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Axis through center of a curve?


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Am I being dumb? I have an imported model (Molex connector, native ProE) that has Curve features which are circles that represent the holes in the PCB for installation. It seems that should define location of a axis just as well as a cylinder but I don't see any way to get ProE to accept this.

Bernie Hayden



New member
make use edge of circle and create a datum curve and then divide the curve by creating points using length ratio at required places . then create axis through points



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Bernie XKL LLC,


1) Datum-point At Center of arc/circle.

2) Datum-plane Through the arc/circle - if you're not on Misfire skip this step and make datum at the next step.

3) Datum-axis Pnt Nml Pn.

No you're not being dumb.

In cases like this, the make datum or datum-on-the-fly is really useful - a datum-point-on-the-fly option would have been useful here too.

Seems to me PTC should be considering further development of the concept to other datum features and not eliminating them altogether as what has happened with Wild Foul.


A UDF using dougr's method is a very handy UDF to have around. .. especially when dealing with imported geometry or shrinkwrap models that may have holes, but no usable axis or inside cylindrical surface to grab.

The entire UDF should require oa single arc (edge or curve) in order to be placed (probably about about 8-9 mouse picks including Feature/Create/User Defined). A lot shorter if you create a mapkey.

If you use a regular (asyncronous) datum plane instead of a Make-Datum, I recommend redefining it to fit the arc. This way, if you unhide, or unblank it, it will show up only near the arc which is a lot more intuitive for downstream users.

-Brian Adkins


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