cad绘图基本(Basic cad drawing)

cad

绘图基本（

Basic cad drawing

）

12, three-dimensional grid (3dface): This method is too

impractical (slightly)

The

entity

model

is

the

easiest

three-dimensional

model

to

use.

Using the entity model of AutoCAD, three-dimensional objects

can be created by creating rectangular, cone, cylindrical,

sphere, wedge and torus entity models. These shapes are then

merged

to

find

their

difference

or

overlap

(overlapping)

parts,

combining

to

produce

more

complex

entities.

You

can

also

create

an entity by extending a two-dimensional object along a path

or

by

rotating

it

around

the

axis.

With

Mechanical

desktop,

you

can also define parameterized entities, preserving the

association between three-dimensional entities and the

two-dimensional views that are generated from it.

Warning

！

Because three-dimensional modeling can construct

three-dimensional models in different ways, and each editing

method has different effects on different models, it is

recommended

that you

do

not

use

the

modeling

method

in a

mixed

way. There can be only limited conversions between different

model types, from entities to surfaces or from surfaces to

wireframe. However, you cannot convert from a wireframe to a

surface, or from a surface to an entity.

13, Rotary surface (Revsurf) Rev: Constructs a polygonal grid

that

is

approximate

to

a

revolved

surface

by

rotating

the

path

curve or section (Straight, Circle, arc, ellipse, elliptical

arc,

closed

multiple-segment,

polygon,

closed

spline,

or

ring)

around the selected axis.

14, translation surface (Tabsurf): a surface that is made up

of a initial lines (the beginning of the surface) along the

specified

vector

(the

length

of

the

initial

edge

translation).

Note: The translation surface can be interpreted as a

predefined

initial

trajectory

curve

(straight,

arcs,

circles,

spline curves, two-dimensional multiple-segment lines,

three- dimensional multiple-segment lines) are translated

(stretched) along a stretched trajectory of a specified

distance and direction (the surface and the trajectory line

remain two different entities).

15, Straight line curve (Rulesurf): Refers to two lines or

curves

specified

by

the

relative

two

sides,

by

these

two

sides

generated by a three-dimensional grid of the surface, the

surface in the two relative lines or curves between the grid

is a straight line.

1 The curves used to create straight- grain surfaces can be

straight lines, points, arcs, circles, spline curves,

two-dimensional

multiple- segment

lines,

and

three-dimensional

multiple- segment lines, and different entities can also be

grouped together.

2

The

style

density

of

the

straight

grain

surface

is

determined

by the system variable SURFTABL1 and SURFTABL2.

System variables SURFTAB1 and SURFTAB2 system variables

control the grid density (number of tessellation) in M and n

direction respectively [between 2 and 32766].

16,

Boundary

curve:

After

determining

the

4

edges

of

the

surface,

and

then

through

the

4

edges

to

generate

the

surface

(the

4

edges

used to generate the surface must be the end-to-end closed

graph.) The curve as the edge can be straight line, arc,

multiple segments, etc.).

Note: (1) 3DMESH create three-dimensional polygon mesh.

(2) Edgesurf creates a three- dimensional polygonal grid of

approximate cons patches.

(3) Pface creates a three-dimensional mesh with vertex

vertices.

(4) Revsurf creates a revolved surface by rotating the path

curve or section around the selected axis.

(5)

Tabsurf

creates

a

translation

surface

polygon

mesh

by

path

curve and directional vector.

Eight, view toolbar.

Entity description

An entity object represents the volume of an entire object.

In all kinds of three-dimensional models, the entity

information is the most complete and the least ambiguous. The

more

complex

entity

shapes

are

easier

to

construct

and

edit

than

wireframe and grids.

There are three ways to create an entity:

1,

according

to

the

basic

entity

form

(cuboid,

cone,

cylinder,

sphere, ring body and wedge body) to create the entity;

2,

stretch

two- dimensional

objects

along

the

path

to

create

the

entity;

3.

Create

an

entity

by

rotating

two- dimensional

objects

around

the axis.

