Line Segments

Introduction

In geometry, a line segment is a part of a line that is bounded by two distinct end points, and contains every point on the line between its end points. A closed line segment includes both endpoints.

Line segments can be used to approximate smooth curves.

Line Segment Objects

Creating a spring using an list of segments. See example 13-primitives

Similar to mesh objects, line segment models use vertices to describe all the lines that compose the objects. A finger-proxy algorithm is also used to compute all the interaction forces between the haptic tool and the object. A collision detection must also be initialized after all points have been created.

using namespace chai3d;

// create a line segment object
cMultiSegment* segments = new cMultiSegment();

// add object to world
world->addChild(segments);

// connect some segments to form a spring
double h = 0.0;
double dh = 0.001;
double a = 0.0;
double da = 0.2;
double r = 0.05;
for (int i=0; i<200; i++)
{
    double px0 = r * cos(a);
    double py0 = r * sin(a);
    double pz0 = h;

    double px1 = r * cos(a+da);
    double py1 = r * sin(a+da);
    double pz1 = h+dh;

    // create vertex 0
    int index0 = segments->newVertex(px0, py0, pz0);
    
    // create vertex 1
    int index1 = segments->newVertex(px1, py1, pz1);
    
    // create segment by connecting both vertices together
    segments->newSegment(index0, index1);

    h = h + dh;
    a = a + da;
}

// set haptic properties
segments->m_material->setStiffness(0.5 * maxStiffness);

// assign color properties
cColorf color;
color.setYellowGold();
segments->setLineColor(color);

// assign line width
segments->setLineWidth(4.0);

// use display list for faster rendering
segments->setUseDisplayList(true);

// build collision tree
segments->createAABBCollisionDetector(toolRadius);