I have a section marker for which I would like to do a rotation around one of the endpoints of the line segment leader but I haven't been able to figure out how to get the coordinates of the endpoint. I'm able to get the bounding box of the overall section marker but not these specific coordinates. How can I do this?
Dear Skeletank,
I am checking with the development team for you... hang on...
Cheers,
Jeremy
Yes.
They say:
1. The section marker element is not exposed as a specific element type so I don’t think this position can be read at this time.
2. Regarding “Mirror Project”: I don’t have good ideas to add.
Sorry for not being of more help!
Cheers,
Jeremy
Beautiful sample!
Especially after the development team said 'no hope' 🙂
Thank you, and congratulations!
Definitive blog post material, if I may...
Cheers,
Jeremy
@jeremytammik : feel free to use my contributions for your blog
@Anonymous:
answer 1.
the boundingbox of a sectionline is the result of a number of elements
in the method I "hide" 2 and 3. You can't hide the cycle symbol, so the result is to large. I simply added the resulting line without the correction to the project and measured the surplus length. After checking that it is always the same, I implemented the constant _correction = 21.130014403 / 304.8
answer 2.
I didn't distinguish between section vs. callout markers, I merely presumed you had a section marker. There are 2 ways to test
if (_vType.FamilyName == "Section")
if (_viewFromSection.GetType()== typeof(ViewSection))
callouts are PlanViews or Elevations, as far as I know.
answer 3.
I don't know
answer 4.
i'm afraid that is truly hidden. The Section Head and Tail stay in the same position when flipping the section, but the viewDirection and RightDirection changes.
The most you can get is a line in the View.RightDirection
XYZ _direction = ToPlane2.Subtract(ToPlane1).Normalize();
return _direction.IsAlmostEqualTo(ViewBasisX) ? Line.CreateBound(endPoint0, endPoint1) : Line.CreateBound(endPoint1, endPoint0);
Cool solution, cool answers!
Preserved by The Building Coder for posterity here:
http://thebuildingcoder.typepad.com/blog/2017/03/ttt-to-obtain-section-marker-endpoint.html
Thank you!
Cheers,
Jeremy
Dear Daniel,
I asked the Gemini LLM for you, as described in my blog post, using the following prompt:
It spouts a confident and sensible-sounding answer, but I have no idea whether it is hallucinating or based on true facts.
I'll share it with you in case it contains any new hints or ideas that we were not aware of in the discussion above; you will be more capable than I at pointing out its faults, in case not:
Gemini: You're right, manipulating section view marker endpoints has historically been tricky. The "temporary transaction trick" described by The Building Coder in 2017 (and likely referencing Jeremy Tammik's work) was a clever workaround for limitations in the Revit API. While still functional, it's not the most elegant or performant approach. Thankfully, recent Revit API improvements offer a more direct and cleaner solution.
Let's break down the problem and the modern solution:
The Challenge:
Section view markers are represented by ViewSection elements. Their geometry, specifically the endpoint location, is tied to the view's crop region and internal Revit workings. Directly setting the endpoint coordinates can lead to unexpected behavior or exceptions because Revit manages the relationship between the section line and the generated section view.
The Modern Solution: CropBox Manipulation
The key is to understand that the section line's endpoint is directly related to the section view's CropBox. By modifying the CropBox, we indirectly control the section line's endpoint. This avoids the transactional complexities of the older approach.
Here's a breakdown of the process and a C# code example:
Get the ViewSection: Obtain the ViewSection element representing the section view marker you want to modify. You can do this by selecting it, iterating through views, or other methods depending on your add-in's context.
Access the CropBox: The ViewSection has a CropBox property. This is the crucial element we need to manipulate.
Modify the CropBox's Max or Min Point: The CropBox is defined by a BoundingBoxXYZ. The section line's endpoint corresponds to one of the corner points of this bounding box. You'll typically adjust the Max point in the direction of the section line.
Update the ViewSection: After modifying the CropBox, the ViewSection will automatically update, reflecting the changed endpoint. No explicit transaction is required for this specific operation.
using Autodesk.Revit.DB;
using Autodesk.Revit.UI;
using System;
namespace RevitAddin
{
[Transaction(TransactionMode.Manual)] // Or Automatic if appropriate for your context
public class ModifySectionEndpoint : IExternalCommand
{
public Result Execute(ExternalCommandData commandData, ref string message, ElementSet elements)
{
UIApplication uiapp = commandData.Application;
UIDocument uidoc = uiapp.ActiveUIDocument;
Document doc = uidoc.Document;
// 1. Get the ViewSection (assuming you have it selected)
ViewSection viewSection = null;
Selection selection = uidoc.Selection;
if (selection.GetElementIds().Count > 0)
{
Element element = doc.GetElement(selection.GetElementIds().First());
viewSection = element as ViewSection;
}
if (viewSection == null)
{
TaskDialog.TaskDialog.Show("Error", "Please select a section view.");
return Result.Failed;
}
// 2. Access the CropBox
CropBox cropBox = viewSection.CropBox;
// 3. Modify the Max point (adjust as needed for your section direction)
XYZ currentMax = cropBox.Max;
XYZ offset = new XYZ(1, 0, 0); // Example offset - adjust as needed
XYZ newMax = currentMax + offset;
cropBox.Max = newMax;
// 4. Update is automatic - no transaction needed for CropBox modification in this context.
uidoc.RefreshActiveView(); // Important: Refresh the view to see the change
return Result.Succeeded;
}
}
}
Key Improvements over the "Temporary Transaction Trick":
CropBox manipulation is much more straightforward than managing temporary transactions.Important Considerations:
CropBox point (Max or Min) and the appropriate coordinates (X, Y, or Z) based on the section view's direction.ViewSection or if other unexpected issues occur.uidoc.RefreshActiveView() is often crucial to immediately visualize the change in the Revit UI.By using this CropBox approach, you can efficiently and reliably manipulate section view marker endpoints in your Revit add-ins, leveraging the power of the modern Revit API. This method is significantly more efficient and easier to maintain than the older transactional workarounds.
What say you? True, false, ridiculous, helpful? Exploring the new technology and its limits... Thank you for checking and letting us know.
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