Sketch Mirror Error

[neljoshua]

I am having some issues with sketch mirror. Mirror will not work on the selected entities. Well, at least it will not mirror around a vertical line; mirror worked fine (with the same entities) around a horizontal line.

I would make a Screencast, but it does not seem to work with a 4k monitor. All I got was a black screen with my mouse moving around. But I digress.

It could be that I am doing something wrong, but I have no idea what it is. Any thoughts are appreciated.

Thanks!

[SBix26]

I don't understand it completely, but here's what I discovered:

• The arc is the only entity that won't mirror around the center construction line
• The arc fails to mirror only around that center line; it works just fine with every other vertical line in the sketch

No idea what it is about that arc and that line that causes the failure.

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Sam B
Inventor Pro 2020.1 | Windows 7 SP1
LinkedIn

[johnsonshiue]

Hi! I am sorry I am also confused. I cannot seem to reproduce the problem. Could you install 2020.1 update and see if it works better? You are on 2020 RTM build 168.

Many thanks!

[neljoshua]

@SBix26 & @johnsonshiue,

Thanks for your help. I am confused as well and was hoping for a way to explain this to my students.

I updated yesterday to 2020.1 and still have the same issue. I have not tried re-creating the file with 2020.1, but I may do that and see if the issue persists.

[Anonymous]

As mentioned recently in another post, and also my conclusion in seeing this sketch, there is no need to create mirrors in sketches to end up with symmetrical parts. You can perfectly create half of this part and mirror the final result. It's far more robust, uses leaner sketches and less variables.

And symmetrical parts should always be symmetrical about the main planes. Allows you to assemble parts with minimal dependencies to part features.

Attached one of the ways to create the part. Much depends on the use and the design intents. Discrete feature steps are far more dependable than extensive sketches.

Note : I've used the option to change construction lines into 'centerline' to be able to give the full dimension instead of half the dimension, it's easier to read and check. I take the Ø-sign as "collateral damage".

[neljoshua]

@Anonymous,

Agreed 100%.

The reason that I am doing this in the sketch is that this set of problems focuses on sketching tools. I brought this up here because it seems to be a bug.

[johnsonshiue]

Hi! I think I see the issue now. The error has something to do with creating overlapped geometry. There is already existing sketch geometry on the mirror side. The newly mirrored geometry will be on top of it. It is blocked.
Another workflow you might look into is Sketch Block. Right-click on the Sketch panel -> check Layout. Use "Create Sketch Block" command to convert sketch geometry into sketch blocks. The nice thing about this is that you don't need  to recreate sketch lines. You can insert the blocks repeatedly. The blocks act like rigid bodies. It reduces a lot of degree of freedom. You can also import AutoCAD blocks as sketch blocks.

Many thanks!

[david.ewing.ara]

that is one of the best suggestions I have heard. Thank you!