Why did GPUs abandon quads in favour of triangles (and will quads make a comeback?) *spawn

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It's cleaner to look at and work with. The exporter will then convert everything into triangles.
 
Lousily. GPUs work in triangles. You'd still have to subdivide into triangles at some point to rasterise them. Only the Saturn console rendered quads. If you're going to turn quads into trisets, may as well do it in the export and save the realtime processing.
 
If you use the tesselator to do quads, you would almost get it for free in comparison to triangle tesselation.

If tesselation becomes even more used in future even on settings of games for minimum requirements then quads could replace triangles, right? At least on mobile devices...

With quads you have 1/5 less polygons to store and process and you have 1/2 less draw calls for textures for same result compared to triangle rendering?
 
I think one of the reasons (this is just a guess from my limited experience with ZBrush) why we stayed with triangles was that 3D games started with very very low polygon budgets. Quads are a little less flexible when dealing with very low polygon objects. You would require to use more and smaller quads in order to make up for the lack of flexibility and display a little more complexity in the geometry. It would eat up your polygon budget that way faster unless you wanted to make your models show less polygons. That would explain why in most cases game ports from PS to the Saturn resulted to models with less polygons on the latter.

For reference imagine having just one quad. You cant do much with it.

Now imagine that quad and the same size divided into two triangles (draw a diagonal line from one edge to the other). Vertice points are the same but now that area offers more flexibility.

Now if you have hundreds of thousands or millions of polygons on your model, quads arent a problem anymore when modeling (edit: but I am unsure if that would be efficient hardware wise. I dont know if more quads/vertices are required in order to display the same result compared to using triangles when dealing with significantly larger polygon budgets)

Games still use some low polygon models for "unimportant"/small objects or objects farther into the distance so it makes sense.
 
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I think one of the reasons (this is just a guess from my limited experience with ZBrush) why we stayed with triangles was that 3D games started with very very low polygon budgets. Quads are a little less flexible when dealing with very low polygon objects. You would require to use more and smaller quads in order to make up for the lack of flexibility and display a little more complexity in the geometry. It would eat up your polygon budget that way.

For reference imagine having just one quad. You cant do much with it.

Now imagine that quad and the same size divided into two triangles (draw a diagonal line from one edge to the other). Vertice points are the same but now that area offers more flexibility.

Now if you have hundreds of thousands or millions of polygons on your model, quads arent a problem anymore.

Games still use some low polygon models for "unimportant"/small objects or objects farther into the distance so it makes sense.
They do, but haven't seen any low poly tree that could not be made of quads...
 
It is possible to make anything out of quads instead of triangles. Besides ZBrush sculpting that Laa-Yosh was speaking of uses quads as a base.
My question is though how many would you need compared to the ones made out of triangles in order to achieve the same result in a game where you have limited polygon budget?
 
It is possible to make anything out of quads instead of triangles. Besides ZBrush sculpting that Laa-Yosh was speaking of uses quads as a base.
My question is though how many would you need compared to the ones made out of triangles in order to achieve the same result in a game where you have limited polygon budget?
Right. It's trivially obvious that any object that can be made out of tris can also be made out of quads; after all, if you glue two of a quad's vertices together, you wind up with a tri. There's a question of efficiency, though.
 
It is possible to make anything out of quads instead of triangles. Besides ZBrush sculpting that Laa-Yosh was speaking of uses quads as a base.
My question is though how many would you need compared to the ones made out of triangles in order to achieve the same result in a game where you have limited polygon budget?
A sprite/2d tree needs 5 polygons and 2 texture calls/draws/applies to apply a texture to each triangle versus 4 polygons and half as much for textures...

A octagon in triangles needs 13 versus in quads 10 polygons... Circle 48 in triangles or less than 40 with quad...
 
A sprite/2d tree needs 5 polygons and 2 texture calls/draws/applies to apply a texture to each triangle versus 4 polygons and half as much for textures...
?

Why does a sprite tree need 5 polygons? And what are you referring to as a "texture call/draw/apply"?

A octagon in triangles needs 13 versus in quads 10 polygons...
???

It takes six triangles to form an octagon, or 3 quads.

Circle 48 in triangles or less than 40 with quad...
Okay, now I'm definitely confused. It's not possible to form a circle from a finite number of triangles. We approximate circles with small numbers of polygons, but there's hardly a standard on just how good the approximation needs to be.
 
If you are dealing with game 3D models there is a possible loss on geometry by going with quads because you reduce the diagonal breaking points of the polygons. There wont be a difference of course if all quad areas are flat with or without tris of course. In that case it sounds like it would be efficient . But I am no technical expert so I dont know

Anyhow I just did a search and found these explanations

http://stackoverflow.com/questions/6100528/why-are-there-always-triangles-used-in-a-3d-engine
http://gamedev.stackexchange.com/qu...to-triangles-compared-to-keeping-it-as-four-s

edit: Well based on these links tris appear to be more efficient
 
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?

Why does a sprite tree need 5 polygons?
In 3D polygonical games
And what are you referring to as a "texture call/draw/apply"?
Applying texture to objects, 2 triangles versus 1 quad... If you have a simple box then you have 12 triangles or 6 quads...
???

It takes six triangles to form an octagon, or 3 quads.
Yes, now count how many polygons/lines does it need and I already did it....

Okay, now I'm definitely confused. It's not possible to form a circle from a finite number of triangles. We approximate circles with small numbers of polygons, but there's hardly a standard on just how good the approximation needs to be.
A well rounded circle has 24 triangles to avoid being too edgy...

MOD advice: Type {quote} and {/quote} tags around the parts you're quoting replacing { with [. Don't type bolded inside a quote.
 
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Nesh is right about the legacy of old game assets. In the days of Quake 3 I think it was around 800 triangles per character and the modeler had to be pretty clever to make the most out of that, especially in getting reasonably curved silhouettes from every possible angle. It's kinda hard to find good images nowadays, but Paul Steed* had an ongoing 3D character column on loonygames where he showed a lot of actual assets and explained processes.
doom236.jpg

You can see here how the mesh was carefully optimized down as much as possible while maintaining a more or less curved silhouette. The usual method was to start with a quad mesh like a very simple cylinder, push and pull vertices to get a good shape, and then decimate it down a lot.
You can also see that the low number of polygons helps to keep the wireframe display clean and how you could assign skin weights down to the specific vertex level. Today with an 50-100k mesh the display gets messy and unreadable, and most of the skin weighting is done using brush based painting tools. Here, a mostly quad mesh works much better. But modelers still use triangles here and there to terminate or add detail.

(by the way, that's the arm of the Doom guy character from Q3 :D)

* I've basically learned low poly modeling from Steed's articles, it was an invaluable resource. May he rest in peace...
 
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Well anyone with a technical know how who can jump in for Blastingthosejets' post? It is not my territory :p
 
Right. It's trivially obvious that any object that can be made out of tris can also be made out of quads; after all, if you glue two of a quad's vertices together, you wind up with a tri. There's a question of efficiency, though.

Quad mesh topology, basically the edge layout, is very different, it's a lot harder to locally increase detail and keep the mesh 'tidy'.
I'm pretty much OCD about this, don't get me started ;)
 
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