3D Graphical Projection

5/26/2018 3D Graphical Projection

1/7


2/7

plane). It is the projection type of choice for working drawings.

i. Axonometric projection

Within parallel projection there is a

subcategory known as Pictorials . Pictorials

show an image of an object as viewed from a

skew direction in order to reveal all three

directions (axes) of space in one picture.

Parallel projection pictorial instrument

drawings are often used to approximate

graphical perspective projections, but there

is attendant distortion in the approximation.

Because pictorial projections inherently have

this distortion, in the instrument drawing of

pictorials, great liberties may then be taken

for economy of effort and best effect. Parallel

projection pictorials rely on the technique of

axonometric projection ("to measure along

axes").

ii. Isometric projection

In isometric pictorials, the direction of viewing is such that the three axes of space

appear equally foreshortened, of which the displayed angles among them and alsothe scale of foreshortening are universally known.

All isometric drawings are made with the 30-60 triangle, and most of them are done

in angular "perspective" where the two sides make an angle of 120 degrees with

each other and 30 degrees with the horizontal. In isometrics all s ides that are parallel

stay parallel and will not vanish to a vanishing point if prolonged. There are neither

vanishing points nor foreshortening in isometric drawing. The difference between true

B. Pictorials
http://2.bp.blogspot.com/-yXvA6HJ64V0/TwDddm-IonI/AAAAAAAAAGs/YQGkFKPJ3Xw/s1600/axonometric-projection.pnghttp://1.bp.blogspot.com/-32GKvQO41hY/TwDk5MRCH4I/AAAAAAAAAJE/LWH59V3ByCc/s1600/_%25D8%25A7%25D9%258A%25D8%25B3%25D9%2588%25D9%2585%25D8%25AA%25D8%25B1%25D9%2583.jpg


3/7

perspective and isometric drawing is shown in the diagram 34, where A is the

perspective of a block and B is the isometric drawing of it. It is also shown clearly in

Figure 35 where C is the perspective and D the isometric drawing of the same thing.

The three vertical edges a, b, and c of the block are called isometric axes, and all

lines parallel to these edges are called isometric lines. Measurements can be madeon the main isometric axis (b) only, for all other lines are inaccurate because they

are not in true perspective.

Isometric drawing

Is made up of a series of parallel vertical lines and parallel 30 degree

lines
http://4.bp.blogspot.com/--lHpUN7a_Jg/TwDdvmQbp0I/AAAAAAAAAG4/grwXQXucjPw/s1600/mechanicaldrawingtips20_clip_image002.jpghttp://4.bp.blogspot.com/-qkeUiZQk0SM/TwDc7SDiQFI/AAAAAAAAAGg/nyI7v1GG__4/s1600/isometric-projection.png


4/7

It is usually drawn out with the aid of a 30/60 degree set square.

Isometric is 30 degrees only

Sometimes Isometric grid paper is used to aid the drawing

NOTE: THERE ARE NO HORIZONTAL LINES

iii. Oblique

projection

In oblique projections the

parallel projection rays are not

perpendicular to the viewing

plane as with orthographic

projection, but strike the

projection plane at an angle

other than ninety degrees. In

both orthographic and oblique

projection, parallel lines in

space appear parallel on the

projected image. Because of

its simplicity, obliqueprojectionis used exclusively

for pictorial purposes rather

than for formal, working drawings. In an oblique pictorial drawing, the displayed

angles among the axes as well as the foreshortening factors (scale) are arbitrary.

The distortion created thereby is usually attenuated by aligning one plane of the

imaged object to be parallel with the plane of projection thereby creating a true

click on Image
http://1.bp.blogspot.com/-enT-uc0xmFI/TwDev1sy_6I/AAAAAAAAAHQ/49GYF7s4CKI/s1600/iso-1.gifhttp://1.bp.blogspot.com/-OOKDUzZ-yhY/TwDfDUyaC6I/AAAAAAAAAHo/3i3fi35SSDQ/s1600/isomgrid.gifhttp://3.bp.blogspot.com/-UHoItdIm0NY/TwDe-VtX5YI/AAAAAAAAAHc/XP2OjxU8c7Q/s1600/set-square.gifhttp://1.bp.blogspot.com/-pXvHO_iT4NU/TwDd-WhtuJI/AAAAAAAAAHE/ngbCcoGOO6s/s1600/oblique-projection.png


5/7

shape, full-size image of the chosen plane.

