Activity 23: Evaluate the Part Using Measure

All right,

believe it or not,

we have made it to the last video in this

series of videos that has been designed to expose you

to a variety of CAD operations and to various

ways to interact with the CAD system.

In this last video, we're going to do Activity 23,

which is to evaluate the part you created

using measure.

OK,

so looking here at the instructions,

we want to verify that the part that you have created has the correct geometry.

And to do this,

the shape and size of the features must be verified,

plus their placement relative to each other.

Now, a mass properties evaluation is a quick way

to verify that everything is the correct size.

But it does not indicate if the features are correctly placed.

For example,

all 4 bolt holes could be in a line and the mass would be correct,

but the part would be wrong.

The measure command helps with this by allowing us to measure entities

and the distances between entities.

So, we're gonna use

the measure command

to verify the correctness of the part

that we have created.

OK,

looking at the next page of the instructions now,

we're going to

measure a variety of things

and the way that I'm gonna handle this video right now

is

I'm going to take a look at this list

and then I'm gonna just gonna memorize as many of them as I can,

OK,

and then

I am going to just

chip through a few of them and then leave the rest for you to take care of.

OK,

so we want to look at the radius of the outside corners.

These should be 20.

Remember the diameter was 40,

but now we just have a radius,

OK?

We want to not just make a measurement but compare it to the actual number,

OK?

The radius of the inside corner should be 16,

the diameter of the bolt hole should be 20,

the length of the gasket should be 268,

the overall width should be 152,

the length of the rectangular cutout should be 168.

That's right,

because I remember the offsets being 50 at the top and at the bottom,

which is why we have 268 here and 168 here.

The

width should be 128.

The thickness of the gasket should be 2 millimeters.

The distance between holes,

OK,

should be 96 and then 222

between the vertical ones.

OK,

so now we're going to do that.

OK,

gonna come down here into this.

He is our part,

down here is the measure

details.

OK,

can I come down here and click on this,

and we're gonna just start checking some things.

This should be 20 radius.

And it is 20 radius.

This should be a 20 diameter.

And where do we see it?

Where do we see it?

Oh,

actually I have two entities selected,

so now it's attempting to

do this.

So, spacebar will clear all of my selections.

This is actually a very valuable thing to know.

OK,

my diameter here is 20,

that's good.

Spacebar will clear that.

I can click on this one, should be 16 and it is,

clear that,

OK,

our overall thickness should be 2 millimeters and so watch as I click this face,

flip it around and click this face,

and we should see 2 millimeters,

which is what we see,

clearing those.

And let's get some of our other dimensions.

OK,

now there's a couple of ways to do this particular one that I'm gonna show you now,

and we should be a little bit careful with it,

OK?

If

I want to know what the distance is between this plane,

and

this plane,

it should be 268,

remember that?

OK,

268.

OK,

and we are 268,

that's right.

It's best if I do it this way,

where I actually have grabbed the planes,

OK?

Now,

alternatively,

hitting clear,

I could go and get this line.

OK.

And I could go and get this line that's down here and I'll get 268,

which is what we got.

But I could

accidentally

choose

this corner.

Should be that edge and this edge,

and now I don't have 268 anymore because

I'm now getting sort of like

a hypotenuse leg

distance between them.

So,

we should be careful with that,

OK?

So

to that end,

oops,

I've just canceled out of that,

that's OK,

I can just open it back up.

I'm gonna check this,

which should be 168.

As I said,

I'm not gonna chip through all these right now.

It

is 160,

I just got the ones that I could remember

in my head.

And

I'll leave it to you

to figure out the other ones,

OK?

So,

that's that piece.

Oh,

we need to get some center-to-center distances,

and this one's a little bit hard,

so

I'm gonna talk about this one for a minute.

Let me scale or let me get space to get out of those.

If I click this circle and this circle,

I will get a number of measures here

including

center-to-center distance which should have been

96

and so that's right.

Now if

I

spacebar out of this to get out of that selection,

we should have

222

to this one,

center-to-center distance 222,

OK?

So, that's how we make those measurements and that's how we verify

that the part is good.

OK,

all right,

now we're gonna go on to our next set of instructions,

OK,

and see what we have

going on here,

OK?

Similar measurements

can be made to check the placement of circles and rectangles relative to the origin.

But we won't spend time to do that now.

Instead, we'll check to see

that the cutouts are placed correctly using

the mass moments,

which

is how your CAD models will be submitted,

if

you were to submit them in the course,

OK?

Now

how

how are we gonna do that?

Well,

these

are the numbers that we should be looking at.

So, let's just see if we can get some of these.

We know the mass number,

that number has appeared so many times in these videos.

The volume number,

you know,

these

are going to be harder

to memorize,

but we're just going to get this one down here,

which is

961,708.

908.

Can we remember that?

I'm not sure if we can,

OK.

But we're gonna come over here and I'm gonna show you how to do this one.

OK,

we're gonna get into here,

we're gonna hit our mass properties and when we do hit our mass properties,

we are going to see

the mass,

we're gonna see the volume,

we're gonna see the surface area.

If we have a model that we know is right,

we can compare these numbers.

We can also see the largest mass moment of inertia is this one which is 961,708.908,

which is the number

we were just referring to

a second ago.

So, two things are going on with this

activity.

We want to measure the location and size of things,

in

particular,

the size of things is what we did in the first activity.

The location

relative to the origin

is,

you know, that's even more tedious and so one of

the things we can do is look at the mass properties

and then we can look at the

mass moment of inertia,

and if we do that we can know

that we not only have the right size of the

cutouts, but the cutouts are in the right place.

So, throughout the course, we will largely be checking

your mass,

your volume,

your surface area,

and

the principal

moment of inertia,

OK?

And what's going on there is that just means the largest

moment of inertia that we're gonna look at in the system,

OK?

With those four things,

it is believed

that your model will be right,

OK.

So, you can imagine

if all we checked was the mass,

you could just make a sphere

of a particular mass and then it would appear right

to us, but now we actually want it to have

the right mass,

the right volume,

also the right surface area,

and we can know that all the cutouts and

other such things are right cutouts and extrusions and whatever

are right

when the mass moment of inertia is right.

OK,

you've done an excellent job sticking through

all of these activities.

What you need to know is that you just learned a

whole lot about how to interact with the CAD system.

Now you need to tuck those away in your head

as things in your toolbox, so that when it's time

to create your own geometry and your own designs,

you have all these things you can turn to trims

and extends and patterns, both feature patterns and sketch patterns, and

all kinds of things like this are now in your toolbox that

you're gonna need to use

in

the future. If you need to come back to the videos,

that's not a bad thing

to refresh on a few things

or to use the Onshape learning center,

which also has a lot of things to teach you about

relative to these kinds of operations.