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When placing ground vias to connect to my components Altium sometimes removes the via after connecting it with a trace to the pad.

In the following image, if I was to complete this trace. Altium removes my via and leaves the trace there...

enter image description here

(This is a fairly simple design with only two layers. The bottom layer functions as a GND polygon.)

I do not know if this is a known function of Altium, or if I am missing something.

edit: Altium does not always delete my vias. (I cannot find a pattern in the times that it does happens though.)

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    \$\begingroup\$ Hmm, you could check if the "remove loops" option is activated in the GND net properties, it may cause something like that. (Double click net in the PCB panel to open net properties). \$\endgroup\$ – Rev May 30 '16 at 8:47
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Dialog

This probably happens because you have turned "Automatically remove loops" on for the GND net so whenever Altium detects that your two GND points are already connected otherwise, it will remove one of the connections to remove a loop (which admittedly doesn't make much sense for the Ground net). While placing a GND track, press TAB, make sure the mentioned option (it's somewhere in the list to the right) is deselected.

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    \$\begingroup\$ As an addition as stated in my original comment: Check that the default "remove loops"-setting for the GND net is disabled in the net properties. \$\endgroup\$ – Rev May 30 '16 at 9:16
  • \$\begingroup\$ Thankyou, This solved my problem! I still do not understand why Altium would implement this option. Even more so set it as standard... \$\endgroup\$ – Jordakoes May 30 '16 at 10:07
  • \$\begingroup\$ For most nets loops are unwanted, cleaning them up automatically makes interactive re-routing quicker. gnd and power nets are an exception. \$\endgroup\$ – Peter Green May 30 '16 at 11:10
  • \$\begingroup\$ @PeterGreen ya. I don't know why one of Altiums most used feature (at least for me) is also the most painful when it automatically removes grounds. I'm re-grounding my board right now. :( \$\endgroup\$ – efox29 May 30 '16 at 13:40
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I do not know about Altium but my CAD package (PADS) has a special via type called a stitching via that are inserted in a special way. To insert them the parent net is selected globally and then the "Add Via" command is invoked to add the vias to the net. The stitching vias do not get auto optimized out like regular vias.

So check your Altium to see if there is a similar capabilty.

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