From: Harry Mattison

Sent: Wednesday, December 23, 2009 04:26

To: Anthony Hauck; Jeremy Tammik; Scott Conover

Subject: playing pool with FindReferencesByDirection

Attachments: PoolTable.rvt; ClassLibraryC.dll

Hi,

Here's the modification we discussed to make the ray shooting SDK example a bit more fun. Some code cleanup might be in order before publishing it, but it works and can amuse a 6 year old, if nothing else.

Harry

public class RaytraceBouncePool : IExternalCommand {

// have a line style "bounce" created in the document before running this

ExternalCommandData cdata;

Autodesk.Revit.Application app;

Document doc;

Face face = null;

Autodesk.Revit.Geometry.Reference rClosest = null;

Autodesk.Revit.Elements.View3D view = null;

static double epsilon = 0.00000001;

int LineCount = 0;

int RayCount = 0;

public IExternalCommand.Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements) {

cdata = commandData;

app = commandData.Application;

doc = app.ActiveDocument;

Get3DView();

DeleteLines();

// find the cue

XYZ direction = null;

XYZ startpt = null;

List<Autodesk.Revit.Element> list = new List<Autodesk.Revit.Element>();

Filter filter = app.Create.Filter.NewTypeFilter(typeof(Autodesk.Revit.Elements.FamilyInstance));

int num = app.ActiveDocument.get_Elements(filter, list);

foreach (Autodesk.Revit.Element e in list) {

if (e.Name == "cue") {

LocationCurve lc = e.Location as LocationCurve;

direction = lc.Curve.ComputeDerivatives(0,true).BasisX;

startpt = lc.Curve.get_EndPoint(1);

break;

                    }

                }

if (view == null) MessageBox.Show("A default 3D view (named {3D}) must exist before running this command");

else {                       

for (int ctr = 1; ctr <= 100; ctr++) // how many bounces to run

                    {

Autodesk.Revit.Geometry.ReferenceArray references = doc.FindReferencesByDirection(startpt, direction, view);

rClosest = null;

FindClosestReference(references);

if (rClosest == null) {

MessageBox.Show("Ray " + ctr + " aborted. No closest face reference found.");

return IExternalCommand.Result.Succeeded;

                            }

else {

XYZ endpt = new XYZ(rClosest.GlobalPoint.X, rClosest.GlobalPoint.Y, rClosest.GlobalPoint.Z);

if (startpt.AlmostEqual(endpt)) {

MessageBox.Show("Start and end points are equal. Ray " + ctr + " aborted\n" + startpt.X + ", " + startpt.Y + ", " + startpt.Z);

break;

                                }

else {

MakeLine(startpt, endpt, direction, "bounce");

RayCount = RayCount + 1;

face = rClosest.GeometryObject as Face;

if (rClosest.Element.Category.Name == "Doors")

                                    {

MessageBox.Show("You sank the ball with " + ctr + " shots.");

return IExternalCommand.Result.Succeeded;

                                    }

UV endptUV = rClosest.UVPoint;

XYZ FaceNormal = face.ComputeDerivatives(endptUV).BasisZ;  // face normal where ray hits

FaceNormal = rClosest.Transform.OfVector(FaceNormal); // transformation to get it in terms of document coordinates instead of the parent symbol

XYZ directionMirrored = direction - 2 * direction.Dot(FaceNormal) * FaceNormal; //http://www.fvastro.org/presentations/ray_tracing.htm

direction = directionMirrored; // get ready to shoot the next ray

startpt = endpt;

                                }

                            }

                        }

                }

return IExternalCommand.Result.Succeeded;

            }

public Autodesk.Revit.Geometry.Reference FindClosestReference(ReferenceArray references) {

double face_prox = Double.PositiveInfinity;

double edge_prox = Double.PositiveInfinity;

//string refs = "";

foreach (Autodesk.Revit.Geometry.Reference r in references) {

if (r.Element.Category.Name != "Generic Models")

                   {

face = null;

face = r.GeometryObject as Face;

Edge edge = null;

edge = r.GeometryObject as Edge;

if (face != null)

                      {

//refs = refs + r.ProximityParameter + "\n";

if (Math.Abs(r.ProximityParameter) < face_prox && r.ProximityParameter > epsilon) //when startpoint is on a surface, should FindReferencesByDirection find that surface?

                         {

rClosest = r;

face_prox = Math.Abs(r.ProximityParameter);

                         }

                      }

if (edge != null)

                      {

if (Math.Abs(r.ProximityParameter) < edge_prox && r.ProximityParameter > epsilon) //when startpoint is on a surface, should FindReferencesByDirection find that surface?

                         {

edge_prox = Math.Abs(r.ProximityParameter);

                         }

                      }

                   }

                }

//MessageBox.Show("Distance to references found:\n" + refs);

if (edge_prox <= face_prox) rClosest = null; // stop bouncing if there is an edge at least as close as the neareast face - there is no single angle of reflection for a ray striking a line

return rClosest;

            }

public void MakeLine(XYZ startpt, XYZ endpt, XYZ direction, string style) {

LineCount = LineCount + 1;

Line line = app.Create.NewLineBound(startpt, endpt);

Plane geometryPlane = app.Create.NewPlane(direction, startpt);

SketchPlane skplane = app.ActiveDocument.Create.NewSketchPlane(geometryPlane);

ModelCurve mcurve = app.ActiveDocument.Create.NewModelCurve(line, skplane);

ElementArray lsArr = mcurve.LineStyles;

foreach (Autodesk.Revit.Element e in lsArr) {

if (e.Name == style) {

mcurve.LineStyle = e;

break;

                    }

                }

            }

public void Get3DView() {

List<Autodesk.Revit.Element> list = new List<Autodesk.Revit.Element>();

Filter filter = app.Create.Filter.NewTypeFilter(typeof(Autodesk.Revit.Elements.View3D));

Int64 num = app.ActiveDocument.get_Elements(filter, list);

foreach (Autodesk.Revit.Element v in list) {

if (v.Name == "{3D}") {

view = v as Autodesk.Revit.Elements.View3D;

break;

                    }

                }

            }

public void DeleteLines() {

List<Autodesk.Revit.Element> list = new List<Autodesk.Revit.Element>();

Filter filter = app.Create.Filter.NewTypeFilter(typeof(Autodesk.Revit.Elements.CurveElement), true);

Int64 num = app.ActiveDocument.get_Elements(filter, list);

foreach (Autodesk.Revit.Element e in list) {

ModelCurve mc = e as ModelCurve;

if (mc != null) {

if (mc.LineStyle.Name == "bounce" || mc.LineStyle.Name == "normal") app.ActiveDocument.Delete(e);

                    }

                }

            }

        }