Protrusion Mirroring Issue

jesse_thompson284

Hello Onshape Community!

I've been working on a design, but have had a hard time figuring out how to properly mirror a feature. Since the actual design has a bunch of extraneous parts and features, I worked up a separate document containing a minimum working example to demonstrate the issue. The document should be public already, and the share link is:

https://cad.onshape.com/documents/0f8e567d0d6f158c6fbb20b0/w/b33dd119eb06f6badfab5d68/e/be090b3ee30171e7b1958c58?renderMode=0&uiState=669c306ae847b4316fb0b020

I'm essentially trying to mirror a rectangular extrusion protruding from the side of a hollow box (which will later be made into a hinge or some other more complicated feature). I've found that if the height of the extrusion is less than the total height of the box's wall, I can use the Mirror tool (with either Feature Mirror or Face Mirror selected) and it will mirror as I would expect. This result is shown in the image below. Specifically, the smaller tab in the upper right part of the image is the original, and this was mirrored about the Front plane onto the back side.

However, if I try to do the same with the larger tab in the bottom right of the image, the software reports an error ("Mirror 2 did not generate properly: Failed to create pattern, check input.", see image below). After trying this with the as-extruded box (and tab), I noticed that the design didn't have a line separating the larger tab from the box (on the top and bottom faces). Thus, I thought that the shape of the tab 'feature' might not be closed. In an attempt to fix this, I used the Split tool (with Split Face selected) to split the top and bottom faces into two parts (one for the box and another for the tab). However, this doesn't seem to have solved the issue, as I still can't mirror the larger tab.

One more note: I attempted to use the "Part Mirror" option in the Mirror tool. This worked to create a mirror of the larger tab. However, it also filled in the rectangular depression in the lower left corner of the inside of the box. Unfortunately, my actual design isn't perfectly symmetric, as it has a similar depression.

Thank you in advance for your time. Also, this is my first time posting, so please let me know if there is a problem with the URL or if any additional details would be helpful.

robert_scott_jr_

Hello Jesse. I think the only reason the features mirror didn't work is because the reapply features box wasn't checked. I think that is needed when an action (e.g.mirror) is being performed on more than a single instance(e.g.extrude). - Scotty

Link

robert_scott_jr_

Hello Jesse. I think the only reason the features mirror didn't work is because the reapply features box wasn't checked. I think that is needed when an action (e.g.mirror) is being performed on more than a single instance(e.g.extrude). - Scotty

Link

nick_papageorge073

When originally extruding the tabs, make them as "new" not "add". Then mirror them as "part". You can optionally merge them to the main solid within the mirror tool using "add", or merge them afterwards with a union.

Example:
https://cad.onshape.com/documents/b983fc34b69e5d46edfc444e/v/247dbf6f5c8a96f36cfd357b/e/e86a8babdfe0930bbed39fb5

Since this "tab" is just a simplification of a more complicated shape, such as a hinge, finishing it completely as a separate part and then mirroring the final hinge will save a lot of time compared to mirroring it early and then doing the hinge details on both sides.

Also check out the shell command. Your overall approach to this box is a lot more complicated than it needs to be.

jesse_thompson284

Hello Scotty. Thank you for the reply! I feel a little silly that the answer was staring me in the face, but glad it was something so simple. In any case, checking the Reapply Features tick box solved the issue. I also appreciate that you took the time to rename the features in the timeline (I had forgotten that this could be done, since I only use Onshape sporadically). Cheers! - Jesse