Allegro not placing parts at designated values!?

[Pack34]

I just noticed a strange bug. To comply with the mechanical spec I've been selecting the mounting holes with the movement tools and the specifying the location using the command "x 103.0 5.0" but when I double-check with the INFO tool it'll randomly be off by up to 0.2mm in any direction.

Is there a more precise way to place components?

[Alex Eisenhut]

Doubt there's a bug here. First, "x" is not a true Allegro command, it is an alias that is defined by default to be aliased to the "pick" command. So check that this alias is still the same, since it is easy to change it.
Second, I'm not sure what you mean by mounting holes, are you using a footprint or simply moving a via that you call a mounting hole?
Third, Allegro lets you move things by several different references, but the info will give the x-y origin.

For example, you can define a mounting hole symbol that contains a through hole pad. Simple. The symbol has a 0,0 origin, but you can place the pad anywhere you want inside the symbol, for whatever reason.

So... you can move this footprint by the symbol origin in the layout, but if you do "info" on the pin instead of the symbol, you'll get an offset.

Then of course, Allegro has etch and non-etch grids. Also, be careful in the setup. I've seen people converting mm to mils and playing with the accuracy and converting units a few times (playing around, I guess), and suddenly the whole database goes on a weird set of dimensions that can only be reset by refreshing all the symbols.

Check all that before submitting a Cadence bug report.

[Pack34]

It seemed to be more consistent when specifying more decimals. For example "x 5.000 5.000" as opposed to "x 5 5" produced much more consistent results. Maybe it was something odd because I'm working in mm instead of mils for board dimensioning, mounting holes, etc.

For mounting holes I'm using a specific part that's a simple through-hole pad.

[Neilm]

If you have snap to grid on it will snap to the nearest point - if where you want the holes is not exactly on the grid that would explain it.

[Alex Eisenhut]

No, Allegro snaps to grids when using the mouse, but pick at the command line overrides the snap.
That's why it's important to figure out if the alias is still the same, and if the units have been converted back and forth. Things go off when you play around with units and precision... refreshing all the footprints can solve that issue.