In this video, learn how to make multiple elements and create a singular element. This method works on curves and surfaces.
- [Narrator] Here I want to talk about Join. Go ahead and open the Join file from the reference documents that you downloaded. Now once I go into the Join function it's going to ask you elements to join. You can join curves together, surfaces together. You can not join curves and surfaces together. It's either curves or surfaces. Here I have several surfaces. I'm going to pick one of the elements, and if I select preview you'll notice that I get this green curve around the element that I selected to join.
This is showing me the join boundary. Now I can go through and pick individual surfaces as I see fit to join. And preview, as you can see every time I preview the boundary off of the join highlights. And as I go through, I will eventually select all of the surfaces that I want to join. Another way I can go about doing this, I'm just going to hit cancel, we'll go into Join.
And I'm going to select this surface. Rather than trying to go through and pick all of the individual surfaces one by one, I'm just going to go over to the surface in the elements to join window and right mouse click. This isn't something that's intuitive or just comes and yells out at you, this is kind of something you just kind of sort of have to know. And once I right mouse click over that element in the elements to join window, down at the very bottom I can select things by propagation type.
Basically this is saying pick everything that's tangent or pick everything that forms a sharp corner. For now I'm just going to say angular propagation. And preview. You'll notice that it picked everything that was smooth or tangent, all of these edges are smooth. There's rounds, fillets. These didn't get selected because they come to hard corners. I'm just going to cancel, go back into Join, select one of those surfaces. Right mouse click. This time I'm going to say distance propagation.
Preview, and as you can see here, all of those are now selected. There's no green boundary curve external showing us that there are any free edges. So everything has been selected, everything will be joined once I select okay. Now under here you'll see check connexity and what's called Check Manifold. These are verifying that all of elements are going to be joined into one singular element.
There are times depending upon what you're doing that you may have two, or three, or four, or 10 different elements that don't touch that you want to join. And let me just select okay and I'll show you what I'm talking about. I'm going to go ahead and create a plane, just say tangent to surface through this point. And I'm just going to create a couple of points.
Create a couple of cylinders. And this is a fairly common exercise where people will create cylinders for a whole size that they're going to use to trim out later on. So I'll just pick this point, this direction. There we go, there's one. Two. There's my third. Now when I go into Join and I pick these three individual cylinders you'll see that they don't touch. If I select preview it's going to come up with a message, Non Connex Result, meaning I have three elements in this case selected that do not touch.
Non Connex is the way CATIA tells you you have elements touching, that are not connected. This is saying, "Do you want to display diagnosis?" You can hit yes, or you can hit no, it's just going to show a little flag. Some cases you're going to want to hit yes to see where things are at, but if it's a large file this diagnosis could take a long time, and it gives you a little warning. So if you hit no it'll just go back into the join function, whereas here if I hit yes it'll say these things aren't touching. So these are little flags that I as talking about.
This is small, so it displays it quickly. Now what I can do is turn these elements off, preview, and you'll notice that I don't get that error message. What this does for me is say I have 10, 20, 30 holes that I have to cut into a part. By joining them all into one singular entity, when I go do all of the cutting I no longer have to worry about picking every single one of those, all I have to do is pick the final join, and let me go ahead and hit Okay. You'll see there, join in the tree to do my splitting with.
This is kind of nice. Join is a great tool to help manage your part or your data and what's in the part. So if I were to go ahead and use this as split, what I can do if I need to remove holes, double click on the join, find the cylinder that I don't need, right mouse click, clear selection, select okay, and now what happens is that join is just those two elements. If I hide this you'll see it goes away. So if I had used this for a secondary or tertiary function, if I use that join for that secondary or tertiary function, then those functions will just automatically update with that removal of that hole or if I have to add an additional hole I just have to update the join.
It's a very stable element. Very useful element. Another thing that' it's good for is, I'm going to double click on one of these, doesn't matter which one. As you'll see an arrow. This is the surface normal of that join. So in this case it's pointing in. So you can also control the normal direction off of a surface. In a lot of cases this is important. When you do offsets, the offsets are based off of that surface normal. When you do any kind of machining, programming, whatever it may be, those secondary, tertiary functions, downstream functions are all basing themselves off of that surface normal.
So join allows you to control that as well. Last thing I do what to talk about right now is what's called the merging distance. Talked a little bit about this in one of the earlier lectures and there's a certain default that you may have to work to, but occasionally maybe you're translating data from one CAD system to the next and you use a much looser tolerance, you may have to go in here and mess around with this merging distance. The loosest that it will go is .1, or a tenth of a millimeter. Right now it's a .001, a micron, some places have a default of a little bit higher, .05, maybe .01, and so you can play around with that merging distance to get things to join.
Sometimes you just have to do it. It's translated data or something from another system that's not joining very well and you have to use it for a split, whatever that may be. So you just open up that tolerance a little bit and let the join do what it's going to do.
- Workbenches for surface creation
- Different meanings of hybrid design
- Point, line, and plane references
- Creating sweep surfaces
- Making 3D spline curves and offset surfaces
- Joining together elements
- Using transformations
- Extrapolating curves and surfaces