topic Re: ellipticalArc in subWorldDraw in ObjectARX Forum

ellipticalArc in subWorldDraw

PEPANOVAK — Tue, 10 Jan 2017 13:36:44 GMT

Hi,

I need help. I do not know how to use this function - geometry().ellipticalArc.

Thank you.

Adesk::Boolean MyCurve3d::subWorldDraw(AcGiWorldDraw* mode)
{
   assertReadEnabled () ;
   //------ Returning Adesk::kFalse here will force viewportDraw() call
   AcGeLineSeg3d *pGeLine=NULL;
   AcGeCircArc3d *pGeArc=NULL;
   AcGeEntity3d *pObj=NULL;
   AcGePoint3d points[2];
   AcGeEllipArc3d*   pGeEllipArc=NULL;

    mode->subEntityTraits().setColor(256);
   int ij=1;
   for (int i=0; i < geCurves.length(); i++) {
       pObj=(AcGeEntity3d*)geCurves.at(i);
       if (pObj->isKindOf(AcGe::kLineSeg3d)) {
           pGeLine=(AcGeLineSeg3d*)geCurves.at(i);
           points[0]=pGeLine->startPoint();
           points[1]=pGeLine->endPoint();
           mode->subEntityTraits().setSelectionMarker(ij++);
           mode->geometry().worldLine(points);
       } else
       if (pObj->isKindOf(AcGe::kCircArc3d)) {
           pGeArc=(AcGeCircArc3d*)geCurves.at(i);
           AcGePoint3d startpt(pGeArc->startPoint());
           AcGePoint3d endpt(pGeArc->endPoint());
           AcGeVector3d startvec = startpt - pGeArc->center();
           AcGeVector3d endvec = endpt - pGeArc->center();
            double angle = pGeArc->endAng() - pGeArc->startAng();
           mode->subEntityTraits().setSelectionMarker(ij++);
           mode->geometry().circularArc(pGeArc->center(),pGeArc->radius(),pGeArc->normal(),startvec, angle, kAcGiArcSimple);
       } else
       if (pObj->isKindOf(AcGe::kEllipArc3d)) {
           double uhelStart=0, uhelEnd=0;
           mode->subEntityTraits().setSelectionMarker(ij++);
           pGeEllipArc=(AcGeEllipArc3d*)geCurves.at(i);

           AcGePoint3d cen(pGeEllipArc->center());
           AcGePoint3d startpt(pGeEllipArc->startPoint());
           AcGePoint3d endpt(pGeEllipArc->endPoint());

            angStart=pGeEllipArc->startAng();
            angEnd=pGeEllipArc->endAng();

           mode->geometry().ellipticalArc(cen, pGeEllipArc->normal(),pGeEllipArc->majorRadius(),pGeEllipArc->minorRadius(),
                angStart, angEnd, 0, kAcGiArcSimple);

        }
   }

   return (Adesk::kTrue) ;
}

Re: ellipticalArc in subWorldDraw

tbrammer — Tue, 10 Jan 2017 14:43:30 GMT

So you try to draw a 3D arc with geometry().ellipticalArc() that is identical to an AcGeEllipArc3d, right?

At first glance your code looks ok. It seems you are only missing a value for the 7th parameter double tiltDegreeInRads for

virtual Adesk::Boolean ellipticalArc(
    const AcGePoint3d& center,
    const AcGeVector3d& normal,
    double majorAxisLength,
    double minorAxisLength,
    double startDegreeInRads,
    double endDegreeInRads,
    double tiltDegreeInRads,
    AcGiArcType arcType = kAcGiArcSimple
)

I haven't tested it but I would suppose you can calculate it somehow like this:

AcGePlane plane;
pGeEllipArc->getPlane(plane);
double tiltDegreeInRads = pGeEllipArc->minorAxis().angleOnPlane(plane);

Maybe the sign is wrong or you have to use majorAxis() instead of minorAxis(). Please try it yourself.

Re: ellipticalArc in subWorldDraw

PEPANOVAK — Tue, 10 Jan 2017 15:59:40 GMT

Thank you tbrammer for your reply,

but there is also a problem with start and end angle and when elliptical arc is in 3D...

Re: ellipticalArc in subWorldDraw

PEPANOVAK — Tue, 10 Jan 2017 20:49:14 GMT

I got it, thank you.

AcGePoint3d cen(pGeEllipArc->center());
AcGePoint3d startpt(pGeEllipArc->startPoint());
AcGePoint3d endpt(pGeEllipArc->endPoint());
AcGeVector3d startvec = startpt - cen;
AcGeVector3d endvec = endpt - cen;
AcGeVector3d ellNorm=startvec.crossProduct(endvec);
AcGeVector3d arcRef=ellNorm.perpVector();
ellNorm.negate();
double angStart= startvec.angleTo(arcRef,ellNorm);
double angEnd = endvec.angleTo(arcRef,ellNorm);