This post was driven by a request that I had on one of the presentations I did earlier this year at a user group meeting. I first saw this “trick” performed while watching the infamous Tips & Tricks Presentation that Phil Sluder does every year at SolidWorks World.
The SolidWorks Mid Surface tool is a tool that probably does not get used very often or probably more accurately has its really “specific” uses that are determined by each user. However, I believe the example below would have a more wide spread use by more users.
Below you will notice and extruded rod that will built off of the origin. The original sketch was created on the Front Plane but by not being on the origin it makes the other Planes unusable. Now, you could create new reference geometry to use but for what we are trying to accomplish, I think the Mid Surface tool might be a better fit.
1. Begin by going to Insert > Surface > Mid Surface
2. Select both end faces. Notice that when you select the 2nd face (as long as it is a valid selection), SolidWorks will automatically create a new Face Pair.
3. Now you will want to hide the original Solid Body that you had so that only the Surface Body is showing.
4. Now go to Insert > Surface > Extend
5. Select your newly created surface and type in what kind of end condition you would like to have. In the case of this, I am going to offset the surface by a Distance of .750in. This will insure that no matter what size my initial rod is changed to, my surface will ALWAYS be .750in bigger.
6. Now go to Insert > Boss / Base > Thicken
7. Again, select your surface, and thicken your surface by your desired amount.
In the picture below, I have highlighted the original dimensions from our model. The length was originally drawn at 10.000in and the diameter was originally drawn at 2.000in.
Now, if you would happen to change the length of your rod, you will notice that everything maintains its relationships and stays perfectly centered.
Or if you change the diameter, you will notice that the offsets maintain their relationships.
BUT, probably my favorite reason for using this tool is that you can even change the original sketch shape (in the case below, to a square) and it maintains ALL of your relationships and spacing.
Hopefully this post will trigger some ideas for you on how you can use this in a production environment. Feel free to share how you currently use the Mid Surface tool or how you might use it in the future. Also, feel free to drop a comment if you have any other questions about this tip.