Mirror around an axis defined by points

bert_fourie

Can I mirror a part around an axis defined by selecting two points - say two midpoints on other parts?

Narayan_K

@ bert_fourie , You can't mirror a part using two points or line.For mirror you need to select plane or face.
You can pattern the part using circular pattern option.In circular patter you can select any lines/edges as axis.or you can also select any circular edge/face of other cylindrical part as axis.

bert_fourie

Hi Narayan

I have converted from free form modelling software, and, while I am happy to have the parametric capability, I do find the available drawing and manipulation tools very restrictive compared to what I am used to - the options are so limited!

It would be great fro instance to:
Define a mirror axis by two points as mentioned in my question.
Be able measure the distance between two circular faces by simply clicking on them like you can do with two points.
Get x y z measurements plus direct distance between two entities when clicking on them.

I have many more suggestions that would speed up modelling a great deal.

bert_fourie

Another one is to mirror a part as a way of turning the part the opposite direction, without, adding, removing or creating a new part.

NeilCooke

@bert_fourie once you have selected two items to measure, expand the measure tool bottom right to get the results you are looking for. If you hover over each value it will show you graphically on screen what the measurement is. 

I have never heard of mirror around two points since mirror of 3D object requires a plane to ensure the location is exactly what you want. Mirror around an axis is surely subjective and random?

bert_fourie

Hi Neil. thanks for that - very helpful.

As to the mirror - the two points define an axis, just as selecting a line would - you then select a degree to rotate around the specified axis. The same goes for copying, in which case you need to specify two points plus a plane, but this plane could just be front view plane, rather than a plane on the drawing object itself.

I am more than willing to demonstrate in screen share if somebody from Onshape was interested

bert_fourie

Actually, if you select a view and were able to lock the view as "working view", you only need one point to effect a mirror copy...

NeilCooke

Hi @bert_fourie we are of course always open to new feature requests, but you should always consider the differences between free form modelling and parametric modelling (everything has to be locked down, unambiguous, editable, and repeatable so that your model rebuilds predictably). 

You can currently rotate around an axis and  transform/copy along a line using the transform feature but you will always create a new feature, so things like mirroring the part will create a new part but you can always remove the original using the delete part feature. 

Also to mirror a part using a locked down view would require a specific mirror command which would need to be able to record the view, which would need a plane for repeatability, so you would be no better off for speed or ease of creation. 

Hope this helps. Not trying to dodge the issue just explain the reasons!

traveler_hauptman

NeilCooke said:

I have never heard of mirror around two points since mirror of 3D object requires a plane to ensure the location is exactly what you want. Mirror around an axis is surely subjective and random?

I'm not sure of the OP's intent, but for me this is not ambiguous. The definition is declarative. Each point is a mirror of the other; the mirror plane is perpendicular to the line between them and at the midpoint between them.

In plain language, "Mirror the parts in the same way that these points are mirrored."

NeilCooke

@traveler_hauptman your scenario is declarative, but I think the OP's request was to mirror about a line between the two points as you would in sketch (I could be wrong though!)

bert_fourie

Say I have a model that is symmetrical. Now I want to mirror a part which I crated on one side of the assembly to the other side. I am in say, "front" view. All I need to fully define the mirror is to specify that the current plane applies to the mirror, and click on the center of any symmetrical line on the model. Then execute the mirror.

I do take your point that I come from free form modelling and have to still develop a parametric mindset, so I will not pester you  

traveler_hauptman

@bert_fourie Is specifying the current plane needed? Seems like the symmetrical line has all the info about the symmetry you want to duplicate...

bert_fourie

If you mirror around a single point then specifying a construction plane is necessary. I not Onshape does not snap to the center of a line except when in sketching mode, if it did one could then specify a mirror plane by selecting three midpoints all on the center of the symmetric assembly in question. Maybe that is something Onshape could add?

scott_hess

Apologies for lateness, but I arrived here because I wanted to mirror some features at a certain angle around an axis.  My solution was to use "Circular Pattern", with 2 units (original and the copy) and the appropriate degree setting.