= FDO RFC 59 - Support New FDO Geometry Types =

This page contains a request for comments document (RFC) for the FDO Open Source project.  
More FDO RFCs can be found on the [wiki:FDORfcs RFCs] page.

== Status == 
 
||RFC Template Version||1.1||
||Submission Date||April 10, 2011||
||Last Modified||Greg Boone, April 10, 2011||
||Author||Greg Boone||
||RFC Status||Proposed||
||Implementation Status||Not Ready For Review||
||Proposed Milestone||3.7.0.0||
||Assigned PSC guide(s)||Greg Boone||
||'''Voting History'''||(vote date)||
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== Overview ==

Add support to the FDO Geometry API for additional parametric geometry types: Circles, Elliptical Arcs, Cubic Splines and B-Splines.

== Motivation ==

Since the FDO API will continue to be used by new and existing clients as an interchange format, support is required for additional parametric geometry types. Specifically support for elliptical arc, cubic spline, and bspline segments. This will allow more accurate interchange of parametric geometry from client applications without having to tessellate and either lose or create ad-hoc storage for parametric geometry information.

== Proposed Solution ==

The following new Geometry Segment types will be added to the FDO Geometry API to support an enhanced set of parametric geometry types. 

  -  !CircleSegment
  -  !EllipticalArcSegment
  -  !CubicSplineSegment
  -  BSplineSegment

These types work with/derive from existing types that already exist in the FDO Geometry API. Those classes act as base or sibiling classes for the types being added. The existing types include:

  -  !CurveSegmentAbstract
  -  !ArcSegmentAbstract
  -  !CircularArcSegment
  -  !LineStringSegment

Appendix “A” describes these interfaces in their API form. For additional information of the complete set of FDO Geometry API classes, refer to the online FDO API documentation, starting with the following links: 

  -  FdoIGeometry: http://fdo.osgeo.org/files/fdo/docs/FDO_API/da/da2/class_fdo_i_geometry.htm
  -  FdoICurveSegmentAbstract: http://fdo.osgeo.org/files/fdo/docs/FDO_API/df/d3b/class_fdo_i_curve_segment_abstract.htm


== Implications ==

TBD.

== Test Plan ==

TBD.

== !Funding/Resources ==

Autodesk to provide resources / funding