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Tip: Smooth Your Clines Without Breaking Phase Tuning

Gowtham P

When routing with Slide (Hug Preferred), clines often get broken into many small segments. Using Custom Smooth helps clean up these segments, but it can also modify geometry and potentially strips any tuning from the cline, which is a concern for high‑speed or phase‑critical nets.

A practical way to handle this is to apply glossing only to selected portions of the cline, while explicitly preserving the phase‑tuned region:

  1. Open Route > Gloss > Parameters to launch the Glossing Controller.
  2. Click Line Smoothing to open the Line Smoothing form.
  3. Set Number of executions = 1 and click OK.
  4. In the Glossing Controller, set only Line Smoothing to Run.
  5. Close the Glossing Controller.
  6. Go to Route > Gloss > Window and draw a window around only the cline segments to be smoothed, avoiding the phase‑tuned section. RMB > Done.
  7. Reopen Route > Gloss > Parameters and click Gloss to apply smoothing only within the selected window.

Now, when you run the Glossing tool, clines are glossed but the Phase Tuning remains.

Red are the windows drawn for Glossing and yellow is the area avoided by the tool.

How do you handle glossing on delay‑sensitive nets?
Do you prefer window‑based glossing, or do you rely to re‑tune after cleanup?

Parents
  • avant

    I don't gloss after tuning. 

    But if I did, I'd simply apply the "fixed" property to those clines.

    In the example shown, total cline length has changed after tuning.

  • Gowtham P
    in reply to avant

    Fair point - fixing the cline definitely keeps things safe.

    There are instances though where locking the whole net can limit cleanup a bit, especially after Slide (Hug Preferred) introduces a lot of small segments outside the tuned region. That’s where selective glossing can help clean up only the non‑critical sections while leaving the tuned area untouched.


    Do you normally just leave those small segments as‑is then, or clean them up earlier in your flow?

Reply
  • Gowtham P
    in reply to avant

    Fair point - fixing the cline definitely keeps things safe.

    There are instances though where locking the whole net can limit cleanup a bit, especially after Slide (Hug Preferred) introduces a lot of small segments outside the tuned region. That’s where selective glossing can help clean up only the non‑critical sections while leaving the tuned area untouched.


    Do you normally just leave those small segments as‑is then, or clean them up earlier in your flow?

Children
  • avant
    in reply to Gowtham P

    After trace routing is completed, I run gloss to minimize the length of those traces.

    I look at the longest and shortest traces and re-route if necessary. 

    I clean up traces as I tune. 

    Tuning length contraint includes the entire trace length. 

    Glossing a tuned trace, even outside of the "tuned" region can alter the total length, because glossing does not adhere to delay constraint values.

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