I'm new at using CAD models and am having trouble getting my measured features to line up with the CAD iges File I am importing. When I bring the CAD model in, it takes the origin of the CAD model to the origin of the Romer. When I measure the actual part, all my measurements are off in space in the initial alignment compared to the CAD model. After I do the first manual alignment, Plan/Line/Point, and level and rotate and origin what do I do next? I tried doing the CTRL+F4 and making a plane, line, and point on the part, then rehitting and aligning again. This just put my new features off to the side with the other. What am I doing wrong? Please help! lol.
The thread explains everything in great detail. Thanks, I wouldn't have found it. The only problem is, I don't have that F5 Part/Setup tab for aligning your CAD model to the machine. Would you know how to get that tab. Our DCC machines have it, but my Romer Arm doesn't. Thanks VinniUSMC!
Assuming that all your measured alignment features have correct theoretical values picked up from CAD and are 3D features (i.e. CAD clicked Auto features with Sample points), everything should click after the alignment.
If you use 'Measured features' you *must* enter correct THEOs by hand.
If you use 2D features depending on the workplane during alignment it will fail (there is no reliable workplane before your first alignment when using an arm).
So, you are saying that by using 2D features I probably won't get the CAD=PART alignment thing to work? Should I then use only 3D features to do my initial alignment? I appreciate your help here.
Yes, the Romer arm has no [known to PC-DMIS] relation to the surface your part is resting on, so the 'workplane' you have when starting up is in relation to the arm itself. 2D features are calculated parallell to (or even projected to) the WORKPLANE, and won't work in this case.
I figured it out. When I was trying to use CAD=Part I was assuming it was doing a best fit or something. The CAD model had a weird origin in it and it wasn't the same as I was trying to do with my alignment. I had to do an alignment first, then I created an offset XYZ point and set my origin there. After that I did another alignment with CAD=Part and everything snapped into place. I was so overthinking this! lol. Thanks everyone for the help!!
import model
create primary datum offline and LEVEL (ex: a plane)
create secondary datum offline and ROTATE (ex: a cylinder)
create tertiary datum offline. ORIGIN in X, Y, and Z (ex: a circle becomes X origin, cylinder becomes Y origin, plane becomes Z origin. of course, this depends on the drawing)
execute, forcing us to probe the features
you should be aligned. No CAD=Part is necessary.
As an aside, it sounds like you're trying to learn all this yourself? One cannot be trained from an online forum. Please go to Hexagon's PCDMIS Portable class, there are a ton of nuances (blueprint reading, alignment practice, probe calibration, probe choice, 2D line scans, feature construction, arm and probe checkouts) that a forum would take YEARS to give you, and you can get it in a mere week with the course.