/// <summary>
/// Adds a plate to the node if it is a 'sharp' node, to improve convex hull shape.
/// </summary>
/// <param name="nodeIndex"> Index of the node we want to check/fix. </param>
/// <param name="sides"> Number of sides on the sleeve meshes. </param>
public void FixSharpNodes(int nodeIndex, int sides)
{
ExoHull node = this.Hulls[nodeIndex];
// The extra plate is in the direction of the negative sum of all normals
// We use the new plate normal to check if the node struts are contained
// within a 180deg peripheral (i.e. the node is 'sharp')
bool isSharp = true;
// Sum of all normals
Vector3d extraNormal = new Vector3d();
foreach (int plateIndex in node.PlateIndices)
{
extraNormal += this.Plates[plateIndex].Normal;
}
foreach (int plateIndex in node.PlateIndices)
{
if (Vector3d.VectorAngle(-extraNormal, this.Plates[plateIndex].Normal) < Math.PI / 4)
{
isSharp = false;
}
}
// If struts form a sharp corner, add an extra plate for a better convex hull shape
if (isSharp)
{
// Plane offset from node slightly
Plane plane = new Plane(node.Point3d - extraNormal * node.AvgRadius / node.PlateIndices.Count, -extraNormal);
// Compute the vertices
List <Point3d> Vtc = MeshTools.CreateKnuckle(plane, sides, node.AvgRadius, 0);
// Add new plate and its vertices
this.Plates.Add(new ExoPlate(nodeIndex, -extraNormal));
int newPlateIndx = this.Plates.Count - 1;
this.Plates[newPlateIndx].Vtc.AddRange(Vtc);
node.PlateIndices.Add(newPlateIndx);
}
}
/// <summary>
/// Generates sleeve mesh for the struts. The plate offsets should be set before you use this method.
/// </summary>
/// <param name="strutIndex">Index of the strut being thickened.</param>
/// <param name="sides">Number of sides for the strut mesh.</param>
/// <param name="sleeveMesh">The sleeve mesh</param>
public Mesh MakeSleeve(int strutIndex, int sides)
{
Mesh sleeveMesh = new Mesh();
ExoSleeve strut = this.Sleeves[strutIndex];
// Plate for the start/end of the sleeve
ExoPlate startPlate = this.Plates[strut.PlatePair.I];
ExoPlate endPlate = this.Plates[strut.PlatePair.J];
// Param at the start/end of the sleeve
double startParam, endParam;
startParam = startPlate.Offset;
endParam = 1 - endPlate.Offset;
// Set center point of start & end plates
startPlate.Vtc.Add(strut.Curve.PointAt(startParam));
endPlate.Vtc.Add(strut.Curve.PointAt(endParam));
// Compute the number of sleeve divisions (must be even)
double avgRadius = strut.AvgRadius;
double length = strut.Curve.GetLength(new Interval(startParam, endParam));
double divisions = Math.Max((Math.Round(length * 0.5 / avgRadius) * 2), 2);
// Generate sleeve vertices
Vector3d normal = strut.Curve.TangentAtStart;
// Loops along strut
for (int j = 0; j <= divisions; j++)
{
Plane plane;
// For linear struts
if (strut.Curve.IsLinear())
{
Point3d knucklePt = startPlate.Vtc[0] + (normal * (length * j / divisions));
plane = new Plane(knucklePt, normal);
}
// For curved struts, we compute a new perpendicular frame at every iteration
else
{
double locParameter = startParam + (j / divisions) * (endParam - startParam);
Point3d knucklePt = strut.Curve.PointAt(locParameter);
strut.Curve.PerpendicularFrameAt(locParameter, out plane);
}
// Compute varriable radius
double R = strut.StartRadius - j * (strut.StartRadius - strut.EndRadius) / (double)divisions;
// This angle twists the plate points along the strut, for triangulation
double startAngle = j * Math.PI / sides;
// Compute the vertices
List <Point3d> Vtc = MeshTools.CreateKnuckle(plane, sides, R, startAngle);
// If the vertices are hull points (plates that connect sleeves to node hulls), save them
if (j == 0)
{
startPlate.Vtc.AddRange(Vtc);
}
if (j == divisions)
{
endPlate.Vtc.AddRange(Vtc);
}
sleeveMesh.Vertices.AddVertices(Vtc); // save vertices to sleeve mesh
}
// Generate sleeve mesh (stitch vertices)
int V1, V2, V3, V4;
for (int j = 0; j < divisions; j++)
{
for (int i = 0; i < sides; i++)
{
V1 = (j * sides) + i;
V2 = (j * sides) + i + sides;
V3 = (j * sides) + sides + (i + 1) % (sides);
V4 = (j * sides) + (i + 1) % (sides);
sleeveMesh.Faces.AddFace(V1, V2, V4);
sleeveMesh.Faces.AddFace(V2, V3, V4);
}
}
return(sleeveMesh);
}
