SOLIDWORKS 2018 3D Sketch Mirror

For a long time, I’ve liked 3D Sketching, but I’ve always missed one important function: Mirror. I love using Mirror in a 2D Sketch, and the function is as old as SOLIDWORKS in a 2D Sketch. But how about a 3D Sketch Mirror? My friends, the long wait is over! SOLIDWORKS 2018 finally has 3D Sketch Mirror. Wondering what it is like? Let’s take this example:

Pesky edge on a cool spring

Anyone who has taken the SOLIDWORKS Advanced Part Modeling course will immediately recognize this spring. During the lesson, we used a Fit Spline to eliminate the tangent edges, but when we apply the mirror, we get an edge at the mirror plane due to the fact that the faces are not continuous. Avoiding this edge is a lot of extra work! Let’s see how we can do this differently in SOLIDWORKS 2018. I delete the mirror feature knowing that if I can do the whole thing as a Fit Spline then I can get rid of the aforementioned pesky edge.

Behold: the Fit Spline

I then choose the Fit Spline and the front plane, and run the Mirror command. This should create the 3D Sketch Mirror, but I’m greeted by an odd warning message:

SOLIDWORKS Warning Message

Now, if I only selected the fit spline and the plane, I get a mirrored fit spline which is undefined, but it is still a second sketch entity and will not eliminate the pesky edge.

Sketch is Under Defined

Since this does not address the issue of the pesky edge, I will need to reconsider what I am trying to do here. The end goal is for my to have a single Fit Spline for everything, so I decide to delete the Fit Spline, then select all the sketch entities I was using for my Fit Spline, pick my mirror plane, and run the 3D Sketch Mirror on those:

Mirror Steps

The mirrored reference entities come through without issue – no error message. I can then create a Fit Spline on all the entities and perform my sweep.

Mirror created