ECAD Assemble Relative to Board vs. standard Assemble
When you bring a circuit board assembly into CREO via IDX, all of the components are brought in "Relative to Board". My understanding is that CREO understands that the components are being placed on either the top or bottom, and that they are physically located at some offset from a given edge or point on the board (typically the origin in the ECAD environment). I'm not an MCAD designer, (I run the ECAD department) and I'm wondering if there's a way that you could change the assembly method, so that you could utilize normal mates (to line componets up with the outside world) and then change it back to "Relative to Board" once the component is where you want it, before sending an incremntal placement file back to ECAD.
An example of this would be if you had some sort of enclosure with a hole in it for an LED to shine through. The ECAD team might create the board and place the LED close to the position that it should be in. Then, the CREO model gets updated through IDX, the MCAD team would then change the assembly method of the LED, so that they can mate the center of the LED to the center of the hole. Finally, the MCAD team would change the assembly method back to "relative to baord", and send an incremental file back to the ECAD team to import the final placement of the LED.