Download Altium Project File
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Using three single pin components (A,B,C) with net name (DDR_D1).
PCB layout with grid set for 100 mil.
A to D = 400mil
B to D = 300mil
C to D = 200mil
A to B = 700mil
A to C = 600mil
B to C = 500mil
Total routed length on single layer = 900mil
Using the PCB Panel > Nets
The total routed Net length of 900 mils is shown correctly.
Using the PCB Panel > From- To Editor
The routed length from point A to B of 700 mils is shown correctly.
Let's make things a bit more interesting by adding a via at point 'D'.
Checking PCB Panel > Nets
The total routed length of 900 mils is shown, note the stub length of the via is not included.
Next move the routed segment 'B to D' to the bottom layer and delete the 'C to D' segment.
Using a simple 4 layer stack up (66 mil thick)
Checking PCB Panel > Nets > length of 764 mils is shown.
The via length was accounted for, this is a new feature in AD14, nice !
However as shown below the 'From -To Editor' does not account for via length.
Click on image to view
There is a 64 mil difference.
For high speed designs you may want to account for the via lengths.
The via length data is stale and is not updated as you edit the design. This can be observed by placing a track from 'B to D' on Mid-Layer 1 and a track on Mid-Layer 2 from 'C to D'.
Checking PCB Panel > Nets > routed Net Length of 943 mils is shown.
Next delete the 'C to D' track segment.
Checking PCB Panel > routed Net Length of 743 mils is shown. This length is not correct, the length should be 722 mils.
Now drag the track from 'A to D' then put it back and note the PCB panel updates to 722 mils.
Sticky dashed lines
To get rid of the sticky dashed line left behind by the 'From-To Editor' open the PCB Panel > Nets > Click anywhere in the PCB > Press the End key.
Net length Measurements
Menu > Reports > Measure Selected Objects.
This length 2.005 Inch does not include the selected vias in both AD14.2.5 and AD14.3.13
Compare AD14.2.5 and AD14.3.13
AD14.2.5 Headups Display length = 2005 mils (No VIA Length)
AD14.2.5 PCB Panel length = 2005 mils (Vias NOT Included)
AD14.3.13 Headups Display length = 2090 mils (Includes 2 VIAs)
AD14.3.13 PCB Panel 'Nets' length = 2090 mils (Includes 2 Vias)
AD14.3.13 PCB Panel 'From-To Editor' length = 2005 mils (Does Not Include Vias)
Differential Pairs
Differential pair lengths shown in the 'From To Editor' are also incorrect.
As shown below the measured length is 2212 (correct) and the 'From To Editor' length is 2170 (wrong - does not include VIAs).
Reports > 'Measure Selected Objects' = 2212 (correct)
Conclusion:
AD14.3.13 includes via lengths in the Head Up Display and PCB Panel 'Nets', but NOT in the 'From-To Editor'.
The Reports > 'Measure Selected Objects' does not include the selected vias in the measured length data.
These differences maybe significant for high-speed designs. Depending on the timing requirements of your design you may need to go to great lengths (pun) to ensure you have properly matched length nets.
See Bug Crunch #137 - Altium
See Bug Crunch #960 - Altium
See Bug Crunch #4601 - Altium
That's it.
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