After

you

create

entities,

you

can

create

more

complex

entities

by combining these entities. These entities can be merged to

obtain

their

difference

or

overlap

(overlapping)

portions,

and

the entities can be further refined by rounding, chamfering,

or modifying the color of the edges. Because you do not need

to draw new geometries or perform Boolean operations on

entities, it is easier to manipulate the faces on the entity.

For

more

information,

see

Creating

composite

entities.

AutoCAD

also

provides

commands

for

cutting

entities

into

two

parts

and

obtaining two-dimensional sections of the entity (see

modifying three- dimensional entities). As with the grid, the

entity appears as a wireframe before it is hidden, shaded, or

rendered.

The physical characteristics (volume, inertia moment, center

of gravity, etc.) of the entity can be analyzed, the data of

the

entity

object

is

exported

to

the

NC

milling

machine

for

use

or fem (finite element method) analysis, or the entity is

decomposed into a grid and a Wireframe object. The Isolines

system variable controls the number of element lines used to

display the curved part of the wireframe. Facetres System

Variables Adjust the smoothness of the shading and blanking

objects.

IX. Entity toolbars: (Entity objects represent the volume of

an entire object)

There are three ways to create an entity:

1.

Create

an

entity

based

on

the

basic

solid

shape

(cuboid,

cone,

cylinder, sphere, torus, and wedge):

Click

on

the

command,

enter

the

value,

click

on

the

view,

click

the coloring.

2, stretching the two-dimensional object along the path,

3), or rotate the two-dimensional object around the axis.

1. Create cuboid Box:

2,

create

the

sphere

(sphere):

With

this

method

to

draw

the

ball,

the entity is in the form of wireframe to display, wireframe

density by the system variable Isolines control, the initial

value of the variable is 4, the larger the value of the line

box more dense.

3. Create cylindrical body (Cylinder)

4. Create cone (cone)

5. Create wedges (Wedge)

Note:

The

wedge

form

created

by

this

command

is

long,

wide,

and

high, which is parallel to the 3 axes, and can only be changed

by using the 3D Edit command.

6. Create a ring (Torus)

Note:

the

diameter

or

radius

of

the

ring

refers

to

the

diameter

or radius of the centerline of the torus.

7. Create stretch (extrude) Ext: Create an entity by adding

thickness, specifying a height value and inclination, and

stretching the object along the specified path. ' Stretching

'

is

especially

useful

for

objects

that

contain

rounded

corners,

chamfer angles, and other details, otherwise it is difficult

to replicate these details if they are not on a section.

1 The objects that can be stretched and closed are: Many

segments, polygons, rectangles, circles, ellipses, closed

spline curves, ring and surface fields.

2 objects that cannot be stretched include objects within the

block, multiple segments with intersecting or transverse

segments, and multiple segments that are not closed (a

multiple-segment line should contain at least 3 vertices but

not more than 500 vertices).

3 below are the steps to stretch along the path:

(1) Input command: Ext

(2) Select the object you want to stretch, right-click

(3) Input P (path)

(4) Select the object that is the path.

Note: A two- dimensional entry must be a face field once.

8. Create a rotation (Revolve) Rev: Rotates a two-dimensional

graphic around a specified axis to form a three-dimensional

entity (rotatable closed multiple-segment lines, polygons,

circles, ellipses, closed spline curves, ring-and-surface

fields).

1 The three-dimensional entity generated by the rotation of

two-dimension graphics is also represented by grids, and the

grid density is controlled by the system variable Isolines.

2)

(the

object

contained

in

the

block,

a

multiple-segment

line

with

intersecting

or

self

intersecting

segments,

which cannot

be rotated)

9,

Cut

(slice)

SL:

Cut

the

existing

entity,

and

then

remove

the

specified part to generate a new entity (half or all of the

profile can be retained). The split entity retains the layer

and color attributes of the original entity.

