Faces vs Polys vs Tris
Yes, it's me again, with another question. What is the difference between faces, polys, and tris? I understand polys are polygons, and tris are triangles, but what is the difference between them all? how do i calculate one from the other? i've searched here and on the web, but i'm just not getting the search down right, because i still can't find a straight answer about any of them.
Replies
Polygons and faces are for simplicity sake the same thing. If your model is 4000 polygons, then it's 4000 faces.
I think that's the correct way to put it.
The reason your count doubles is probably because it was triangulated when you exported (turned from quads to triangles), or for whatever reason it is telling you the number of triangles and not quads. Because one quad = 2 triangles (cut it diagonally, you get two triangles).
poly = n vertices (where n can be any natural number equel or higher than 3 {3, 4, 5, ...}
face = poly
so lets say it this way: you always have polys, the triangle is just a special case
game related, you talk always about tris, even if you say polygone
After a test found that if you work in edit-poly and export a file then re-import that file the count increases as the object is triangulated automatically.
There seems to be no user intervention required when preparing an object for importation as the engine will triangulate the model for you.
Poly - A loose term for a surface area confined by edges and vertices. Every even sided area is a poly except for ngons and tri's.
Face - Is the same as poly except it is an even looser term which includes ngons and three sided area's (tri's).
Tri - Is most commonly referred to in game engine conversion of a model but can also mean a problem area on a model that won't divide properly.
I don't think that Polygons just means even-sided.. er.. Polygons.
This site seems to explain it pretty well : http://en.wikipedia.org/wiki/Polygon#Naming_polygons
Two of those examples didn't really make sense to 3d or me at all - http://en.wikipedia.org/wiki/Henagon and http://en.wikipedia.org/wiki/Digon
Just wondering are you sure this is directly related to 3d or just purely mathematics? I know the two subjects are heavily linked but maybe terminology has got lost or confused along the way :poly108:
Well that's because in Max the polygon counter counts polygons instead of triangles by default. Polygons are two or more triangles. Depending on the version of 3ds max you use you would either have to go to viewport configuration under statistics to set max to show the triangle count or go your shortcuts and switch the 7 shortcut from polygon counter to triangle counter.
As far as the face vs polygon lingo it just that semantics. A clear example of this is how different software refer to the same thing with a different term, some call vertices, vertex, vert, or point. The same is true for polygons, some call them faces. On of the unique features that Max had for countless years was the ability to select triangles easily instead of quads. If you want to select just one triangle in another application you have to cut the face into tris.
Alex
That particular site is just a general geometry-centric description, there may be better sites that explain the terminology. But one can already see that "tris" is derived from "triangles" and "quads" from "quadriliterals". From what i understand, everything "past" a Quad is usually just binned under "N-Gons".
The industry predominantly uses Max, Maya, and XSI, they all agree with what Vig posted. Hell, even Lightwave does as far as I can recall.
jackbanditdude01 Ahh I should have also said that faces are calculated as individual surface area's so if you triangulate a quad poly it will become two faces.
For Max users this was bs introduced with editable poly back in version 4, however other software felt it was important to count triangles, verts, edges, ngons and you guessed it polygons. WTF isn't polygons the same shit as triangles. In that context it refers to quads but the assholes decided to call it either face or polygons which is just freaking confusing. They should have called it quads, but I guess Autodeks would sue them or they need to be different. Why cause they feel the need to be original, in other words it's just semantics. I wish they were as anal about making the damn software user friendly and consistent instead of changing every freaking little term to say they are special...
I don't use Blender so I don't' know what they decided to call two triangles. I'm sure they made it sound special.
Well I hope that makes sense.
Alex
Thanks everyone for the help.
P.S. - For everyone who keeps badmouthing Blender... Blender, SoftImage XSI, Maya, 3ds Max, and all the other little programs out there, everyone has preferences, and from spending a little over a month working on Blender, Maya, and Max, I'd have to say one is no better than the other, for any program. Depending on how much effort was put into design and plugins and script, any one can do exactly what the other can, just in a much different way. Experience brings ease, not the program itself.
Alex
There is no discussion here. Only an inconsistency in terminology and functionality betweem separate applications that you seem unable to comprehend. In the context of games and any other realtime application...triangles are what count, and what is counted. I just so happens that a triangle falls under the definition of a face, and a polygon. Here, see for yourself:
polygon : a closed plane figure bounded by straight lines
triangle : a polygon having three sides
face : any of the plane surfaces that bound a geometric solid
It is unfortunate that some DCC tools, that were seemingly developed in 3rd world countries, have managed to mislead you, like so many others, to believe otherwise.
Now for a math lesson. Take one quadrilateral, or quad. That's a new word, Quad. It means four. It is one 4-sided polygon. Divide that in half from one point to another. You have now 2 triangles. One 4-sided polygon EQUALS two 3-sided polygon. 1 to 2. That's double. You like milkshakes?
It may be that Blender triangulates OBJs during export by default. That is often encouraged when exporting OBJs to prevent errors when importing to other applications. It may be that Max reads Blender's OBJ file different, and rebuilds its faces. Max has poor OBJ support that will hopefully be fixed with version 2009, as they have claimed. What happens between Blender and Max makes no difference, because most people here aren't dumb enough to have that workflow. Their preference isn't that of torture. For example: XSI provides info on triangles, quads, N-gons, points, etc. all on one stat window. It's convenient.
And lastly, since you have stated that you are only one month "into this", you have little room to be claiming anything about "intuitive" and "preference" and "experience". These programs are, in fact, only tools, and it is the artists which create the results. But to make these statements, you need more knowledge of what these tools can do for you as an artist. And that takes years of practice using many of the tools available. This is a forum frequented by many who have. And they have found that some programs, over all aspects of design, bring much more ease to their methods. Of these, Blender is rarely mentioned. But it is free, and has all the features a nuclear physicist would love...so high five.
I should have elaborated...
The dotted lines are hidden edges of triangles. Polygons can be made up of many triangles which is what makes them unreliable when counting. Think of a polygon as a shoebox, normally you put two shoes (tris) in there but you can pack in more if you want, so counting shoeboxes to find out how many shoes you have could give you an incorrect count. The best way to find out how many shoes you have, is to count shoes.
Blender's .obj export script doubles the verticies dued. ;p
export and then load it back in blender and you'll see it doubled
i think
Horrible 1st post hmm
I usually do a quick ctrl-t riangulate on the whole mesh and look at the facecount, and then redo to go back to my model.
the blender obj exporter only splits faces and doubles vertices if there's an edgesplit involved, which should in a proper scenario convert to smoothinggroups instead, but I guess since it's named edgesplit...
the in the startingpost is quadmesh being exported into an obj, auto-triangulated, and imported in as a trianglemesh, with the correct count in blenders "face" count.