How to retrieve the cropBox's coordinates of a section view?

[maisoui]

Hi,

I'd like to retrieve the coordinates of a section view's cropBox.

(in red on the image below)

I have tried several things for a few hours, and I still have not found a solution. I read a lot of posts on this forums or on the Building Coder blog, but I run out of idea.

BoundingBoxXYZ box = view.cropBox;
Transform transform = box.Transform;

Does anyone have a solution?

[Anonymous]

The builtincategory is OST_Viewers and it has a boundingbox with a min and max value. Is that what you need ?

[maisoui]

I have the Min and Max box of the 3d box with view.cropBox, but my problem is how to compute the points of the polygon (rectangle) of this box in the 2d (section or elevation) view?

[Anonymous]

Than you need to project the coordinates to the 2d plane. Look here, maybe it helps:

http://thebuildingcoder.typepad.com/blog/2014/09/planes-projections-and-picking-points.html

http://thebuildingcoder.typepad.com/blog/2011/03/converting-between-2d-uv-and-3d-xyz-coordinates.htm...

[maisoui]

Thank you for your replay. I read all these posts and I guess I tried all the combinations of transformations/projections, but I'm not able to retrieve the correct coordinates of Min and Max points in plane view.

Does anyone have a code snippet or a suggestion?

[maisoui · Accepted solution]

Finally I found a solution. Maybe it could help somebody:

private IList<XYZ> computeBound(BoundingBoxXYZ box, Plane plane)
{
	double width = box.Max.X - box.Min.X;
	double height = box.Max.Y - box.Min.Y;

	IList<XYZ> points = new List<XYZ>();
	points.Add(box.Transform.OfPoint(box.Min));
	points.Add(points[points.Count - 1].Add(plane.XVec.Multiply(width)));
	points.Add(box.Transform.OfPoint(box.Max));
	points.Add(points[points.Count - 1].Subtract(plane.XVec.Multiply(width)));

	//project points on plane
	for(int i = 0; i < points.Count; ++i)
	{
		points[i] = plane.ProjectOnto(points[i]);
	}

	return points;
}

To project a point on a plane, read this : http://thebuildingcoder.typepad.com/blog/2014/09/planes-projections-and-picking-points.html

[desdinova]

Hi Jonathan

Could you share ProjectOnto Method ?

Thanks in advance...

[maisoui]

Here is the code from the link provided:

(Jeremy's blog: http://thebuildingcoder.typepad.com/blog/2014/09/planes-projections-and-picking-points.html)

/// <summary>
  /// Return signed distance from plane to a given point.
  /// </summary>
  public static double SignedDistanceTo(
    this Plane plane,
    XYZ p )
  {
    Debug.Assert(
      Util.IsEqual( plane.Normal.GetLength(), 1 ),
      "expected normalised plane normal" );
 
    XYZ v = p - plane.Origin;
 
    return plane.Normal.DotProduct( v );
  }

/// <summary>
  /// Project given 3D XYZ point onto plane.
  /// </summary>
  public static XYZ ProjectOnto(
    this Plane plane,
    XYZ p )
  {
    double d = plane.SignedDistanceTo( p );
 
    XYZ q = p + d * plane.Normal;
 
    Debug.Assert(
      Util.IsZero( plane.SignedDistanceTo( q ) ),
      "expected point on plane to have zero distance to plane" );
 
    return q;
  }

Regards

[miguelmachadoecosta]

---

@maisoui wrote:

Finally I found a solution. Maybe it could help somebody:

private IList<XYZ> computeBound(BoundingBoxXYZ box, Plane plane)
{
	double width = box.Max.X - box.Min.X;
	double height = box.Max.Y - box.Min.Y;

	IList<XYZ> points = new List<XYZ>();
	points.Add(box.Transform.OfPoint(box.Min));
	points.Add(points[points.Count - 1].Add(plane.XVec.Multiply(width)));
	points.Add(box.Transform.OfPoint(box.Max));
	points.Add(points[points.Count - 1].Subtract(plane.XVec.Multiply(width)));

	//project points on plane
	for(int i = 0; i < points.Count; ++i)
	{
		points[i] = plane.ProjectOnto(points[i]);
	}

	return points;
}

To project a point on a plane, read this : http://thebuildingcoder.typepad.com/blog/2014/09/planes-projections-and-picking-points.html

