topic Re: How to change UCS for model space inside viewport ? in .NET Forum

How to change UCS for model space inside viewport ?

nghiabt04 — Sun, 29 Jan 2023 09:11:11 GMT

Hi,

Currently, I want to change UCS of model space in viewport but don't know how to do.

I found the method

.SetUcs()

but it's not working.

Does anyone knows to do it, please advise me.

Thanks and Regards.

Re: How to change UCS for model space inside viewport ?

_gile — Sun, 29 Jan 2023 12:13:25 GMT

Hi,

The Viewport type has a Ucs read/write property.

Re: How to change UCS for model space inside viewport ?

nghiabt04 — Mon, 30 Jan 2023 08:30:05 GMT

Hi @_gile,
I also try this but see nothing change.

Re: How to change UCS for model space inside viewport ?

_gile — Mon, 30 Jan 2023 16:00:01 GMT

Hi,

Most often when dealing with viewport, we need to swich them off and on to update the changes.

Try this way:

vp.On = false; vp.Ucs = ucs; vp.On = true;

Re: How to change UCS for model space inside viewport ?

ivanstarr3 — Wed, 26 Feb 2025 12:29:21 GMT

I'm also having the same problem but in pure model space (tilemode=1). Also, after including the code in my project, the plugin made autocad run very slow. very strange. I will include the code below. Thanks in advance Mr. Chanteau, or whoever else helps! Also, how do I create that code window that you have your code example in above?

using System;
using Autodesk.AutoCAD.Runtime;
using Autodesk.AutoCAD.ApplicationServices;
using Autodesk.AutoCAD.DatabaseServices;
using Autodesk.AutoCAD.EditorInput;
using Autodesk.AutoCAD.Geometry;

namespace ArchitecturalWindows
{
public class UCSCommands
{
private static ObjectId previousUcsId = ObjectId.Null; // Store the previous UCS ObjectId
private static bool wasWorldUCS = true; // Track if the previous UCS was World UCS

public static void SetNewUCS()
{
Document doc = Autodesk.AutoCAD.ApplicationServices.Core.Application.DocumentManager.MdiActiveDocument;
Database db = doc.Database;
Editor ed = doc.Editor;

using (Transaction tr = db.TransactionManager.StartTransaction())
{
// Get the UCS table
UcsTable ucsTable = tr.GetObject(db.UcsTableId, OpenMode.ForRead) as UcsTable;

// Get the current viewport settings
ObjectId viewportId = db.CurrentViewportTableRecordId;
ViewportTableRecord vpRecord = tr.GetObject(viewportId, OpenMode.ForWrite) as ViewportTableRecord;
previousUcsId = vpRecord.UcsName;
// Store the current UCS
if (ucsTable.Has(vpRecord.UcsName))
{
previousUcsId = vpRecord.UcsName;
wasWorldUCS = false;
}
else
{
previousUcsId = ObjectId.Null;
wasWorldUCS = true;
}

// Define a new UCS
string ucsName = "MyNewUCS";
UcsTableRecord newUcs;

if (ucsTable.Has(ucsName))
{
newUcs = tr.GetObject(ucsTable[ucsName], OpenMode.ForRead) as UcsTableRecord;
}
else
{
ucsTable.UpgradeOpen();
newUcs = new UcsTableRecord
{
Name = ucsName,
Origin = new Point3d(10, 10, 0), // Example new origin
XAxis = new Vector3d(0, 0, 1),
YAxis = new Vector3d(0, 1, 0)
};
ucsTable.Add(newUcs);
tr.AddNewlyCreatedDBObject(newUcs, true);
}

// Set the new UCS to the viewport
vpRecord.SetUcs(newUcs.ObjectId);
vpRecord.UcsSavedWithViewport = true; // Mark UCS as saved with this viewport

tr.Commit();
ed.WriteMessage("\nNew UCS set as current.");
}
}

}

Re: How to change UCS for model space inside viewport ?

_gile — Wed, 26 Feb 2025 13:41:03 GMT

Hi,

The Database.CurrentViewportTableRecordId property is not reliable because it does not update correctly.

To set a new UCS in the current viewport, you can simply set the Editor.CurrentCoordinateSystem property.

public static void SetUCS(Point3d origin, Vector3d xAxis, Vector3d yAxis) { var zAxis = xAxis.CrossProduct(yAxis); Application.DocumentManager.MdiActiveDocument.Editor.CurrentUserCoordinateSystem = Matrix3d.AlignCoordinateSystem( Point3d.Origin, Vector3d.XAxis, Vector3d.YAxis, Vector3d.ZAxis, origin, xAxis.GetNormal(), yAxis.GetNormal(), zAxis.GetNormal()); }

@ivanstarr3 wrote:

Also, how do I create that code window that you have your code example in above?

1. Hit the "Expand toolbar" button:

2. Hit the "Insert/Edit code sample" button:

3. Choose the language and past the code:

Re: How to change UCS for model space inside viewport ?

ivanstarr3 — Wed, 26 Feb 2025 15:39:09 GMT

Wow thanks Mr. Chanteau! So fast a response!