Unit 8-3D Modeling

DT2510: Advanced CAD Methods

3D Modeling and Imaging

• Introduction to 3D AutoCAD• Setting Up AutoCAD For 3D• Creating a 3D Box• Editing a 3D Object• Using the View Cube

Unit 8-3D Modeling

Viewing an object in three dimensions gives you a sense of its true shape and form. It also helps you conceptualize your design, which results in better design decisions. In addition, using three-dimensional objects helps you communicate your ideas to those who may not be familiar with the plans, sections, and side views of your design.

Unit 8-3D Modeling

A further advantage to drawing in three dimensions is that you can derive 2D drawings from your 3D models, which may take considerably more time with standard 2D drawing methods. For example, you can model a mechanical part in 3D and then quickly derive its 2D top, front, and right-side views by using the techniques discussed in Mastering AutoCAD.

Unit 8-3D Modeling

To get started in 3D, you’ll need to do a little setup.

First you’ll want to switch to the 3D Modeling workspace by selecting 3D Modeling from the Workspace list in the Quick Access toolbar.

Unit 8-3D Modeling

Next, create a new file using the acad3D.dwt template. Your AutoCAD will look similar to this image.

Unit 8-3D Modeling

As a new user, you won’t need the Create Material palette to the right, so you can close it for now.

Unit 8-3D Modeling

Using Visual Styles• AutoCAD 2012 uses visual styles to control

the appearance of 3D models in the drawing canvas

• AutoCAD LT 2012 has only one visual style: 2D Wireframe. Use the HIDE command in LT to create a temporary hidden visual style that is lost when the drawing is regenerated.

• A number of preset visual styles are available that you can access from the View tab in the 3D modeling workspace or from the Visual Styles in-canvas menu

Unit 8-3D Modeling

Editing Visual Styles• Access the Visual Styles Manager from a tool in

the Palettes panel on the View tab of the 3D Modeling workspace or use the VISUALSTYLES command

• You can edit any of the properties in the Visual Style Manager to create a custom style

• You must save the custom style with a name before switching to another visual style or the customizations you made will be lost

• Double click the icons in the Visual Style Manager to apply them to the current viewport

Unit 8-3D Modeling

Using In-Canvas Menus• There are three in-canvas menus that

appear in the upper left corner of every tiled viewport

• In-canvas menus do not appear in floating viewports

• Access viewport controls, view controls, and visual style controls from in-canvas menus

• Use in-canvas menus as alternatives to the VPORTS command, ViewCube interface, and Visual Style Manager

Unit 8-3D Modeling

Visual Styles• Use the Wireframe visual style

when working with line work or isolines in 3D

• Use Shaded or Shaded with Edges to perceive surfaces or surfaces plus line work

• X-ray mode is a combination of all visual styles having qualities of shaded surfaces, visible edges, and transparency

Unit 8-3D Modeling

Working with Tiled Viewports• Use the VPORTS command to

open the Viewports dialog box where you can configure tiled viewports for working in 3D

• You can switch between tiled viewports in the midst of any command so you can start a command in one viewport and end it in another

• Tiled viewports allow you to specify 3D points without having to use more advanced point filters (for example, .xy, .yz, or .xz)

Unit 8-3D Modeling

Using the ViewCube• The ViewCube hides a great

complexity in a simple interface• You can access 26 different preset

views using the ViewCube itself: 6 faces (top, bottom, lefft, right, front, and back) plus 8 corners, plus 12 edges

• Drag the compass to rotate about the WCS z-axis

• The ViewCube reflect the orientation of the current UCS while the compass remains rooted in the WCS

Unit 8-3D Modeling

Using Cameras• Use CAMERA to create a

perspective view with an isometric overview

• Select the camera object and the Camera Preview dialog box appears showing you what the camera “sees”

• Use the camera object’s grips to aim it.

