Getting Rid of Excessive Clicking with the Radiate Knit Combo

Nowadays, most of the functionality within SOLIDWORKS is very well-known. It’s rare to come across functionality that’s powerful but rarely spoken about. However, I did come across a cool tool that tackles a bunch of problems, and out of everyone I’ve shown it to, none of them knew it was there.

The challenge is a fairly common one. I want to use a bunch of faces for some operation,such as a cut with a surface or to thicken a surface for a gasket, but I don’t want to repeatedly click all the faces. Who am I, Tom Seppola? According to a quick Googling, he holds the current world record for the number of clicks in 10 seconds.

More importantly, any selection of faces is only going to be good for that one design. That doesn’t seem very parametric or robust, does it? Plus, if anything changes, downstream features will fail from missing faces, and it’s back to repeatedly clicking.

Figure 1. The desired finished design.

For this scenario, let’s say I need to make a rubber gasket that lines a funky box as shown in Figure 1. I know this design is always going to have a certain face since it’s specially molded to fit inside and around a bunch of other components. We’ll use the face shown below in Figure 2, since that’s the mounting surface (YELLOW).

I also know there will be a large face (RED) that comes from a feature that’s not likely to disappear because it’s a main Loft feature—it will be there no matter how many fillets, chamfers or additional geometry changes are made.

Figure 2. Starting point.

How can a user select all the connecting faces shown below (ORANGE) every time for this gasket? The default solution most people use is Copy Surface and select all the faces. That’s painful and time consuming in itself, but what if there are going to be design changes? What if some of those orange faces change or disappear or other faces are added to the mix from new features?

Figure 3. All the faces to select.

There’s actually a slick trick to solve this type of challenge—without hunting and clicking every face.In the example box, this might not be too awful because the top is fairly open. But can you imagine if it was a narrow opening that made seeing inside the box a challenge in and of itself?

There’s no need to worry, however, because you can use the Knit command.

Knit is intended for stitching surfaces together. Most of the time that’s how it’s used, but you can also use the Knit command to copy a face for a surface. Knit in itself has nothing to do with minimizing the number of picks, so we still haven’t solved the clicking problem yet. That’s where the Radiate Surface command (Insert > Surface > Radiate) comes to the rescue.

This cool, super-secret tool is found inside the Knit command, but only if you use the Knit command (Insert > Surface > Knit) WITH a Radiated surface. Once you create a radiated surface, use the Knit command and select the Radiated Surface as the face you want to Knit, and you will get the option to select Seed Faces.

It’s the Radiate Knit one-two combo for the win.

Figure 4. Radiate Surface and Knit.

Now, all you need to do is pick two faces, select Radiate Surface and the face (RED) that is likely to always be there. The Knit command gobbled up all the faces connecting from the permanent face to the Radiated Surface without imposing extra clicking strain on anyone’s poor index finger. You now have a surface body in which you can remove the unnecessary face created from the Radiated Surface to thicken, and you’re all set.

Figure 5. Delete face and finish thicken.

When I show this to people, the first response is often, “Big deal, I can just use Select Tangent Faces for a Copy Surface, and I’m done.”

While you could do that, what if not all the faces are tangent? You’d have to go through clicking like crazy. What about if you need to rollback and make changes to the design? That means back to editing those failing features to in order to re-pick faces.

With the Radiate Knit technique, users don’t need to worry about missing entity errors or failing features that need those new faces.When rolling back in the design to add features and then rolling to the end of the design, there is no more crazy clicking. The Knit will continue to pickup any faces between the permanent face (RED) and the Radiated Surface, regardless of tangency.

Figure 6. Design changes.

For these design changes, I rolled back the design to a point prior to the original Shell feature. I also added a circular boss with a few chamfers included, mostly to prove to nay-sayers that tangency really doesn’t matter with this method.

I changed a fillet to a chamfer by right-clicking on the fillet feature in the DesignTree and using Convert Fillet to Chamfer, which is a pretty handy enhancement that was added in SOLIDWORKS 2017. Next, I added more fillets to all the converted chamfer edges. All told, I created 85 new faces (shown in green above) and removed 70 faces (shown in purple above).

All of these faces impact the gasket design. If I used the Copy Surface command features would fail, and I’d have to get clicking to remove missing entities and add missing geometry. As fun as that sounds, since I used the Radiate Knit combo, I was able to achieve the desired changes with zero extra clicking for the gasket.

Now all that’s left is to use Save Bodies by right-clicking on the Solid Bodies folder in the DesignTree. Now I’ve got an awesome gasket designed to fit my box every time.

For one last tip, have you ever downloaded an assembly for use in your design? How about a vendor who sends you a model that has a bunch of internal components in it? You won’t know what parts are in the interior or exterior, and they likely didn’t build the model for your needs. Instead, the sub-assemblies are probably based on how they need the model to be built.

All this extra data is going to bog down my top-level assembly performance. However, if you save that assembly as a part, you can use this technique along with the Combine feature (Insert > Features > Combine) to get exterior connecting faces to make your own simplified version of the assembly. All you need to do is Combine as many of the bodies as you can, use the Radiate Knit combo, patch up any holes with filled surfaces and create a solid when you Knit all the surface patches together. You can then save that body out as a STEP file or use Save Bodies to get a simplified part. With Radiate Knit to the rescue, you get a higher-performing part that can be used in top-level assemblies.

The Radiate Knit combo is a clever little hidden gem that I’ve used countless times to get away from too much clicking, and you should give it a try!

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