Get Elements In View see from Viewport in Sheet.

[Chuong.Ho]

Hi, I'm finding the solution able to just get elements can see from ViewPort and Sheet after user drag the view in sheet. I tried to look around but can't find any the solution can help to filter it.

You can see what I want  get is from white box of the image.

Anyone have done filters elements like this before ?

Any comment is appreciated !

This is function filter elements from viewid but it not correct in this case :

var collector = new FilteredElementCollector(doc, view.Id)
                .WhereElementIsNotElementType()
                .Where(x => x.Category != null && x.Category.HasMaterialQuantities)
                .Where(x => x.Category != null && x.Category.CategoryType != CategoryType.AnalyticalModel)
                .Where(x => x.Category != null && x.Category.CategoryType != CategoryType.Internal);
            List<Element> elements = collector.ToList().Where(x => x != null).ToList();

[jeremy_tammik]

I am not aware of a perfect solution for this. Here are some recent discussions and attempts:

• Visibility of a Specific Element in a View
• Determining Elements Present in Section View
• Two Ways to Determine Elements in Section View

[Moustafa_K]

I trust it is possible to filter elements visible in a viewport, but it requires some calculations. The process involves:

1. Getting the viewport outline – Retrieve the viewport's bounding box on the sheet.
2. Projecting to model space – Convert the outline points to model coordinates using the viewport’s transform.
3. Applying view range offsets – Adjust for top and bottom clipping to define a proper 3D selection box.
4. Creating a bounding filter – Use the computed 3D outline to filter elements inside the viewport.
5. Applying a tolerance buffer – This ensures elements exactly on the edges, like thick floors, are included.

I'm a bit confused about the OutLine class. Its constructor accepts minimum and maximum points, which makes it seem similar to of BoundingBoxXYZ class. I'm having trouble understanding the difference and why a BoundingBoxXYZIsInsideFitler requires an OutLine instead of a BoundingBoxXYZ. Even though the word "outline" typically, "at least for me" refers to a 2D shape, the OutLine class seems to be used in a 3D context here.

Here’s the final implementation:

public static XYZ ConvertToModelSpace(this XYZ pointOnSheet, Viewport viewPort)
{
    var Doc = viewPort.Document;
    var modelSpaceView = (View)Doc.GetElement(viewPort.ViewId);
    var viewTransform = modelSpaceView.CropBox.Transform;

    BoundingBoxUV modelSpaceOutline = modelSpaceView.Outline;
    var cgModelSpaceUV = (modelSpaceOutline.Min + modelSpaceOutline.Max) / 2;
    var cgModelSpace = new XYZ(cgModelSpaceUV.U, cgModelSpaceUV.V, 0);

    Outline vportOutLine = viewPort.GetBoxOutline();
    var cgVportOutline = (vportOutLine.MinimumPoint + vportOutLine.MaximumPoint) / 2;
    var offset = cgVportOutline.Subtract(cgModelSpace);

    int Scale = modelSpaceView.Scale;
    return viewTransform.OfPoint((pointOnSheet - offset) * Scale);
}

var outline = viewPort.GetBoxOutline();
var p0 = outline.MinimumPoint.ConvertToModelSpace(viewPort);
var p1 = outline.MaximumPoint.ConvertToModelSpace(viewPort);
var view = viewPort.ViewId.GetElement<View>() as ViewPlan;

var range = view.GetViewRange();
var maxZ = range.GetOffset(PlanViewPlane.TopClipPlane);
var minZ = range.GetOffset(PlanViewPlane.ViewDepthPlane);
double tolerance = 2;
p0 = new XYZ(p0.X, p0.Y, minZ - tolerance);
p1 = new XYZ(p1.X, p1.Y, maxZ + tolerance);

outline = new Outline(p0, p1);
var bbxFilter = new BoundingBoxIsInsideFilter(outline);
var elements = new FilteredElementCollector(Doc, view.Id)
    .WherePasses(bbxFilter)
    .WhereElementIsNotElementType()
    .Where(x => x.Category != null && x.Category.HasMaterialQuantities)
    .Where(x => x.Category != null && x.Category.CategoryType != CategoryType.Internal)
    .Where(x => x.Category != null && x.Category.CategoryType != CategoryType.AnalyticalModel);

List<ElementId> ids = elements.Select(o => o.Id).ToList();
UiDoc.Selection.SetElementIds(ids);

I have added more details of how this works in case any one likes the details. 

Hope this helps.

[Chuong.Ho]

Hi @Moustafa_K  and @jeremy_tammik , sorry for my busy work late reply, the code is really useful . Many thanks for the solution, I haven't have time to test the code shared but I belive is still can't resolve 100% in this case.

Regards .