topic Programmatically Rotating a Block with attributes in .NET Forum

Programmatically Rotating a Block with attributes

Anonymous — Tue, 24 Feb 2015 17:49:09 GMT

am trying to programmatically rotate a block in AutoCAD. The block is a label which is composed of two parts, a frame and a text attribute inside the frame. I run the following method to rotate the block

public static BlockReference rotateBlockWithAttributes(BlockReference blockToRotate, Angle rotationAmount)
        {
            Transaction tr = db.TransactionManager.StartTransaction();
            DocumentLock docLock = doc.LockDocument();            using(tr)            using (docLock)
            {                blockToRotate.Rotation += rotationAmount.Radians;
                Autodesk.AutoCAD.DatabaseServices.AttributeCollection attCol = blockToRotate.AttributeCollection;
                foreach (ObjectId attId in attCol)
                {
                    AttributeReference attRef = (AttributeReference)tr.GetObject(attId, OpenMode.ForWrite);                    attRef.Rotation += rotationAmount.Radians;attRef.Position.TransformBy(blockToRotate.BlockTransform);
                }                tr.Commit();
                return blockToRotate;
            }
        }

The result of this code is pictured below. It is rotating the label in place instead of moving it with the block itself. I need the rotation to behave as if I just rotated the whole thing as one entity.

Re: Programmatically Rotating a Block with attributes

Anonymous — Wed, 25 Feb 2015 11:39:11 GMT

Hi,

Transform the block attribute tag position and then apply it to the attribute tag reference.

dim pos as Point3d

'read the attribute definition - attDef

pos = attDef.Position

'transform it and apply to the block attribute reference

attRef.Position = pos.TransformBy(blockToRotate.BlockTransform)

Regards,

gsktry

Re : Programmatically Rotating a Block with attributes

_gile — Wed, 25 Feb 2015 16:54:06 GMT

Hi,

In the code you posted, you start a Transaction but you neither Commit() nor Dispose() it...

Anyway, you can simply rotate the block reference using TransformBy() and the attributes will follow the rotation:

blockToRotate.TransformBy(
    Matrix3d.Rotation(
        rotationAmount.Radian, 
        blockToRotate.Normal, 
        blockToRotate.Position));

Re : Programmatically Rotating a Block with attributes

Anonymous — Thu, 26 Feb 2015 03:49:54 GMT

Thanks Gilles. It is very simple and worked well.