For some entities, the OCS is equivalent to the WCS, and all points (DXF groups 10-37) are expressed in world coordinates. See the following table.

DXF Reference for OCS provided by Autodesk. The points associated with each entity are expressed in terms of the entity’s own object coordinate system (OCS). The OCS was referred to as ECS in previous releases of AutoCAD.

All points associated with an object are expressed in terms of that object's Object Coordinate System (OCS). For point, line, 3D line, 3D face, 3D polyline, 3D mesh, and dimension objects, the OCS is equivalent to the WCS (the object points are World points).

The extrusion vector defines the OCS, it is a normal vector to the base plane of a planar entity. This base plane is always located in the origin of the WCS . But there are some entities like Ellipse , which have an extrusion vector, but do not establish an OCS.

For some entities, the OCS is equivalent to the WCS, and all points (DXF groups 10-37) are expressed in world coordinates. See the following table.

These are basic graphical entities located in an entity space like the modelspace or a block definition and only support the common graphical attributes. The entities in the following examples are always placed in the xy-plane of the WCS aka the 2D drawing space.

Aug 9, 2014 · Once AutoCAD has established the OCS for a given entity, the OCS works as follows: The elevation value stored with an entity indicates how far to shift the XY plane along the Z axis (from the WCS origin) to make it coincide with the plane that contains the entity.

Aug 28, 2023 · Some entities like INSERT entities have an object coordinate system different from the world coordinate system. I'm using the OCS.to_wcs() function to convert the points into world coordinates. This works almost perfectly.

Entity.Ecs Property Description Accesses a transformation matrix that can be used to transform vectors or points from the object's object coordinate system (OCS) to the World Coordinate System (WCS).

In this series of articles, we talk and demonstrate about OCS (ECS) as far as AutoCAD .NET is concerned. Before, we output the AutoCAD .NET ARC Object Properties directly but found some were inconsistent with what were displayed in the Properties UI, …