Note: The default method for the split solid is to specify a

shear plane at three points, then specify the portion to be

retained,

or

to

define

the

clipping

plane

by

other

objects,

the

current view, the z-axis, or the XY, YZ, and ZX planes.

10, Cutting (section) SEC: After cutting the effect is the

entity, and cutting the effect is the surface (surface).

11. Interference (Interfere) creates a three- dimensional

composite entity (equivalent to the intersection of Boolean

operations) with the common parts of two or more

three-dimensional entities

1), Input command Interfere

2), click on the Object

3), right key

4), click on the next object

5), right button.

12, set graphics (Soldraw) slightly

13, set the view (Solview) slightly

14, set configuration (Solvprof) slightly

X. Entity editing toolbar

Note: Boolean operation: in three- dimensional drawings,

complex

entities

are

often

not

generated

at

once,

generally

by

the relatively simple entity through the Boolean operation

combination. Boolean operation is to a number of

three-dimensional entities to find and, the difference, the

intersection of the operation, so that they are combined, the

final

form

of

the

user

needs

the

entity

(Boolean

operations

on

the three-dimensional entity is also applicable to the

two-dimensional

surface,

but

the

surface

and

wireframe

can

not

be Boolean operation)

1,

and

set

(Union)

Uni:

Merge

two

or

more

than

two

entities

into

a

single

entity

(you

can

merge

entities

that

are

not

in

the

same

area or space).

2,

Difference

set

(Subtract)

Su:

Subtracts

another

entity

from

one entity and eventually obtains a new entity.

1 input command: su

2) (Select objects in order) first select the object to be

retained, right

3) Select the Subtracted object and the right key.

Note: The retarded entity and the entity as the meiosis must

have a public part.

3,

Intersection

(INTERSTCT)

in:

Calculates

the

overlap

area

of

two or more existing faces, the volume of the public portion

of two or more existing entities, leaving the public part and

deleting non-public parts.

4, stretch surface: stretch the face of the selected

three-dimensional entity object to a specified height or

stretch along a path (multiple faces at one time).

1 when stretched at the specified height and tilt angle, the

slope of the stretching can only be between 0-90 degrees, and

the

entities

that

use

the

surface

stretching

will

return

to

the

original entity and the two as a whole.

2

when

stretched

by

stretching

path,

the

stretched

path

cannot

be

tangent

to

the

contour

of

the

extruded

surface

(the

stretch

path can be straight, circular, arc, elliptical, elliptical,

multiple,

or

spline)

the

stretching

path

cannot

be

in

the

same

plane as the face, nor can it have a high curvature portion.

The extruded surface is stretched from the section plane and

ends at the end of the path and the section perpendicular to

the path. An endpoint of the stretch path should be on the

profile

plane,

otherwise

the

AutoCAD

system

will

automatically

move the path to the center of the section.

If

the

path

is

a

spline

curve,

the

path

should

be

perpendicular

to

the

section

plane

and

one endpoint

should

be

on the section

plane. If the path does not have a vertical section, AutoCAD

Rotates

the

cross

section

until

it

is

vertical.

If

an

endpoint

is on a section, the section rotates around this point,

otherwise AutoCAD moves the path to the section center and

rotates the section around the center.

3 input positive values can be stretched along the positive

direction (usually outward), and a negative value can be

stretched

along

the

negative

direction

(usually

in

the

inline).

(The extrude in the Entity toolbar is used to position

two-dimensional

graphics,

and

the

drawing

in

the

Entity

editing

toolbar is used to stretch three-dimensional objects)

5.

Moving

surface

(Solidedit):

Moves

the

faces

of

the

selected

three-dimensional

entity

objects

along

the

specified

height

or

distance (one can select multiple faces at a time, and if all

the selected moving surfaces are moved across the entity).

Note:

When a

moving

surface

is

the

outer

surface

of

an entity,

the movement of the surface is essentially equivalent to the

surface stretching (the surface movement is not simply moving

the

solid

surface,

it

is

a

process

of

the

solid

regeneration).

6, offset surface: Evenly offset by specified distance or by

specified point.

