Machine Drawing

424 Machine Drawing

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d:\N-Design\Des21-1.pm5

B

A

Change point

Original value

Change radius

Initial position

Command: ELEV

New current elevation<0>: 10 enter

New current thickness<20>: 40 enter

Now, draw a rectangle using RECTANG command and use view points suitable to create

3D shapes of the objects, eg., a cylinder at 0 elevation having thickness 20 units and a rectangular

prism at 10 units of elevation and 40 units thickness.

21.20 CHANGE PROP

Features: 1. Changes length, colour or type of a line,

2. Changes the layer in which the entity is

drawn,

3. Changes the elevation of component, and

4. Both properties and change point options are

available.

Command: CHANGE (Fig. 21.25)

Select objects: pick the objects

Select objects: enter to stop the selection process

Properties:

By choosing properties option: P— enter

Change what property? (Colour/Elev/Layer/L type/

Its scale/Thickness):

By choosing,

Colour — New colour by layer: choose any colour

Elev — the elevation of the object chosen can be changed

Layer — Layer of the object can be changed

Thickness — New thickness values may be assigned

L type — line type of the objects chosen can be changed

By choosing point option:

The end point of a line or size of the circle can be changed.

21.21 EXTRUSION

Features: A plane surface is extruded or converted to 3D drawing by applying thickness to it,

eg., circle growing into a cylinder or a polygon grows as a prism, etc. Straight/parallel extrusions

or extrusions with taper are also possible.

NOTE: A 3D drawing may also be created by choosing the command.

ELEV: and choosing a suitable view point

The response of the computer to this command is given below:

Command: EXTRUDE (Fig. 21.26)

Select objects: make selection

Select objects: enter to stop the process of selection

Path / height of extrusion <0>: 15 choose a value

Fig. 21.25