve, at `position`, with control points `in` and `out`.

If `at_position` is given, the point is inserted before the point number `at_position`, moving that point (and every point after) after the inserted point. If `at_position` is not given, or is an illegal value (`at_position <0` or `at_position >= [method get_point_count]`), the point will be appended at the end of the point list.

• void clear_points ( )

Removes all points from the curve.

• float get_baked_length ( ) const

Returns the total length of the curve, based on the cached points. Given enough density (see bake_interval), it should be approximate enough.

Returns the cache of points as a PoolVector3Array.

Returns the cache of tilts as a PoolRealArray.

Returns the cache of up vectors as a PoolVector3Array.

If up_vector_enabled is `false`, the cache will be empty.

Returns the closest offset to `to_point`. This offset is meant to be used in interpolate_baked or interpolate_baked_up_vector.

`to_point` must be in this curve's local space.

Returns the closest point (in curve's local space) to `to_point`.

`to_point` must be in this curve's local space.

• int get_point_count ( ) const

Returns the number of points describing the curve.

Returns the position of the control point leading to the vertex `idx`. If the index is out of bounds, the function sends an error to the console, and returns `(0, 0, 0)`.

Returns the position of the control point leading out of the vertex `idx`. If the index is out of bounds, the function sends an error to the console, and returns `(0, 0, 0)`.

Returns the position of the vertex `idx`. If the index is out of bounds, the function sends an error to the console, and returns `(0, 0, 0)`.

• float get_point_tilt ( int idx ) const

Returns the tilt angle in radians for the point `idx`. If the index is out of bounds, the function sends an error to the console, and returns `0`.

Returns the position between the vertex `idx` and the vertex `idx + 1`, where `t` controls if the point is the first vertex (`t = 0.0`), the last vertex (`t = 1.0`), or in between. Values of `t` outside the range (`0.0 >= t <=1`) give strange, but predictable results.

If `idx` is out of bounds it is truncated to the first or last vertex, and `t` is ignored. If the curve has no points, the function sends an error to the console, and returns `(0, 0, 0)`.

Returns a point within the curve at position `offset`, where `offset` is measured as a pixel distance along the curve.

To do that, it finds the two cached points where the `offset` lies between, then interpolates the values. This interpolation is cubic if `cubic` is set to true, or linear if set to false.

Cubic interpolation tends to follow the curves better, but linear is faster (and often, precise enough).

• Vector3 interpolate_baked_up_vector ( float offset, bool apply_tilt=false ) const

Returns an up vector within the curve at position `offset`, where `offset` is measured as a distance in 3D units along the curve.

To do that, it finds the two cached up vectors where the `offset` lies between, then interpolates the values. If `apply_tilt` is `true`, an interpolated tilt is applied to the interpolated up vector.

If the curve has no up vectors, the function sends an error to the console, and returns `(0, 1, 0)`.

Returns the position at the vertex `fofs`. It calls interpolate using the integer part of `fofs` as `idx`, and its fractional part as `t`.

• void remove_point ( int idx )

Deletes the point `idx` from the curve. Sends an error to the console if `idx` is out of bounds.

Sets the position of the control point leading to the vertex `idx`. If the index is out of bounds, the function sends an error to the console.

• void set_point_out ( int idx, Vector3 position )

Sets the position of the control point leading out of the vertex `idx`. If the index is out of bounds, the function sends an error to the console.

• void set_point_position ( int idx, Vector3 position )

Sets the position for the vertex `idx`. If the index is out of bounds, the function sends an error to the console.

• void set_point_tilt ( int idx, float tilt )

Sets the tilt angle in radians for the point `idx`. If the index is out of bounds, the function sends an error to the console.

The tilt controls the rotation along the look-at axis an object traveling the path would have. In the case of a curve controlling a PathFollow, this tilt is an offset over the natural tilt the PathFollow calculates.

Returns a list of points along the curve, with a curvature controlled point density. That is, the curvier parts will have more points than the straighter parts.

This approximation makes straight segments between each point, then subdivides those segments until the resulting shape is similar enough.

`max_stages` controls how many subdivisions a curve segment may face before it is considered approximate enough. Each subdivision splits the segment in half, so the default 5 stages may mean up to 32 subdivisions per curve segment. Increase with care!

`tolerance_degrees` controls how many degrees the midpoint of a segment may deviate from the real curve, before the segment has to be subdivided.