How do you set a custom viewport scale in AutoCAD?

You can set a custom scale for a layout viewport in AutoCAD primarily by using the Properties Inspector.

To set a custom scale using the Properties Inspector:

1. Select the viewport object in your layout.
2. Right-click on the selected viewport.
3. Choose Properties from the context menu. This opens the Properties Inspector palette.
4. In the Properties Inspector, locate the Scale section.
5. You will see options for both Standard Scale and Custom Scale. While Standard Scale lets you pick from a predefined list, the method for setting a custom scale is different.
6. To apply a custom scale, enter the desired scale value directly into the Custom Scale field in the Properties Inspector. This value represents the ratio of paper units to model units (e.g., 1:100, 1/4"=1'-0").

For example, to set a scale where 1 unit on the layout equals 50 units in model space, you would enter 1:50 or 1/50 in the Custom Scale field. AutoCAD will then adjust the viewport's zoom level to match this exact ratio.

This method provides granular control over the viewport scale, allowing you to use any specific ratio required for your drawing.