---

It helped me, but I had to do a few adjustments, depending on the view direction:

Public Const _eps As Double = 0.000000001
Private Function ComputeBound(box As BoundingBoxXYZ, plane As Plane, reverse As Boolean) As IList(Of XYZ)
    Dim width As Double = box.Max.X - box.Min.X
    Dim height As Double = box.Max.Y - box.Min.Y
    Dim points As IList(Of XYZ) = New List(Of XYZ)()
    points.Add(box.Transform.OfPoint(box.Min))
    Dim vector As XYZ
    If Math.Abs(plane.Normal.X) < _eps Then
        vector = New XYZ(width, 0, 0)
    Else
        vector = plane.XVec.Multiply(width)
    End If
    If reverse Then vector = vector.Multiply(-1)
    points.Add(points(points.Count - 1).Add(vector))
    points.Add(box.Transform.OfPoint(box.Max))
    points.Add(points(points.Count - 1).Subtract(vector))
    For i As Integer = 0 To points.Count - 1
        points(i) = plane.ProjectOnto(points(i))
    Next
    Return points
End Function

My criterion for reversing is:

Dim reverse As Boolean
If View.RightDirection.X < 0 Then reverse = True

[AmitMetzk]

With the help of Remy van den Bor comment and Revit Lookup
i noticed that the viewSection BoundingBoxXYZ is different from the crop Region BoundingBoxXYZ.

viewSection in revit lookup -> Snoop Active View -> BoundingBox

crop Region in revit lookup -> Select the crop Region -> Snoop Current Selection -> BoundingBox

we need the crop Region (which is OST_Viewers Category) in order to retrieve the cropBox's coordinates

here is the code i used to get it

//Retrieve Section view
ViewSection sec = doc.ActiveView as ViewSection;

//Retrieve Crop Region BoundingBox
ElementCategoryFilter filter = new ElementCategoryFilter(BuiltInCategory.OST_Viewers);
IList<ElementId> dependants = sec.GetDependentElements(filter);
ElementId viewrId = dependants.First();
Element viewer = doc.GetElement(viewrId);
BoundingBoxXYZ secBoundingBox = viewer.get_BoundingBox(sec);
			
XYZ topRight = secBoundingBox.Max;
XYZ bottomLeft = secBoundingBox.Min;

XYZ diagonal = topRight - bottomLeft;
XYZ rightDirection = sec.RightDirection;
XYZ upDirection = sec.UpDirection;
				
double width = diagonal.DotProduct(rightDirection);
double height = diagonal.DotProduct(upDirection);
				
XYZ bottomRight = bottomLeft + width*rightDirection;
XYZ topLeft = topRight - width*rightDirection;

[ntopo7]

Hi, this works for me, but not in all section views orientation

Im missing something?

    private IList<XYZ> computeBound1(BoundingBoxXYZ cropBox, Plane plane, Autodesk.Revit.DB.View view)
        {
            bool reverse = true;
   
            if(view.RightDirection.X < 0)
            {
                reverse = true;
            }
            else
            {
                reverse = false;
            }

            double _eps = 0.00000000;
            double width = (cropBox.Max.X - cropBox.Min.X);
            double height = (cropBox.Max.Y - cropBox.Min.Y);
            IList<XYZ> points = new List<XYZ>();
            points.Add(cropBox.Transform.OfPoint(cropBox.Min));
            XYZ vector = new XYZ();

            if (Math.Abs(plane.Normal.X) < _eps)
            {
                vector = new XYZ(width, 0, 0);
            }
            else
            {
                vector = plane.XVec.Multiply(width);
            }
       
            if(reverse)
            {  vector.Multiply(-1); }

           points.Add(points[points.Count - 1].Add(vector));
           points.Add(cropBox.Transform.OfPoint(cropBox.Max));
           points.Add(points[points.Count - 1].Subtract(vector));

           for (int i = 0; i < points.Count; ++i)
              {
              points[i] = plane.ProjectOnto(points[i]);
             }
           return points;

        }

Its works in some sections but i get this diagonal lines in other views:

any ideas?

Thanks