Mtext within the AutoCAD-based products typically has a bounding box that forces text to wrap to another line when the text line length reaches the edge of the bounding box. While this is very commonly the desired effect, there are times when you desire a line of text to remain on a single line and you do not want to keep resizing the Mtext bounding box to accommodate the length of the text line.
Usage:
- Initiate the MTEXT command
- At the Specify first corner: prompt, pick a point which will be the justification point of the text.
- At the Specify opposite corner or [Height/Justify/Line spacing/Rotation/Style/Width]: prompt, type W for the Width option.
- At the Specify width: prompt, type 0 (zero).
- When the Mtext editor appears, proceed to type the desired text.
- Each time the ENTER key is pressed, a new line will be added to the text.
- No additional lines of text will be created unless the ENTER key is pressed.
Illustration:
The following illustration shows 2 Mtext objects and the differences between them.
Applying Technology to Architecture 
Thanks you. AutoCAD Architecture tips are always welcome.