View Full Version : What is quad ?
mazm 12 December 2006, 10:34 PM Hi guys :)
I saw this word "quad" many times but really i don't know what is quad meaning ?
can anyone explain this to me.
thanx


adh3d
12 December 2006, 10:46 PM
I think the meaning of "quad" in 3d is a polygon with four edges. The 3d models are made by polygons or faces.
newellteapot
12 December 2006, 09:56 AM
Hi!
A quad, short for quadrilateral, is a polygon with four sides (in graphics, the edges) and four vertices.
;)
mazm
12 December 2006, 01:37 PM
monicataddei & adh3d many thanx for your reply :)
blackwood
12 December 2006, 06:00 PM
I don't wish to sound pedantic, but at this point anyone else reading this may still be confused. So...
Polygons or ngons are faces with 4 or more sides.
Quads are faces with 4 sides.
Trianges or tri's are 3 sided faces.
Everything is made up of tri's and the process where quads and other polys get converted into trianges is triangulation. So why make things in quads? Its easiser to work with and important for smoothing operations.
Quads are your friend :)
newellteapot
12 December 2006, 06:29 PM
Not pedantic at all, it's clear, useful and complete, thank you for posting:)
I don't wish to sound pedantic, but at this point anyone else reading this may still be confused. So...
Polygons or ngons are faces with 4 or more sides.
Quads are faces with 4 sides.
Trianges or tri's are 3 sided faces.
Everything is made up of tri's and the process where quads and other polys get converted into trianges is triangulation. So why make things in quads? Its easiser to work with and important for smoothing operations.
Quads are your friend :)
mazm
12 December 2006, 01:11 PM
blackwood :thumbsup: it's always better to add more details in any question in this forum.
thanx
meatycheesyboy
12 December 2006, 12:43 AM
I don't wish to sound pedantic, but at this point anyone else reading this may still be confused. So...
Polygons or ngons are faces with 4 or more sides.
Quads are faces with 4 sides.
Trianges or tri's are 3 sided faces.
Everything is made up of tri's and the process where quads and other polys get converted into trianges is triangulation. So why make things in quads? Its easiser to work with and important for smoothing operations.
Quads are your friend :)
This probably is pedantic but I slightly disagree.
A polygon or an ngon can have any number of edges including 3 or 4. A quad has 4 sides but is also a polygon and is also an ngon; the same holds true for a tri; a tri has 3 sides but is also an ngon or a polygon.
Its like how a square is a rectangle but a rectangle is not a square.
lucavfx
12 December 2006, 11:47 AM
This probably is pedantic but I slightly disagree.
A polygon or an ngon can have any number of edges including 3 or 4. A quad has 4 sides but is also a polygon and is also an ngon; the same holds true for a tri; a tri has 3 sides but is also an ngon or a polygon.
Its like how a square is a rectangle but a rectangle is not a square.
from wikipedia...
A polygon is a closed planar path composed of a finite number of sequential line segments (commonly called edges).
Polygons are named according to the number of sides, combining a greekderived numerical prefix with the suffix gon.
The triangle. quadrilateral and nonagon are exceptions.
For larger numbers, some mathematicians use the numeral itself (6gon).
A variable can even be used, usually ngon.
Polygon names Name Edges
henagon (or monogon) 1
digon 2
triangle (or trigon) 3
quadrilateral (or tetragon) 4
pentagon 5
hexagon 6
heptagon (avoid "septagon" = Latin [sept] + Greek) 7
octagon 8
enneagon (or nonagon) 9
decagon 10
hendecagon (avoid "undecagon" = Latin [un] + Greek) 11
dodecagon (avoid "duodecagon" = Latin [duo] + Greek) 12
tridecagon or triskaidecagon (MathWorld) 13
tetradecagon or tetrakaidecagon (MathWorld) 14
pentadecagon (or quindecagon) or pentakaidecagon 15
hexadecagon or hexakaidecagon 16
heptadecagon or heptakaidecagon 17
octadecagon or octakaidecagon 18
enneadecagon or enneakaidecagon or nonadecagon 19
icosagon 20
icosihenagon 21
triacontagon 30
tetracontagon 40
pentacontagon 50
hexacontagon (MathWorld) 60
heptacontagon 70
octacontagon 80
enneacontagon 90
hectagon (also hectogon) (avoid "centagon" = Latin [cent] + Greek) 100
chiliagon 1000
myriagon 10,000
decemyriagon 100,000
hecatommyriagon (or hekatommyriagon) 1,000,000
So to wrap it up
ngons 1 or more edges
polygons 1 or more edges
triangles 3 edges
quads 4 edges
Hope it helps :)
Luca
Shonner
12 December 2006, 05:09 AM
Quad is a nickname for a 4sided polygon.
newellteapot
12 December 2006, 09:48 AM
This post by Lucavfx should be a sticky! :)
from wikipedia...
A polygon is a closed planar path composed of a finite number of sequential line segments (commonly called edges).
Polygons are named according to the number of sides, combining a greekderived numerical prefix with the suffix gon.
The triangle. quadrilateral and nonagon are exceptions.
For larger numbers, some mathematicians use the numeral itself (6gon).
A variable can even be used, usually ngon.
Polygon names Name Edges
henagon (or monogon) 1
digon 2
triangle (or trigon) 3
quadrilateral (or tetragon) 4
pentagon 5
hexagon 6
heptagon (avoid "septagon" = Latin [sept] + Greek) 7
octagon 8
enneagon (or nonagon) 9
decagon 10
hendecagon (avoid "undecagon" = Latin [un] + Greek) 11
dodecagon (avoid "duodecagon" = Latin [duo] + Greek) 12
tridecagon or triskaidecagon (MathWorld) 13
tetradecagon or tetrakaidecagon (MathWorld) 14
pentadecagon (or quindecagon) or pentakaidecagon 15
hexadecagon or hexakaidecagon 16
heptadecagon or heptakaidecagon 17
octadecagon or octakaidecagon 18
enneadecagon or enneakaidecagon or nonadecagon 19
icosagon 20
icosihenagon 21
triacontagon 30
tetracontagon 40
pentacontagon 50
hexacontagon (MathWorld) 60
heptacontagon 70
octacontagon 80
enneacontagon 90
hectagon (also hectogon) (avoid "centagon" = Latin [cent] + Greek) 100
chiliagon 1000
myriagon 10,000
decemyriagon 100,000
hecatommyriagon (or hekatommyriagon) 1,000,000
So to wrap it up
ngons 1 or more edges
polygons 1 or more edges
triangles 3 edges
quads 4 edges
Hope it helps :)
Luca
jtaddei
12 December 2006, 07:01 PM
hahah luca, that should come with a pronounciation guide. Sweet find.
Snikske
12 December 2006, 05:36 PM
a quad isn't always planar i think. Only tri's are always planar.
A quad consist of two tri's, with one hidden edge.
kirigoi
01 January 2007, 01:17 PM
Right you are Snikshe, you can fix rendering errors from nonplanar quads by converting them to tris; tris by definition are always planar.
CGTalk Moderation
01 January 2007, 01:17 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.