Skip to main content

Building Drawing -Using AUTOCAD


BASIC DRAWING COMMANDS FOR AUTOCAD

Measuring Commands
GRID: Displays a grid of dots at a desired spacing on the screen.
Command:  GRID (enter)
On/Off/Tick spacing(x)/Aspect:  (enter value) (enter)
SNAP: Specifies a “round off” interval so that points entered with the mouse can be locked into                          alignment with the grid spacing.
Command:  SNAP (enter)
On/Off/Value/Aspect/Rotate/Style:  (enter value) (enter)
Basic Draw Commands
CIRCLE: Draws circles of any size.
Command:  Circle (enter)
3P/2P/TTR/

:  (pick a center point)
Diameter or :  (Pick a point on the circle)
LINE: Draws straight lines between two points
Command:  LINE (enter)
From Point:  (pick a point using the mouse)
To Point:  (Pick a point using the mouse)
To Point:  (Press return to end the command)
ARC: Draws an arc (any part of a circle or curve) through three known points.
Command:  ARC (enter)
Center/ < Start point > :  (pick the first point on the arc)
Center/End/ < Second point > :  C
Center:  (pick the arc’s center point)
Angle/Length of chord/ :  (pick the arc endpoint)
Display Commands
LIMITS: Sets the size of the drawing paper.  For size “A” drawing paper the limits should be set for                                               10.5 x 8.
Command:  LIMITS (enter)
On/Off/Lower left corner <0.0000> (enter)
Upper right corner: 10.5,8 (enter)
ZOOM: Enlarges or reduces the display of a drawing.
Command:  ZOOM (enter)
All/Center/Dynamic/Extents/Left/Previous/Vmax/Window/:
(pick a point to define one corner of a rectangular viewing window then pick a point to define the second point to define the opposite diagonal corner of the viewing window)
Note:  To return the picture to its original viewing size enter ALL and press the enter key when prompted instead of defining a window.
PAN:           Allows you to move your view point around the drawing without changing the magnification                 factor.
Command:  PAN (enter)
Editing Commands
CHANGE: Alters properties of selected objects
Command:  CHANGE (enter)
Select objects or window or Last (select objects to be changed)
Properties/:  (type P)
Change what property (Color/Elev/LAyer/LType/Thickness)?  (type Layer)
New Layer:  (enter new layer name and press enter)
ERASE: Erases entities from the drawing.
Command:  ERASE (enter)
Select objects or Window or Last: (Select objects to be erased and press enter when finished)
EXTEND: Lengthens a line to end precisely at a boundary edge.
Command:  Extend (enter)
Select boundary edge(s)…
Select Objects  (pick the line which represents the boundary edge which lines will be extended to)
(press enter when finished selecting cutting edges)
/Undo:  (pick the line(s) that need to be trimmed)
Grips
You can edit selected objects by manipulating grips that appear at defining points on the object.  Grips is not a command.  To activate grips simply pick the object.  Small squares will appear at various entity-specific positions.  By selecting an end grip you can stretch the entity to change its size.  By selecting the center grip you can move the entity to a new location.  To remove grips press CTL-C twice.  You can perform the following using grips: Copy, Multiple Copy, Stretch, Move, Rotate, Scale, and Mirror.
Creating Layers
LAYER: Creates named drawing layers and assigns color and linetype properties to those layers.
Command:  LAYER (enter)
A Layer & Linetype Properties dialog box will be displayed.  To add a new layer, pick the New button.  A new layer listing appears, using a default name of Layer1.  the layer name can be changed by highlighting the layer name.  Colors and Linetypes can be assigned to each new layer by picking the color box to assign a color and picking the linetype box to assign a line type.
Standard AutoCAD colors
1 = Red             2 = Yellow          3 = Green  4 = Cyan
5 = Blue             6 = Magenta       7 = White
Standard AutoCAD linetypes
Hidden2 = hidden lines
Center2 = center lines
Phantom2 = phantom or cutting-plane lines
Construction Commands
ARRAY: Makes multiple copies of selected objects in a rectangular or circular pattern
Command:  ARRAY (enter)
Select objects or Window or Last:  (select object to array)
Rectangular or Polar array (R/P) : (P)
Center point of array:  (pick the point around which to form the array)
Angle to fill (+=CCW, -=Cw) <360>:  (enter)
COPY: Draws a copy of selected objects.
Command:  COPY (enter)
Select objects or Window or Last: (select objects to be copied)
Base point or displacement:  (pick a point on the object to be use as a reference point)
Second point of displacement:  (pick a point which represents the new location of the copied
object)
MIRROR: Makes mirror images of existing objects.
Command:  MIRROR (enter)
Select objects or Window or Last: (select objects to be mirrored)
First point of mirror line:  (pick a point on top of the mirror line)
Second point:  (pick a point  on the bottom of the mirror line)
Delete old objects? y or n  (enter)
MOVE: Moves designated entities to another location.
Command:  MOVE (enter)
Select objects or Window or Last: (select objects to move)
Base point or displacement:  (pick a point on the object to be use as a reference point)
Second point of displacement:  (pick a point which represents the new location of the object)
OFFSET: Constructs an entity parallel to another entity at a specified distance.  Offset can be used with  lines, circles, arcs, and polylines.
Command:  OFFSET (enter)
Offset distance or Through :  (enter a distance value)
Select object to offset:  (select object to offset)
Side to offset:  (Pick any point on the side of the object you wish to offset)
FILLET: Changes any corner to a rounded corner.
Command:  FILLET
Polyline/Radius/Angle/Trim/Method/

