How to create the center line of Road?

[njlhb]

Hi ,everyone,I am a chinese student,how to create the center line of Road from two parallel lines ?

[Anonymous]

Assuming you already have the two lines.

AcGePoint3d ptStart1 = pLine1->startPoint();
AcGePoint3d ptEnd1 = pLine1->endPoint();
AcGePoint3d ptStart2 = pLine2->startPoint();
AcGePoint3d ptEnd = pLine2->startPoint();

AcGeVector3d vStart = pStart2-pStart1;
AcGeVector3d vEnd = pEnd2-pEnd1;

AcGePoint3d ptStartMid = ptStart1+vStart/2.0;
AcGePoint3d ptEndMid = ptEnd1+vEnd/2.0;

AcDbLine* pMidLine = new AcDbLine( pStartMid, ptEndMid);


Or a more generic approach, if the lines are not always lines, but always
same distance apart (like in a curve)
is to have a look at AcDbCurve::getOffsetCurves


/Matt


wrote in message news:5137173@discussion.autodesk.com...
Hi ,everyone,I am a chinese student,how to create the center line of Road
from two parallel lines ?

[frtfff]

how about to write a few xdata in your lines(including arc or polylines),after that you can filter this data to distinguish other lines.
Lix Xu ,china
Frtfff@sina.com