/// <summary>
/// Create the Polygonal Faces for a new Tessellated Solid by extruding the given loop along the given normal.
/// </summary>
/// <param name="loops"></param>
/// <param name="extrudeDirection"></param>
/// <param name="extrusionHeight"></param>
/// <param name="midPlane"></param>
/// <returns></returns>
public static List <PolygonalFace> ExtrusionFacesFrom3DLoops(this IEnumerable <IEnumerable <Vector3> > loops, Vector3 extrudeDirection,
double extrusionHeight, bool midPlane = false)
{
// for consistency with adding the extrusionHeight to the base plane, negate if it comes in negative
if (extrusionHeight < 0)
{
extrusionHeight = -extrusionHeight;
extrudeDirection = -1 * extrudeDirection;
}
// find transform to the XY plane and store the backTransform (the transform back to the original)
var transform = MiscFunctions.TransformToXYPlane(extrudeDirection, out var backTransform);
// make paths, the 2D polygons represening the 3D loops
var paths = loops.Select(loop => loop.ProjectTo2DCoordinates(transform, 0, true));
// the basePlaneDistance defines the plane closer to the origin. we can get this from the any input coordinate
var basePlaneDistance = extrudeDirection.Dot(loops.First().First());
if (midPlane)
{
basePlaneDistance -= extrusionHeight / 2.0;
}
var polygons = paths.CreateShallowPolygonTrees(false);
return(polygons.SelectMany(polygon => Extrude.ExtrusionFacesFrom2DPolygons(polygon,
extrudeDirection, basePlaneDistance, extrusionHeight)).ToList());
}
/// <summary>
/// Create the triangular faces of an extruded solid from 2D paths.
/// </summary>
/// <param name="paths">The paths.</param>
/// <param name="basePlaneNormal">The base plane normal.</param>
/// <param name="basePlaneDistance">The base plane distance.</param>
/// <param name="extrusionHeight">Height of the extrusion.</param>
/// <returns>List<PolygonalFace>.</returns>
public static List <PolygonalFace> ExtrusionFacesFrom2DPolygons(this IEnumerable <IEnumerable <Vector2> > paths, Vector3 basePlaneNormal,
double basePlaneDistance, double extrusionHeight)
{
var polygons = paths.CreateShallowPolygonTrees(false);
return(polygons.SelectMany(polygon => Extrude.ExtrusionFacesFrom2DPolygons(polygon,
basePlaneNormal, basePlaneDistance, extrusionHeight)).ToList());
}
/// <summary>
/// Sets the Solid Representation of the bounding box
/// </summary>
public void SetSolidRepresentation()
{
if (CornerVertices == null || !CornerVertices.Any())
{
SetCornerVertices();
}
SolidRepresentation = Extrude.FromLoops(new List <List <Vertex> >()
{
CornerVertices.Take(4).ToList()
}, Directions[2], Dimensions[2]);
}
//public void SetVolume()
//{
// Volume = 0.0;
// for (var i = 0; i < NumLayers - 1; i++) //Include the last index, since we already modified start or stop
// {
// if (Layer2D[i] == null || !Layer2D[i].Any() || Layer2D[i + 1] == null || !Layer2D[i + 1].Any()) continue;
// var halfThickness = 0.5 * (StepDistances[i + 1] - StepDistances[i]);
// Volume += halfThickness * (Layer2D[i].Sum(p => p.Area) + Layer2D[i].Sum(p => p.Area));
// }
//}
/// <summary>
/// Layer2D and 3D can be indexed in the forward or reverse order from the step distances.
/// This can be useful when working in a bi-directional scope. In both cases, it will start
/// by extruding the first valid loop in Layer3D and stop before extruding the last one (the
/// n-1 extrusion will have ended on at the distance of the final cross section).
/// If reversed, it will simply extrude backward instead of forward.
/// </summary>
public IReadOnlyCollection <PolygonalFace> ConvertToTessellatedExtrusions(bool extrudeBack = true)
{
if (!Layer3D.Any())
{
SetAllVertices();
}
var start = Layer3D.Where(p => p.Value.Any()).FirstOrDefault().Key;
var stop = Layer3D.Where(p => p.Value.Any()).LastOrDefault().Key;
var reverse = start < stop ? 1 : -1;
var direction = reverse == 1 ? Direction : Direction.multiply(-1);
var faces = new List <PolygonalFace>();
//If extruding back, then we skip the first loop, and extrude backward from the remaining loops.
//Otherwise, extrude the first loop and all other loops forward, except the last loop.
//Which of these extrusion options you choose depends on how the cross sections were defined.
//But both methods, only result in material between the cross sections.
if (extrudeBack)
{
direction = direction.multiply(-1);
start += reverse;
}
else
{
stop -= reverse;
}
for (var i = start; i *reverse <= stop *reverse; i += reverse) //Include the last index, since we already modified start or stop
{
if (!Layer3D[i].Any())
{
continue; //THere can be gaps in layer3D if this actually represents more than one solid body
}
double distance;
if (extrudeBack)
{
distance = Math.Abs(StepDistances[i] - StepDistances[i - reverse]); //current - prior (reverse extrusion)
}
else
{
distance = Math.Abs(StepDistances[i + reverse] - StepDistances[i]); //next - current (forward extrusion)
}
var layerfaces = Extrude.ReturnFacesFromLoops(Layer3D[i], direction, distance, false);
if (layerfaces == null)
{
continue;
}
faces.AddRange(layerfaces);
}
return(faces);
}