Personally I don't like to use the mirror command as there is usually a better way to achieve the desired result. I use mirror in sketches as that is really useful. I wouldn't say never use mirrored features but I would always look for a better way to achieve the geometry.
My tuppence anyway
One situation I've found that makes the mirror functionality useful is in symmetric models that have a lot of round and/or chamfer features. Putting all those features into the model makes it pathetically slow, even if they are all just holes in a flat plate. But making a model of a symmetric piece of the final part, putting the rounds/chamfers on it, then mirroring it to achieve the desired result is much faster.
That being said, I only mirror the model. I've suffered the consequences of mirroring individual features in the past, particularly the inability to modify features that have been mirrored, or to add new features to the mirror.
Its always been lacking, especially compared to NX.
I only tend to use it for basic geometry at the start of the model, or untill the geometry remains symmetric.
You can select the model name from the top of the feature tree and then mirror. This will then mirror all features before your mirror feature, you can also add newgeometry before the mirror which will be added
Im yet to find a way of adding features to a mirrored group, although you can add them to a patterns group????
Mirror in sketch is pretty good.
Mirror Part can be good for creating handed parts as it also copied associated drawings, but lacks the association for future modification. We therefor tend to side with family tables for this.
Personally I don't use it. Have seen too many issues downstream over the years. I primarily work in jigs and fixtures, but we have a few production parts that started out as mirrored and now are not! My biggest issue is usually with modifying mirrored weldment assemblies someone outside designed. I probably don't understand the functionally of the command as I usually manage to blow up the whole model then try to figure out how to fix it. I have enough trouble figuring out how I may have created something after a few years/software updates!
Some other thoughts on the subject of "Mirror"
Wondering if anyone has seen something like….mirrored features create dependencies that we should be aware of. The biggest issue comes in when trying to create drawings using "show dimensions".
The mirrored features are most likely not parametrically dimensioned like you would want to show on a drawing.
Based on “show dimensions” from mirrored features, when creating drawing, you would have to create dimensions will need to be used. (Not sure if that is a reason to not mirror on its own.)
Mirroring parts (not features) is another thing that is actually easy to accomplish for new mirrored components.
Developing mirror features during concepting and preliminary design (in my book would be acceptable); however, most likely I would re-creating the mirrored part as a standalone part when it is time to do the drawing.
For mirrored parts, I do not trust the system to reliably update the mirrored version.
I also have no love for external references.
For the most part, I avoid using save-as mirror for the above reasons.
I am also aware that if I manually create the mirrored part, I have to sustain both items.
That is perfectly consistent with most redline ECO procedures.
Exception I will note:
1) If the drawing includes the primary and a mirror companion on one drawing as a single part number, I may opt to use this functionality.
2) If the mirror part is formed at the time of assembly from a common flat part but mirrored, these become "altered" and is treated as such in Creo with file naming.
Using Creo 2.0
FYI, I have used PTC software for 20 years now.
I am seeking input from others with their opinions/issues/concerns with this command.
I've used it many times successfully.....while in part mode. I will NOT use it in Assy mode, especially with the "new" mirror command in creo 3 (not sure when it was introduced). I've certainly had SOME issues with it, especially if rounds and drafts are involved. Sometimes it works, but you need to reselect references for the rounds to work, sometimes it just bombs. Sometimes I use it to create mirror image parts within the same part (family table instance of left and right).
Yes, it SHOULD be more robust, and only mirror the geometry (without having to copy the surfaces), not the features if that's what you want, but I digress.............