This chapter provides information on how to create basic objects in Facet Modeler.

Facet Modeler enables you to create several body primitives. All functions are declared in the <KERNEL_DIR>/FacetModeler/include/Modeler/FMMdlBody.h header file.

Create a Box

To create a box, use the box() constructor:

static Body box(const OdGePoint3d& ptOrigin, const OdGeVector3d& vSizes);

The following code snippet creates a cube with side length of edgeLen:

Body createCube(double edgeLen)
{
  // Create dimensions vector
  OdGeVector3d dimensions(edgeLen, edgeLen, edgeLen);
   // Move the origin point to the center of the cube base
  OdGeVector3d shift(edgeLen / 2, edgeLen / 2, 0.0);
   return Body::box(OdGePoint3d::kOrigin - shift, dimensions);
}

Create a Pyramid

To create a pyramid, use the pyramid() constructor:

static Body pyramid(const Profile2D& rBase, const OdGePoint3d& ptApex, const DeviationParams& deviation = FMGeGbl::gDefDev);

The following code snippet creates a pyramid based on a polygon with sidesCnt edges inscribed into a circle with a radius dRradius, and with height dHeight:

Body createPyramid(const DeviationParams& devDeviation, double dRadius, double dHeight, unsigned int sidesCnt)
{
  // Create circle for polygon inscribing
  OdGeCircArc2d circle(OdGePoint3d::kOrigin.convert2d(), dRadius);
  OdGePoint2dArray points;
   // Inscribe a polygon in a circle and get vertices
  circle.getSamplePoints(sidesCnt, points);
   // Create base profile
  Profile2D cBase;
   // Only with one contour
  cBase.resize(1);
   // Fill contour with vertices
  cBase.front().appendVertices(points);
   // Close profile
  cBase.front().setClosed();
   // Make contour outer
  cBase.front().makeCCW();
   // Create apex
  OdGePoint3d apex(
    OdGePoint3d::kOrigin.x,
    OdGePoint3d::kOrigin.y,
    OdGePoint3d::kOrigin.z + dHeight
  );
   // Create pyramid
  return Body::pyramid(cBase, apex, devDeviation);
}

Create a Cone

In Facet Modeler a cone is a special type of pyramid. To create a cone, create a circle and use the pyramid() constructor with the circle as rBase:

static Body pyramid(const Profile2D& rBase, const OdGePoint3d& ptApex, const DeviationParams& deviation = FMGeGbl::gDefDev);

The following code snippet creates a cone with a radius dRadius and height dHeight:

Body createCone(const DeviationParams& devDeviation, double dRadius, double dHeight)
{
  // Create base profile
  Profile2D cBase;
   // With one contour
  cBase.resize(1);
   // Add vertices with bulge == 1 (so that they form an arc)
  cBase.front().appendVertex(OdGePoint2d::kOrigin - OdGeVector2d::kXAxis * dRadius, 1);
  cBase.front().appendVertex(OdGePoint2d::kOrigin + OdGeVector2d::kXAxis * dRadius, 1);
   cBase.front().setOrientationAt(0, efoFront);
  cBase.front().setOrientationAt(1, efoFront);
   // Close profile
  cBase.front().setClosed();
   // Make contour outer
  cBase.front().makeCCW();
   // Create apex point
  OdGePoint3d apex(
    OdGePoint3d::kOrigin.x,
    OdGePoint3d::kOrigin.y,
    OdGePoint3d::kOrigin.z + dHeight
  );
   return Body::pyramid(cBase, apex, devDeviation);
}

Create a Mesh Body

In Facet Modeler it is also possible to create a body from a given mesh. To do so, use the createFromMesh() method:

static Body createFromMesh(
  const std::vector& aVertices, 
  const std::vector& aFaceData, 
  const std::vector* aFaceFlags = NULL, 
  const std::vector* aEdgeFlags = NULL, 
  const std::vector* aVertexFlags = NULL, 
  const std::vector* pFaceColors = NULL, 
  const std::vector* pEdgeColors = NULL);

The code snippet below creates a cube from a mesh given in the aFaceData vecotr. As you can see, for convenience, this vector was split into lines. Each line follows this template "n P1 P2 ... Pn", where n represents the number of points that form a face and must be greater than or equal to 3. Index of a point used here is equal to the point's index in aVertices vector. Also it's important to mention that points in aFaceData's line should form a counterclockwise direction.

Body createMeshCube(const DeviationParams& devDeviation)
{
  // Create array of vertices
  OdGePoint3d aVertices[] = {
    OdGePoint3d(0.0, 0.0, 0.0),
    OdGePoint3d(1.0, 0.0, 0.0),
    OdGePoint3d(1.0, 1.0, 0.0),
    OdGePoint3d(0.0, 1.0, 0.0),
    OdGePoint3d(0.0, 0.0, 1.0),
    OdGePoint3d(1.0, 0.0, 1.0),
    OdGePoint3d(1.0, 1.0, 1.0),
    OdGePoint3d(0.0, 1.0, 1.0),
  };
   // Create array with face data
  OdInt32 aFaceData[] = {
    4, 3, 2, 1, 0,
    4, 4, 5, 6, 7,
    4, 2, 3, 7, 6,
    4, 1, 2, 6, 5,
    4, 0, 1, 5, 4,
    4, 3, 0, 4, 7
  };
   Body body = Body::createFromMesh(
    makeVector(aVertices), makeVector(aFaceData)
  );
   return body;
}

Here, makeVector() function is implemented as follows:

template< typename T, size_t N >
std::vector<T> makeVector(const T(&data)[N])
{
  return std::vector<T>(data, data + N);
}

See Also