Spline
This feature is in preview release and is subject to change. 
Open 3D Engine (O3DE), the successor to Lumberyard, is now available in Developer
Preview. Download O3DE 
You can create lines and curves in Lumberyard Editor by using the Spline component,
A spline is a curve that connects two or more specific points. This is useful if you want to animate entities along a spline, such as a road or river.
Spline Properties
The Spline component has the following properties.
Name  Description 

Visible 
The component always appears in the viewport, even if the entity isn't selected. 
Spline Type 
Interpolation type to use between vertices. The component supports the following spline types:

Closed 
Specifies whether a spline is a closed or open loop. 
Granularity 
This property is available only for Bézier and CatmullRom spline types. The number of steps for each segment that are in the spline. A step is one of the many short lines that are arranged to approximate the shape of the curve. A segment is the part of the spline between two vertices. 
Knot Parameterization 
This property is available only for the CatmullRom spline type. Adjusts the curvature and smoothness of the spline. Specify a value to support parameterization. A value of For more information, see Knot Parameterization examples. 
Edit 
Choose Edit and the component is locked for editing. For more information, see Editing Components in the Viewport. 
By default, a Spline component has four vertices that are spaced evenly in a line. The vertex positions are stored in the local space of the entity.
Working with Spline Components
You can move the vertices in the local space of the entity along each axis. Each vertex has a planar, linear, and surface manipulator. Combined, these are called the translation manipulator. You can use the translation manipulator to move the vertices.
To change the vertex positions for a spline

Do one of the following:

In the viewport, doubleclick the spline.

In the Entity Inspector, choose Edit. For more information, see Editing Components in the Viewport.


Do one of the following:

Select a vertex on the component and drag either the blue, green, or red arrow (linear manipulator) or the hollow blue, green, or red square (planar manipulator) to a position.

Select a vertex on the component and drag the yellow point (surface manipulator) to move the vertex.

The manipulators follow the grid snap setting that you can specify in Lumberyard Editor toolbar. For more information, see Using the Top Toolbar.
The manipulators behave correctly if the entity is scaled, but the scaling
must be uniform so that the x, y, and z values match (for example,
2.0
, 2,0
, 2.0
). We recommend that you
use uniform scaling for entities with a Spline
component.
You can also select multiple vertices.
To select multiple vertices on a spline

Hold Ctrl and select the vertices. Selected vertices appear yellow.
Note Currently, you can't click and draw a box around the vertices to select them.
You can also snap a vertex to another position on the terrain.
To snap a vertex to another position

Select a vertex.

Hold Shift+Ctrl and click another position on the terrain. The vertex snaps to that position.
You can also add vertices to the spline.
To add a vertex to a spline

Pause over a line and hold Ctrl. A preview appears where you can add the vertex.

Click to add the vertex to the spline.
You can also delete vertices from the spline.
To delete a vertex from the spline

Hold Alt and pause on a vertex. The vertex appears gray.

Click the vertex to delete it. You can also select a vertex and press Delete.
Note Linear and Bézier splines must have a minimum of two vertices. CatmullRom splines must have a minimum of four vertices.
If you change the spline type, the component is updated to represent the new interpolation method.
Example CatmullRom
The first and last vertices of a CatmullRom spline are only control points. They don't form part of the curve. A wellformed CatmullRom spline must have a minimum of four vertices. The spline doesn't render if there are fewer than four vertices.
The following examples show how CatmullRom splines change when you adjust the Knot Parameterization property.
Example Knot Parameterization = 0
Example Knot Parameterization =1
Example Linear and Bézier Splines
The following examples are linear and Bézier splines with the same vertices but with open and closed loops.
EBus Request Bus Interface
Use the following request functions with the SplineComponentRequestBus
EBus interface to communicate with other components of your game. The
Spline component also uses VertexContainer
functions. For more information, see Vertex Containers.
For more information about using the event bus (EBus) interface, see Working with the Event Bus (EBus) system.
Request Name  Description  Parameters  Return  Scriptable 

GetSpline 
Returns a constant pointer to the underlying spline type. You can use this function to query the spline against raycasts and positions. You can also request information, such as the length of the spline, its position, normal, and tangent at various points along the spline. 
None 
AZ::ConstSplinePtr 
Yes 
ChangeSplineType 
Changes the spline type. The For example,

AZ::u64 
None  Yes 
SetClosed 
Specifies whether the spline forms a closed or open loop. 
Boolean  None  Yes 
Example
The following script uses the request bus interface.
local spline = SplineComponentRequestBus.Event.GetSpline(self.entityId);  GetNearestAddressPosition local posSplineQueryResult = spline:GetNearestAddressPosition(Vector3(0, 0, 0)); posSplineQueryResult.splineAddress posSplineQueryResult.splineAddress.segmentIndex posSplineQueryResult.splineAddress.segmentFraction posSplineQueryResult.distanceSq  GetNearestAddressRay local raySplineQueryResult = spline:GetNearestAddressRay(Vector3(10, 1, 0), Vector3(0, 1, 0)); raySplineQueryResult.splineAddress.segmentIndex raySplineQueryResult.splineAddress.segmentFraction raySplineQueryResult.distanceSq raySplineQueryResult.rayDistance local splineAddressFromDistance = spline:GetAddressByDistance(3.0); local splineAddressFromFraction = spline:GetAddressByFraction(0.75);  Test SplineAddress Constructor (1 param) local splineAddress_1 = SplineAddress(2);  Test SplineAddress Constructor (2 params) local splineAddress_2 = SplineAddress(1, 0); spline:GetPosition(splineAddress_1) spline:GetNormal(splineAddress_1) spline:GetTangent(splineAddress_1) spline:GetLength(splineAddress_1) spline:GetSplineLength() spline:GetSegmentLength(1) spline:GetSegmentCount() spline:GetSegmentGranularity() local aabb = spline:GetAabb(Transform:CreateIdentity()); local closed = spline:IsClosed(); local firstVertex = spline.vertexContainer[1]; local lastVertex = spline.vertexContainer[spline.vertexContainer:Size()];  Attention: You can use the bus interface directly, but here (at the moment at least) indexing will start from 0, not 1 as is the norm in Lua. Instead, you should use the functions directly on the VertexContainer, listed below SplineComponentRequestBus.Event.AddVertex(self.entityId, lastVertex + Vector3(1, 2, 3)); SplineComponentRequestBus.Event.UpdateVertex(self.entityId, 0, firstVertex + Vector3(1, 2, 3)); SplineComponentRequestBus.Event.InsertVertex(self.entityId, spline.vertexContainer:Size()  1, lastVertex + Vector3(1, 2, 3)); SplineComponentRequestBus.Event.ClearVertices(self.entityId); SplineComponentRequestBus.Event.RemoveVertex(self.entityId, spline.vertexContainer:Size()  1);  Prefer these functions  indexing will start from 1 spline.vertexContainer:AddVertex(lastVertex + Vector3(1, 2, 3)); spline.vertexContainer:UpdateVertex(1, firstVertex + Vector3(1, 2, 3)); spline.vertexContainer:InsertVertex(spline.vertexContainer:Size(), lastVertex + Vector3(1, 2, 3)); spline.vertexContainer:ClearVertices(); spline.vertexContainer:RemoveVertex(spline.vertexContainer:Size());