Cutout Subdesign can be used to filter nets and/or clip a design by a polygon. To process the operation in the active design, select Use Current. To create a new design, select Create new and select whether the result should be created as a sub-design.
- If a polygon is selected before the operation is performed, it becomes the default extent polygon.
- If the selection is to be entirely by net, then no geometry should be selected before invoking the operation. If multiple polygons are selected, the union of these polygons forms the extent.
- If no data is selected, a new design is created with a stackup identical to the source design, but no geometry is transferred. Note, however, that filter geometry by net must also be selected.
- Cutout Subdesign works on hierarchy and footprints, however, everything is flattened into the sub-design that is created.
Select Layout >Cutout Subdesign to open the cut out window:
- Destination parent design — select "Use Current" to process the cutout in the active design, or choose an existing top-level design on the drop-down menu, or use "Create new parent Circuit Design" or "Create new parent EM Design". Only top-level designs with a stackup that matches the source design appear in the drop-down menu. If a new design is created, it takes its name on the original source design.
- Create the cutout as a sub-design in the parent — when selected, data is copied to a new sub-design within the parent; otherwise, the extracted data is inserted into the top-level design.
- Filter geometry by net — when selected, the net data is used to control the data selection and clipping; otherwise, the data in the net table is completely ignored.
- Nets:
- Net — the name of the net.
- <no net fill> — refers to polygon data without a net association.
- <no net trace> — refers to trace geometry (wide-line or plugin) without a net association.
- Include — when selected, the net is included in the data transferred.
- Clip at extents — when selected, the net is clipped against the extent polygon.
- Net — the name of the net.
- Net name filter — limits the data displayed in the net table. Use the filter to build up a selection of nets. The filter has no affect on the final outcome of the operation (e.g., if "Y" is entered, only those nets beginning with the letter "Y" are displayed; if "C*0" is entered, then all nets matching the wild-carded pattern are displayed). Nets that are not visible retain their "include" and "clip" settings.
- Extent polygon — name of the extent polygon.
- Reset — resets the extent polygon back to the original polygon; if there was no original polygon, then reset clears the auto-generated polygon.
- Create a sub-design for the included region — only applicable if you are creating a sub-design in the top-level design and after an extent polygon has been defined. This option represents the typical use of the Cutout Subdesign tool. The sub-design inserted into the top-level design consists of the data contained in the extent polygon (and filtered by the net selection). All geometry in the nets that is designated as "clipped" are truncated at the boundary of the extent polygon.
- Create a sub-design for the excluded region — same as the previous option, however, the sub-design contains the data outside of the extent polygon, filtered by the net selection and clipped as appropriate. It is possible to select both options; in which case two sub-designs are created: one of data in the extent and the other of data outside of the extent.
- Auto Generate Extent — displays a second
window that permits one to create an extent polygon derived either from
the non-clipped nets selected or the current extent polygon. The auto-generated
polygon is displayed in the Layout (though it may be difficult to see).
It is possible to execute this option as many times as one wishes, adjusting
the parameters as needed.
- Data source — the auto-generated extent can use either the current polygon selection or the non-clipped nets as the basis for generating a new extent polygon.
- Expansion Type — the derived region can be defined as a bounding box, a conformal polygon, or a convex hull of the selected data source.
- Expansion — the auto-generated extent polygon is an expansion of the selected data source; the expansion is either a factor (unitless fraction) of the overall source polygon extent or an absolute offset (e.g., 1mm, 20um).
- Cornerstyle — the type of corner to insert in the expanded polygon. Where a "corner" (the simple intersection of the offset edges) can result in rather poor results if there are acute or near-acute angles in the source polygon.
- Expansionincrements — at times, a single, large offset can generate a poorly formed polygon (a preview of the resulting polygon can be observed in the Layout window). The suitability of a polygon is entirely subjective. Improve the general quality of a polygon by breaking up the expansion into a series of steps (increments of 2, 3, 4, etc.). Such increments represent the number of iterations used to reach the full expansion distance. To improve the general quality of a polygon, the number of increments need not be large; you can start with a small number and increase them as appropriate. However, it is important to understand that increasing the number of iterations also increases the time to compute the expansion. So obviously, a very large number of iterations has a significant impact on computation time.