PCB_Cmd-GlossGloss_AD

Applied Parameters: None

Summary

Run this command to improve the quality of the selected routes by reducing the overall length and number of corners. The Gloss feature also supports differential pairs and will attempt to improve the amount of pair that is balanced in length and separation.

Access

The glossing tool can be accessed in the PCB Editor by:

• Choosing the Route » Gloss Selected command from the menus.
• Using the Ctrl+Alt+G keyboard shortcut.

Use

First, ensure that the routed track to which you want to apply glossing is selected in the design workspace before running the command. To select a routed net (or nets) for glossing:

• Select a segment anywhere within the route then press Tab to extend that selection to all connected tracks on that layer. A second press of Tab will extend the selection to all objects on that net on all used layers.
• Use Click+Drag a selection rectangle, from right to left, to invoke the select touching rectangle mode to quickly select a track segment in multiple nets then press the Tab key to select all connected tracks on that layer for all of the nets you have selected.
• To gloss only a section of a routed net, select a track segment at either end of the section. Alternatively, select a pin or a via to signify an end of the desired section. Then run the Gloss command. Only the routing between (and including) the selected segments (or specified pin/via) will be glossed.

After running the command, the tool essentially modifies the selected and routed track by:

• Keeping its ends in place.
• Using segments of regular directions (angles divisible by 45 degrees).

The modifications performed depend on what is selected for glossing:

• For single-ended (non-diff-pair) routes, modifications aim at reducing the route length. Also, the junctions of the route to adjacent primitives are kept "good" - no acute or right angles, with neat pad entries (although the pad entry design rules are not currently observed).
• When applied to differential pair nets, the tool recognizes "zipped" portions of the routes - where the pair is already at the defined diff pair gap from each other. Its goal is to "zip-up" the pair, reducing the lengths of any unzipped portions. The corresponding unzipped portions from opposite sides are made equal in length, if possible. Glossing is applied to each unzipped and zipped portion, trying to make it short and smooth but without sacrificing the parallel routing and length balance.
• For multiple routes/pairs, the tool attempts to straighten each of them after the obstructing ones have already been glossed. In some cases, however, this is not achieved, because the tool also tries to minimize the time spent. If an unglossed route is present after glossing a bundle of routes, run the glossing command again.

Notes

1. Lock any routes that you do not want glossed, as these are automatically excluded.
2. When applied to differential pair routes, the corresponding unzipped portions from opposite sides are made equal in lengths, if possible, but Gloss does NOT add meanders to the shorter side of the pair. If length balancing is not achieved naturally, the pair is left unbalanced.
3. Tracks at non-45 degree angle increments are not glossed unless they are almost regular.
4. Arcs are currently not glossed.
5. Gloss treats Subnet Jumper tracks as fixed.
6. Support for room-based rules:
   1. Gloss adheres to Clearance and Diff Pair Routing rules scoped to rooms.
   2. Gloss allows the route to change width as it it enters a room; it will attempt to preserve the original widths used both outside and within the room.
   3. If there is a width change at a room boundary, Gloss will leave the boundary-crossing at the existing location.
7. Gloss will attempt to apply the Preferred gap, where possible, when glossing a differential pair:
   1. If a diffpair was routed with the gap other than the Diff Pair Routing rule Preferred value, Gloss will attempt to change it to use the Preferred gap.
   2. It will, however, narrow it down as needed to ensure DRC-free passage in tight zones and balanced pad entries at the ends.
   3. This behavior is applied to the zipped portion of the pair (where the sides are at Max Gap or less from each other).
   4. Caveat: Gloss does not handle an unreasonably large Max Gap.
8. Repair dangerous pad entries:
   1. Gloss does not automatically comply with the SMT rules (SMD Entry & SMD To Corner) because they tend to encourage unnecessary jogs and circuitous routing.
   2. If the rules are present then it tries to recognize dangerous situations, such as the potential for solder bridging, and adjusts its behavior based on these rules.
   3. For this to occur, the Corner option must be disabled in SMD Entry rule, and the SMD To Corner rule must have a suitable setting.
   4. Rule deviations: Gloss will keep the track segment orthogonal with the pad edge being exited from, but will not necessarily keep it centered within that edge. Gloss will also allow the track segment to exit from the side of the pad, if the SMD to Corner distance and other applicable rules can be satisfied.