Questions similar to this appear on the Bentley Discussion Groups. These appeared in the VBA discussion group.

Q

• How can I rotate a text or text node element using VBA?

A  The Text Rotator VBA project answers those questions.

Text Rotator

TextRotator is a freeware utility for MicroStation CONNECT and earlier versions of MicroStation.

TextRotator lets you pick DGN text elements (VBA TextElement or TextNodeElement). Depending on the rotation method you choose, the text is rotated by the active angle, a user-supplied angle, reset to zero rotation, or rotated to match the view containing the cursor.

Text Rotator Form

The text rotator form (VBA UserForm) provides a simple user interface. Its option buttons let the user choose the rotation method. The Rotate button is a command that starts a text locator primitive class (clsTextLocator).

Text Rotator Class

The clsTextLocator implements the ILocateCommandEvents interface. You will find that interface documented in VBA help, along with examples. When the user picks a text element, that element is rotated by the chosen angle.

Degrees or Radians

Humans, like you, me and even computer programmers, think of degrees when we measure angles. However, geometric calculations are usually done using angles expressed in radians. Radians are more mathematically convenient than degrees.

Views and Rotation

When rotating an element, we need to calculate the rotation to apply. Rotation is specified by a matrix (VBA Matrix3d). We must calculate your required rotation in degrees to radians, then convert radians to a Matrix3d …

Dim rotation As Matrix3d
rotation = Matrix3dFromVectorAndRotationAngle(viewAxis, radians)

"What's viewAxis?" I hear you ask. With a 2D DGN model, that's easy: the view axis is the Z axis. With a 3D DGN model, it's more complicated because you can rotate a view to any orientation. We need to find that orientation in order to figure out the view axis.

Fortunately, a MicroStation View has a view plane. Think of the plane as an invisible sheet parallel to your computer's screen. A plane is identified by its normal, which is simple to find …

Public Function GetViewAxis(ByVal oView As View) As Point3d
    Dim plane As Plane3d
    plane = oView.ExtractFrontClippingPlane
    GetViewAxis = plane.Normal
End Function

Examine the code in the Text Rotator project to see how we perform 2D and 3D rotation.

More About Matrices

Examine the code in the Text Rotator project to see how we perform 2D and 3D rotation. You can read more about matrices, transforms and VBA.

Download VBA Text Rotator Project

The above code is available in this MicroStation VBA project. Unpack the ZIP archive and copy TextRotator.mvba to a location where MicroStation can find it. A good place to copy it would be ..\Organization\Standards\macros. To start rotating text, enter the following into MicroStation's keyin dialog …

vba run [TextRotator]modMain.Main

Questions

Post questions about MicroStation programming to the MicroStation Programming Forum.