An Underlay displayed in form•Z.

This is an image that can be imported and displayed on any active reference plane, useful for referencing or tracing. An underlay can be any of the available image formats (except Illustrator). These image files can be created in form•Z or by an external source such as another application or an image scanner.

The image shown in the Underlay box of the dialog appears mapped on the active reference plane immediately. By default, this is an image with the AutoDesSys logo.


To place a different underlay, in the Reference Plane Parameters palette, click on the Open icon (Cic_3778.ENU.png), found next to the Underlay box, to invoke the Underlay dialog. In it, click on the Load... button. This invokes the standard Open File dialog from where you can choose an image file. As soon as you click OK, the image appears in the Underlay dialog. As soon as you close this dialog (by clicking on its OK button) the image appears in the Reference Plane Parameters palette and on your active reference plane.


The underlay image remains visible as long as the reference plane remains active. If you make another plane active, the image will disappear, but you can assign an underlay image to that plane as well. In general, there can be as many underlays as reference planes, but only one is displayed (that of the active plane) at any given time.


At the lower portion of the Reference Plane Parameters palette, there are more options:


The Transparency sliding bar controls how transparent the underlay image may be. At the far left, the image is completely opaque. At the far right, it is invisible. Between the two ends different degrees of transparency can be set.


There are two methods for placing an underlay image: Fit To Plane Extents sizes the image to exactly fit the reference plane. Custom Placement allows you to enter specific placement and orientation parameters.


The X and Y values of Origin position the origin of the underlay image and the angle value in the Rotation field orients it. Then the exact size of the image may be set by one of two methods: By Scale allows you to define a scale for the image using one of three formats: inches, ratio, or scale percentage. These are correlated and changing one automatically updates the other two. By Dimensions allows you to set the size of the underlay image be explicitly entering its X and Y dimensions. Note that the two can be locked to be the same if a square shape is desired.


An Underlay dialog with a loaded image.


Image loaded image as an underlay in form•Z.


Underlays on custom planes


A custom plane created on the face of an object.


An underlay placed on the face of an
object with the Translucent option active.

In addition to the Cartesian reference planes (XY, YZ, and ZX), underlays can also be placed on any custom plane. Recall that these can be generated using the Define Reference Plane tool (Cic_4180.ENU.png) or the Edit Reference Plane tool (Cic_4181.ENU.png), both located at the lower end of the form•Z window. Also, recall that these are listed in the Custom Reference Planes palette, from where they can be activated. Once active, an underlay can be assigned to them as for the Cartesian planes. Note, however, that for custom planes generated from faces of objects, use of the Translucent option is advisable to make sure they are visible.


The Custom Reference Planes palette with its
context menu invoked.