While IGES and STEP are the bees knees when it comes to pulling primitive features off a model, I'm noticing it is extremely difficult to do so on an STL polygonal model...
is there a best practice for this? Or is it just time consuming? (i.e. pick and place, best fit, etc.)
John,
I'm a little confused with exactly what you are trying to do.
Are you trying to export complex surfaces from you scanned polygonal model?
Sorry, that was really vague...
I figured it out anyway... I have, as a reference, a perfect STL model given to me by a customer. This is not my scanned data.
It's a little bit of a pain extracting the features (for GD&T) off a mess of triangles as opposed to having a nice IGES file.
8)
No other chance than doing it with the 'normal' fitting stuff.
In cases like you described I sometimes start to create all my nominal on the stl just by picking (e.g. a circle with three points), starting with the 'perfect' stl as data object. So I get all my nominal primitves in a fast - not accurate way, but can use the autoextraction to create measured ones. Now the trick: Delete all nominals, switch the measured to nominal primitives and put the previous data stl as reference. ;D
Here is one other method:
The fit method has a sub-method called "pick then fit".
For a plane, you pick three points (make a plane) and polyworks will look for points with the same normal (within max angle) and within a proximity of the picke plane extended infinitely.
The same method is available for all features. The search distance is by default 1mm around the picke feature.
If you have a perfect STL, it should work.