Method of Drawing

Oblique projection is a method of drawing objects in 3 dimensions. It is

quite a simple technique compared to isometric or even perspective

drawing. However, to draw accurately in oblique projection traditional

drawing equipment is needed

The technique for drawing a cube in oblique projection is outlined

below, stage by stage. To draw it correctly in oblique projection three

main rules must be followed:

1.Draw the front or side view of the object.

2.All measurements drawn backwards are half the original

measurement.

3.45 degrees is the angle for all lines drawn backwards

A.Draw the front view. Remember to use a T-square and 45

degree set square.

click on Image

click on Image
http://1.bp.blogspot.com/-8Pjl-RhEIqI/TwDhav9WjXI/AAAAAAAAAIU/HyfW_I5ZOaA/s1600/obliq3.gifhttp://4.bp.blogspot.com/-fKkKZYHX984/TwDg_v0MUeI/AAAAAAAAAH0/7fqYkLaDMfY/s1600/obliq1.gifhttp://3.bp.blogspot.com/-xEPKTeGUtIg/TwDhBVOdXGI/AAAAAAAAAH8/_MDtiIqSifk/s1600/obl2.gif


6/7

Posted by Ms.Amal Aljohani at 1:58 AM

B. Draw 45 degree lines from each corner of the square. The

distance of any lines drawn back at 45 degrees should be halved. For

example, a cube may have sides of 100mm but they must be drawn

50mm in length. This should mean that the cube will look more realistic

and in proportion

C.Draw 45 degree lines from each corner of the square. Thedistance of any lines drawn back at 45 degrees should be halved. For

example, a cube may have sides of 100mm but they must be drawn

50mm in length. This should mean that the cube will look more realistic

and in proportion.

click on Image

click on Image

Recommend this on Google

No comments:

Post a Comment
http://www.blogger.com/share-post.g?blogID=5532611590342837140&postID=4793407982395166274&target=pinteresthttp://www.blogger.com/share-post.g?blogID=5532611590342837140&postID=4793407982395166274&target=facebookhttp://www.blogger.com/share-post.g?blogID=5532611590342837140&postID=4793407982395166274&target=twitterhttp://www.blogger.com/share-post.g?blogID=5532611590342837140&postID=4793407982395166274&target=bloghttp://www.blogger.com/share-post.g?blogID=5532611590342837140&postID=4793407982395166274&target=emailhttp://4.bp.blogspot.com/-L1a73vCTj58/TwDiDOxuTWI/AAAAAAAAAI4/Rx44Ltfwy9U/s1600/obliq5.gifhttp://2.bp.blogspot.com/-jwEfMrqIDkA/TwDhwPLTYCI/AAAAAAAAAIs/g_SM9-dDGz8/s1600/obliq4.gifhttp://int331.blogspot.com.au/2012/01/graphical-projection.html


7/7

Older PostHome

Subscribe to: Post Comments (Atom)

Enter your comment...

Comment as: Google Accou

Publish

Preview

Share this on Facebook

Tweet this

View stats

(NEW) Appointment gadget >>

Share it

Follow by Email

Email address... Submit

Simple template. Template images by mariusFM77. Powered by Blogger.
http://www.blogger.com/http://www.istockphoto.com/googleimages.php?id=4940465&platform=blogger&langregion=enhttp://www.appointron.com/appointron-for-blogger?utm_source=shareit&utm_medium=text_ad&utm_content=textad&utm_campaign=shareithttp://void%280%29/http://twitter.com/home?status=Check%20out%20this%20site:%20http%3A//int331.blogspot.com.au/2012/01/graphical-projection.htmlhttp://twitter.com/home?status=Check%20out%20this%20site:%20http%3A//int331.blogspot.com.au/2012/01/graphical-projection.htmlhttp://www.facebook.com/share.php?u=http%3A//int331.blogspot.com.au/2012/01/graphical-projection.html&t=Check%20out%20this%20sitehttp://www.facebook.com/share.php?u=http%3A//int331.blogspot.com.au/2012/01/graphical-projection.html&t=Check%20out%20this%20sitehttp://int331.blogspot.com/feeds/4793407982395166274/comments/defaulthttp://int331.blogspot.com.au/http://int331.blogspot.com.au/2011/12/lettering.html

3D Graphical Projection

Documents

Transcript of 3D Graphical Projection