Basil Item Design

A thing that is created and managed within Basil is called an “item”. An item can be most anything from a mesh representation to a UI element to a camera view.

Items are just identified containers that can be anything: meshes, animations, cameras. To the container, functionality is added as “able”`s. That is, a mesh item can be positionable, or animatable, or whatever-able.

This is a riff on the entity/component model found in many game engines.

Access to the item’s functionality and the functionality of the “able”s for the item is through “properties” which are simple name/value pairs. Each “able” adds some properties to the item and the item is discovered and operated on by reading and changing the values of the properties.

Every item is an instance of BItem which provides the base properties, item collection management, and the “able” addition, removal, and management. The base properties are:

Property Gettable Settable Desc
_Type yes no One of ??
_Id yes no Unique string identifier for this BItem
_OwnerId yes no Connection/service that created this BItem
_Layer yes no String name of group this BItem belongs to
_Unique yes no A unique item key supplied by the creator or generated if not



This defines a displayable item. It usually is a MeshSet.

Property Gettable Settable Desc
DType yes no One of ??
AABB yes no axis aligned bounding box as “x,y,z,x,y,z”

Other properties depend on the value of “_DisplayableType”:


URL yes no URL needed for loader
LoaderType yes no One of “GLTF”, ??
AssetAuth yes yes token to use for fetching the asset


This ability represents an instance of a displayable in the 3d space. Often, there is a Displayable and Instanceable on a single item – the case where there is a single instance of the displayable asset in the 3d space. There could be a single Displayable item with many Instancable items that reference that displayable. In this latter case, there will not be Displayable properties in this item but, instead, a “DisplayableRef” property will be present.

Property Gettable Settable Desc
Pos yes yes Position as “x,y,z”
Rot yes yes Rotation as “x,y,z,w”
PosCoord yes yes Coordinate system code for “Position”
RotCoord yes yes Coordinate system code for “Rotation”
DisplayRef yes no ID of item with Displayability if not present here