• You can change the camera’s field of view (equivalent to lens length in physical cameras) with four grips

Unit 8-3D Modeling

Using SteeringWheels• SteeringWheels are used in many of

Autodesk’s 3D applications so learn the interface and you’ll be able to navigate in AutoCAD, Revit, Inventor, and 3ds Max

• Click and hold any of the tools on the SteeringWheel to use

• Drag forward to walk forward through a space, drag to either side to turn that way

• Use Rewind to move backward through a navigation history

Unit 8-3D Modeling

Saving and Restoring Views• Use the VIEW command to save views

for later reuse• You can save views in model space and

in layouts• Views can store much more than

camera position and orientation data• Views can optionally store a layer

snapshot, visual style, current UCS, live section, and viewport background

• Views can be either static, cinematic (like an animated slideshow), or a recorded walk that can be played back through ShowMotion on the Nav bar

Unit 8-3D Modeling

Revolving Surfaces and Solids• An open path can be revolved around

an axis or line to generate a surface• A closed path can be revolved around

an axis or line to generate a solid• You can make wine glasses, vases,

architectural urns, spheres, domes, wheels, and so on with REVOLVE

• Anything turned on a lathe would be revolved in AutoCAD

• Revolved objects do not have to be turned full circle; partial revolutions are also possible by specifying less than 360 degrees

Unit 8-3D Modeling

Sweeping Out 3D Geometry• SWEEP works by pushing a profile along

a path• If the profile is open the swept object will

be a surface• If the profile is closed the swept object

will be a solid• The path can be either open or closed• Use SWEEP to create stadiums,

handrails, curbs, architectural moldings, and so on

Unit 8-3D Modeling

Extruding 2D Objects into 3D• The term extrude means to push forward

as through a die. EXTRUDE works by pushing a cross section along a straight path

• EXTRUDE has a Taper option that scales the cross section along the extrusion path

• Extruding an open cross section generates a surface

• Extruding a closed cross section generates a solid

Unit 8-3D Modeling

Lofting 3D Objects• LOFT allows you to create surfaces and

solids from a series of cross sectional profiles

• A special grip appears after you select the cross sections with a menu that allows you to determine how the surface is stretched across its cross sections

• The term normal refers to the orientation of the surface being perpendicular to the cross sections

Unit 8-3D Modeling

Boolean Operations• Named after mathematician George

Boole, Booleans are solid editing tools

• Booleans include UNION, SUBTRACT, and INTERSECT

• By performing a Boolean union, the precise intersection between solids is calculated and represented in wireframe

• You can use solids to cut potions away from other solids with SUBTRACT

Unit 8-3D Modeling

3D Transformations• You can use 3DMOVE, 3DROTATE, and

3DSCALE to transform objects in 3D• 3D transformations use gizmos that

allow you to easily pick the axis you wish to transform along or around

• You can use the regular MOVE, ROTATE, and SCALE commands in 3D by first manipulating the User Coordinate System

• Only one UCS is available in AutoCAD LT

Unit 8-3D Modeling

Working with Radial Symmetry• For radial symmetric geometry it

makes sense to move the geometric center to the origin point of the user coordinate system

• Transformations such as MIRROR and ARRAY are much easier when they start at the origin point

• For example, you can easily type 0,0 rather than having to snap to the center of an object with radial symmetry

Unit 8-3D Modeling

Using Shell and Presspull• SHELL creates an wall that extends

inward from all external surfaces of a solid and leaves a void within

• You cannot see into the void within shells without cutting a hole through the shell itself

• You can use SUBTRACT or PRESSPULL to cut a hole in a shell

• PRESSPULL either creates or subtracts geometry depending upon whether you press (remove) or pull (add) geonetry

Unit 8-3D Modeling

Smoothing Meshes• Mesh objects are composed of a

discrete number of flat faces• You can convert solid objects to

meshes by smoothing them• Smoothing means

tessellating and transforming the faces which compose a mesh

• Smoothing can give a machined object a curvilinear, organic look

• Mesh objects can be converted back into solids for engineering analysis

Unit 8-3D Modeling