- [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.