Comments

Popular posts from this blog

Relation between Modulus of Elasticity and Modulus of Rigidity

Modulus of Elasticity (E)   It is the ratio between Normal stress to Normal strain within the elastic limit. Elastic Modulus E = Normal stress/Normal strain E =  s/e Modulus of Rigidity (G)  It is the ratio between Shear stress to Shear strain within the elastic limit. Rigidity Modulus G = Shear stress/ Shear strain G =    Ƭ / ø   Relation between Modulus of Elasticity and Modulus of Rigidity: Consider a solid cube  PQRS is  subjected to a shearing force F.  Let  Ƭ     be the shear stress produced in the faces PQ and RS due to this shear force. The complementary shear stress consequently produced in the vertical faces PS and RQ is also equal to same and shown in figure as Ƭ   Due to the pure shearing force, the cube is deformed PQRS to PQR'S' . The point   S moved to S' and point R moved to R' as shown in fig.  The shear strain = The angle of distortion  ø                          ø = RR'/ RQ ---(1) Shear strain = Shear stress /Rigidity modulus                

PORTAL METHOD and CANTILEVER METHOD

The behavior of a structure subjected to horizontal forces depends on its height to width ratio. The deformation in low-rise structures, where the height is smaller than its width, is characterized predominantly by shear deformations. In high rise building, where height is several times greater than its lateral dimensions, is dominated by bending action. To analyze the structures subjected to horizontal loading we have two methods. Portal method  and Cantilever method 1. PORTAL METHOD The portal method is an approximate analysis used for analysing building frames subjected to lateral loads such as Wind loads/ seismic forces.  Since shear deformations are dominant in low rise structures, the method makes simplifying assumptions regarding horizontal shear in columns.  Each bay of a structure is treated as a portal frame, and horizontal force is distributed equally among them. Assumptions in portal method   1. The points of inflection are located at the mid-height of each column above th

Shearing Stresses Distribution in Circular Section

Show that the shearing stress developed at the neutral axis of a beam with circular cross section is  τ max = (4/3)(F/πr2). Assume that the shearing stress is uniformly distributed across the neutral axis.  Solution : Let us consider the circular section of a beam as displayed in following figure. We have assumed one layer EF at a distance y1 from the neutral axis of the circular section of the beam Shear stress at a section will be given by following formula as mentioned here Where, F = Shear force (N) τ = Shear stress (N/mm2) A = Area of section, where shear stress is to be determined (mm2) ȳ = Distance of C.G of the area, where shear stress is to be determined, from neutral axis of the beam section (m) Q = A. ȳ = Moment of the whole shaded area about the neutral axis I = Moment of inertia of the given section about the neutral axis (mm4) For circular cross-section, Moment of inertia, I = ПR4/4 b = Width of the given section where shear stress is to be determined. Let us consider on