Note: 1 The offset (value) is determined by the positive and

negative direction of the surface, and the direction of the

surface

to

increase

the

area

of

the

entity

is

offset

(outward)

and vice versa.

2 When a surface is moved, the adjacent surface must be

displaced at the same time.

7, remove the surface: not all the physical surface can be

deleted, can be deleted on the surface of the entity include:

the

internal

surface

of

the

entity

(that

is,

the

surface

of

the

hole inside the solid), round and reverse angle.

For

example:

if

the

surface

of

the

hole

in

the

entity

is

removed,

the essence is to fill the hole.

8.

Rotating

surface:

Rotating

one

or

more

surfaces

or

parts

of

an entity around a specified axis

Note:

Only the

inner

surface of the

entity can rotate, and the

outer surface of the entity cannot be rotated.

9,

tilt

Surface:

In

accordance

with

the

specified

direction

and

angle of the tilt.

Note: The tilt angle must be between 90-90 degrees; the

direction

of

the

tilt

is

determined

by

the

selected

base

point

and

the

Order

of

the

2nd

(along

the

selected

vector)

(base

axis).

The positive angle will tilt the selected surface and the

negative angle will tilt outward.

10. Copy face: Copy the surface as a face field or body (the

copied surface cannot be boolean operation).

11.

Coloring

Surface:

Modifying

the

color

of

the

solid

surface.

Note:

When

the

physical

surface

is

modified

to

a

certain

color,

the

wireframe

of

the

surface

will

also

change

to

the

color

that

is being given.

12, copy Edge: Copy three-dimensional edge (all

three-dimensional solid edges are copied to a straight line,

arc, circle, ellipse or spline curve).

13, Edge Coloring: Modify the color of the edge.

Note: 11, 12, 13, 14 are

14, Imprint: In the selected object embossed an object.

Note: 1 The mark on the three- dimensional entity essentially

does not change its original shape and volume, but adds or

depicts some graphics on its surface. Once a target is carved

into a three- dimensional entity, the two become a whole.

2

The

target

graph

of

the

mark

must

be

coplanar

with

one

or

more

surfaces of the three vertebral entities; and the imprint

operation is limited to the following objects: Arc, Circle,

Straight line, two-dimensional multi- segment line, ellipse,

spline

curve,

surface

area,

body

and

three-dimensional

entity.

15. Purge: Deletes shared edges and those vertices that have

the same surface or curve definition on the edge or vertex.

Remove all redundant edges and vertices, embossed and unused

geometries.

16,

segmentation:???????

You

can

split

a

composite

entity

into

parts. A combination of three-dimensional entity objects

cannot

share

a

common

area

or

volume.

After

a

three- dimensional

entity is partitioned, separate entities retain their layers

and original colors. All nested three- dimensional entity

objects

are

split

into

the

simplest

structure.

Note:

A

Boolean

object with a single volume cannot be divided into separate

three-dimensional entity objects with unconnected bodies,

To split a composite entity into a separate entity

1 Choose Entity Edit split from the Modify menu.

2 Select a three- dimensional entity object.

3 press ENTER to complete the command.

Command line Solidedit

17,

Shell:

Suction

shell

Use

the

specified

thickness

to

create

an empty thin layer. A fixed thin layer thickness can be

specified for all surfaces. The selection surface can be

excluded from the shell. A three-dimensional entity can have

only one shell. AutoCAD creates a new face by shifting an

existing surface out of its original position. Specifies that

the positive value begins to draw the shell from outside the

circumference, and the negative value begins to draw from

within the circumference.

19, check: Verify the three-dimensional entity object is a

valid

ACIS

entity,

this

option

is

independent

of

the

Solidcheck

setting.

Xi, Coloring toolbar: (for two-dimensional does not work)

1,

two- dimensional

wireframe:

Use

lines

and

curves

to

represent

boundaries when displaying objects. Raster and OLE objects,

lines, and line widths are visible

2,

three-dimensional

wireframe:

the

use

of

lines

and

curves

to