3-15: 3D CAD Practice and Exercises

3-1 INTRODUCTION TO 3-D

 

3-9 ADDING MATERIALS

3-2 ISOMETRIC DRAWING

 

3-10 PRIMITIVE SOLIDS

3-3 WORKING IN 3 DIMENSIONS

3-11 BOOLEAN OPERATIONS

3-4 VIEWING 3-D OBJECTS

3-12 CHANGING FROM THE WCS TO THE UCS

3-5 BASIC WIREFRAME MODELS

3-13 MAPPING MATERIALS

3-6 LINE THICKNESS

3-14 CREATING NEW MATERIALS

3-7 REGIONS AND 3-D FACES

3-15 EXTRA PROJECTS AND A TUTORIAL

3-7a MORE EXTRUDING & LOFTING

 

3-16 PUTTING IT ALL TOGETHER - MODEL A BUILDING

3-8 REVOLVED OBJECTS

3-17 INTRODUCTION TO RENDERING AND LIGHTING

  3-18 CREATING ANIMATIONS IN AUTOCAD

Topics covered in this Lesson:

Review and Practice of 3D Concepts

 

There is only one way to get better at AutoCAD and that is to practice. In 3D, you not only need to know the commands, but also how best to use them. As you start drawing in 3D, you may start looking at everyday objects and think about how they would be drawn. Look at some 3D drawings online and figure out how they were done.



EXTRA PROJECT - A

If you have finished the previous exercises and would like more practice, try this:

Sketch out a simple coffee table on paper. Add the basic dimensions. Draw this in AutoCAD using any 3-D method. Once you've done this, draw another lamp and place it on the table. Use rotate3d if you need to turn it right-side up. Find a good view to display what you have drawn. Add materials.

 

EXTRA PROJECT - B

Take your file from Lesson 3-7 that gave you a solid model and use the fillet and chamfer commands to add some smoother corners to your chair.

 

Fillet 3D Model

 

EXTRA PROJECT - C

Draw the object that you draw in the isometric lesson in 3-D using extruded regions. You will have to first create the outline, then the circle. Turn both objects into regions. Subtract the circle from the outline to have one remaining region. Extrude this to get your solid object.

 

TUTORIAL - CREATING A 3D OBJECT FROM A 2D PROFILE

For this tutorial, you should be familiar with these 3D commands: region, extrude, union, subtract.

This tutorial shows you a method for quickly turning 2D shapes into 3D objects. One of biggest problems with 2D objects is that they are not always drawn properly. This is something that should have been addressed when it was first drawn, but here is a way of working around it.

First lets start with a basic shape (remember the array command). This is the profile for a gasket. It is drawn in 2D with lines, arc and circles.

 

 

Assignment 3

 

Let's hope it was well drawn, meaning no overlapping lines, gaps, etc. Copy the objects over to the side for the next section.

 

Here is how you turn it into a 3D object easily. Start the REGION command. Draw a crossing window around the whole area and press enter. Once you have your regions created, you can extrude them. Start the EXTRUDE command and select all objects. Press enter and enter your extrusion height and taper angle. When these are extruded, begin your SUBTRACT command and first select the larger object first (to be subtracted from), press enter then select all the other objects and press enter. When you change to your SW Isometric view, type in HIDE (enter) and you should see the object as shown below.

 

Extruded 3D object

 

 

Remember that you can always work in your SW Isometric view to see the progress of your 3D work.

There is one problem when using the REGION command. If have two lines that are overlapping, AutoCAD can not make a region out of the objects. You could search until find the offending line, but there is an easier way.

 

Here's this approach:

Now look at the copy of the shape that you made you earlier. Instead of using the region command, use the BPOLY command. This command works similar to the HATCH command in that it finds the boundaries for you. Start the command and you will see this dialog box come up:

 

BPOLY Dialog Box

 

Accept the defaults and press on the Pick Points button. In your drawing screen, pick an internal point as if you were hatching it and then press enter.

 

Now start your EXTRUDE command and select the last (L) object created and extrude it. Now begin the SUBTRACT command and select the outside object, (press enter) then use a crossing box to select everything else and press enter. Use the HIDE command to ensure that everything is as it should be.

 

Video: Review of exercises in Lesson 3-15

 

 

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For Further Thought:

When I taught 3D AutoCAD in a classroom, I let each student come up with their own idea for a final project. Some had specific ideas what they wanted to draw, others needed help. But the main goal was to think of something and then figure out how to draw it. Some projects I remember were a boat, a keyboard and a guitar. Each one used some of the tools in this level. All of them had one thing in common. They all required planning on the part of the student to make the project happen. We discussed which tools might work best, which ones wouldn't work (and why) and then we came up with a plan. It was great experience for the student and I had a lot of fun thinking about designs I hadn't considered before. Look around your 3D world and start thinking about how you would draw the world around you.


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