# DAT Top Front End Tutorial- Height, Width, and Depth

The Top, Front, End view section of the Dental Admissions Test is a section that many students struggle in. Doing well in this section requires a good eye for detail and experience with orthographic projections. One thing that students must recognize when analyzing these problems is that the Top View, Front View, and End View give away key information that you may not recognize at first that can be the key to solving these problems, and that key information is the height, width, and depth. Some students do recognize these features subconsciously and are able to reason through these questions to find the correct answer, however they don’t fully understand that they used this technique, and just attribute it to “Using Their Perceptual Ability”. I will break down this technique to help give you an edge when completing perceptual ability problems.

#### Perceptual Ability Practice Resources

Listed below are the top 3 most popular perceptual ability resources for explanations and practice problems.

## The 3-D Object

When looking at an object projected in 3-D you can easily distinguish between the height, width, and depth of that object. You can also distinguish the height, width, and depth of structures within that object. Lets Try it out. Look at the object above and find the height, width, and depth of that object, also try and find the height, width, and depth of the hole in that object as well.

Now that you have given it a try here is the answer below:

As you can see, you can easily find the height, width, and depth just by looking at this 3-D model. But how can you find the height, width, and depth by looking at the top, front, and end view? I will show you below using orthographic projections of the top, front, and end view of the 3-D object I used above. For simplicity I have converted height, width, and depth to:

Height= Y

Width = X

Depth = Z

## The Top View

The Top view is important for identifying the Width, and Depth of an object. Because you are looking straight down on an object the height cannot be determined. If you have trouble with this concept try imagining you have a small rectangular box. You put this rectangular box on the ground, stand up and look down on it so that your eyes are lined up with the center of the box. Now try and determined the height of that box. You can’t. The only way you can determine the height of that box is to pick it up and bring it eye level so you are either looking at the front or the end view.

Using the 3-D model above I have created what you should see when viewing the Top View of that model, try and determine the width and depth of the hole and the object using the projection below:

You should have come up with something like this:

Width = X

Depth = Z

## The Front View

The Front View is important for identifying the width, and height of an object. The depth cannot be determined because you are looking right at the object. If you have trouble with this concept consider this example; Imagine you have a small rectangular box. You then take that rectangular bring it up to your face so that the middle of the box is parallel with your eyes, make sure the box is close enough to your eyes so you can see the edge of the box with the edge of your peripheral vision. Now try and determine the depth of the box, you can’t. The only way you can determine the depth of the box is to turn it and view it from the top or side.

Using the 3-D model shown at the beginning of this tutorial I have created a front view projection of the object. Try and find the Width and height of the object and the hole looking at the projection below.

You should have come up with something like this:

X= Width

Y= Height

## The End View

The End view is important for identifying the Height and depth of a projection. The width cannot be determined using the End View, because you are looking at the end and cannot determine the width. If you have problems understanding this concept imagine you have a small rectangular box. You pick it up, turn it to its end, and look directly at the box so your eyes are parallel with the center of the box, and the edges of the box are just to the end of your peripheral vision. Now try and determine the width of that box. You can’t, the only way you can determine the width of that box is to view it from the front or top.

Using the 3-D model shown at the beginning of this tutorial I have created a end view projection of the object. Try and find the depth and height of the object and the hole looking at the projection below:

You should have come up with something like this:

Z= Depth

Y= Height

## Using the Height, Width, and Depth

Now that you have seen how you can determine the height, width, and depth of the object and structures within the object I will show you how you can use this to your advantage to solve Top front end view problems on the Dental Admission Test. You can use the Height, Width, and Depth technique to narrow down your answer choices or possibly find the correct answer. Lets take a look at the practice problem shown below:

#### Step 1: Go straight to the Answer and look for obvious differences in height, width, and depth between the answer choices.

The obvious differences are the size differences of the objects, A & C have a larger depth than B & D. We know that A & C are the same depth, and B & D are the same depth. We know that only one out of the two depths is the correct answer, so we can eliminate A & C or B & D. We know from the tutorial above that the Front View cannot give us a depth measurement, but the End View can, so we will use the End View to eliminate some choices.

As you can see below by looking at the end view we can determine that the depth of A & C do not match up with the depth depicted by the end view. However the depth of B & D do match up with the depth depicted by the end view as shown in the color coded diagram below:

Z= Depth

Now we can eliminate choice A & C:

Now Lets Focus on B & D.

#### Step 2: Look at the Answers and look for not so obvious differences in Height, Width, and Depth in substructures (EX: Holes, blocks, etc.) in the answer choices.

As we can see the only real difference between B & D is this depth of the block substructure in the very top right corner of the figure circled in blue in the picture below:

Now what projection  will give us the correct depth of the block? The End View is the only projection we can use to determine the correct depth of the block, so lets compare the block of the End View to choices B & D.

Z = Depth

Using the Height, Width, and Depth technique we easily determined that B was the correct answer, because the block on D had too large of a depth.

Good Luck on the Dental Admission Test!

Check out some of the resources below for practice perceptual ability problems and tutorials:

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