- Let's take a look
at how we can use some construction geometry
to improve our sketches.
Now, right here on the screen,
you can see we've got a whole bunch of dimensions here
and we do have a fully defined document.
So there's nothing wrong
with what I have here on the screen.
It just looks messy.
And there's a whole bunch of duplicates.
Look on the left hand side here.
You can see I've got a one inch dimension.
I got the same thing right over here
on the other side, right?
Same thing over here.
I got a two inch dimension, two inch dimension over here.
Let's see if we can improve a little
of this by using some construction geometry.
So the first thing I'm going to do is delete everything
on this side over here.
So let's get rid of this one.
Let's get rid of that one.
Let's get rid of this.
Okay.
Down here at the bottom of the screen,
notice we're not symmetrical, right?
We have the origin here on this left corner.
We prefer to have it right in the middle.
So let's go ahead and delete that relationship too.
And now what I want to do is I want to grab some center lines.
So I'm going to grab a line
from here to there, place that in there.
So that's going to automatically use this one inch dimension
for both of those,
because we have a horizontal relationship right here.
Then let's go ahead and tie in.
Again, if we're already in that line command
or the center line command,
let's tie in from the midpoint here
to the midpoint there.
Pretty handy.
In fact, let's come all the way
down to here and then tie in over here.
So I've got a couple things
and I can say this line here and this line up here,
let's hold (indistinct) control
and say these guys are equal.
All right.
And what that means is
that I don't really need this dimension anymore.
Okay.
Two inch and two inch, get rid of the second one.
Why type the same dimension twice,
if we know it's exactly the same, same thing over here.
Get rid of that one.
Let's just say this line here.
Hold (indistinct) control, this line, this line, and this.
These guys are all going to be equal.
Okay.
Over here, let's grab that whole sketch now
and make the midpoint of this point here.
Hold (indistinct) control.
Select that line and say, 'make midpoint'.
Now you can see that it's looking a little bit cleaner
and it's a little bit more robust.
If in fact, if I wanted to change something
like this dimension here to something like 3.0,
notice everything automatically grows.
It stays in the center,
way nicer than just the way we had it before.
Over here, one inch, one inch.
Redundant.
Again, let's get rid of that, right.
Let's say this circle here,
hold (indistinct) control, this circle right over here
and let's make them equal.
All right.
So if I change one to like 1.5, they both change.
If I change it back to one, they both change.
If I change this back to two,
everything adjusts and looks pretty good.
Okay.
So over here, this dimension is pretty much needed, right?
And we need to tell it how tall it is in this section here.
And this two inch dimension here is also pretty much needed.
We do need to specify how far we're off this edge here.
But in this case, it happens to be the same distance
from this line here to this line.
What I could do is delete that
and I can make one more little center line here.
And that center line is from here over to here.
Right.
And okay, let's go ahead
and create one more.
From here down to the midpoint there.
So I could say, "Hey, this line and that line,
those guys are going to be equal,'
which automatically establishes.
And now I've got really only these four dimensions
to define the entire shape.
So now you can see my sketch is just a lot cleaner.
It's a lot more dynamic.
And if I change one thing,
a lot of other things follow along.
So I'm only changing one
of those items versus changing multiple things
with all the same dimension, right.
So if you have two holes and they're both one inch,
why change it two places when you can change it
just one place?
(Indistinct), they're both fully defined sketches.
What we started with from the beginning
and what we have now are both fully defined.
This sketch though is just a lot more robust.
So definitely keep this in mind when you're working
in designing and sketches.
Use some of those relationships,
use some of those things, like symmetry
in your design so that you're doing less work
that's better work in the long run.