Game engines in relation to poly count?

mdeforge

I was wondering if I could get a clear explanation of how game engine's effect polycount. What's to say I can't take Unreal 2003 and plop a 15k GOW character model into it? What is it that caps the polycount on these older engines? Speed? Overhead? Can't manage the data effectively? Obviously C++ is faster than BASIC, so I can see how computer language effects engine speed, but why else do engine's age exactly?

dextor

na not a solution but another silly doubt here,
wat's the basic configuration for UE3
can anybody tell me?"

jocose

I think the issue of polycount is far less important that texture resolution, shaders, draw calls, ect

Polycount is one of the simplest things a game engine has to do. It's all just basic math so if your computer is fast enough to handle all the points then its going to render fine.

There are limits in game engines that define how big meshes can be, but these limits are usually just put in place because some kind of limit has to exist and are often times arbitrary.

I don't know any specific limits off the top of my head, but really I think it's more a question of your target system(s) power than what engine you are using when it comes to a models polycount.

Ruz

I thought yu meant how they affect polycount the forum:)

blankslatejoe

Jocose's right, polycount doesn't seem to be as crucial as texture budgets, fill rate (shader complexity), draw calls/batch calls, and etc.

polycount does still come into affect though--having over 32,000 verts can sometimes be a problem (I think it has something to do with storing the verts in a 16bit versus 8 bit). Older engines may assume a mesh is going to be under that and may import the mesh all wonky if at all, connecting edges to the wrong verts and screwing up vertex order and what have you.

Also, having an object take up too much 'space' in the world can sometimes be problematic, since towards the extremities of an engine's limits you can run into precision errors (collision will act funny, things may render weird, etc)

And just because you CAN import a 30k+ mesh doesn't mean you should ... Even current gen engines can crawl when it gets to a million or two verts. If that were ALL characters at 30k then thats only a few dozen on screen..with nothing to account for environments, FX, UI, or etc.

Anyway, I dunno if that answers any questions. There's no quick 'clear answer' for a lot of this stuff

Firebert

Ruz wrote: »

I thought yu meant how they affect polycount the forum:)

dammit! you beat me to it!

Mark Dygert

Firebert wrote: »

Ruz wrote: »

I thought you meant how they affect polycount the forum:)

dammit! you beat me to it!

Probably because someone's space bar is broken... heh

Vailias

A lot of it varies per engine and how the model data format is handled/implemented. UT2k3 doesn't seem to have a restrictive upper limit if it does have a limit at all. There have been character with 15000k plus tris created by players that run just fine in the engine.

Old torque had coded limits of no more than 10000 triangles per continuous mesh and no textures larger than 512 square.


An engine's abilities to put polys on screen comes down to what else has been said here, draw calls, fill rate, etc.

A lot of what effects older engines is scene management and data handling issues. Occlusion algorithms, batching, texture memory management, etc.. all these affect an engine's performance.

Directly relating to per model.. or rather on screen polycount are the things related to occlusion/culling and batching/draw calls.
Drawing takes a large amount of time, so deciding to not draw things saves time in the long run, ie if they are too far away or off frame, or behind something else entirely.
Anyway the specifics of these and their particular efficiency varries from engine to engine, and newer engines are more likely to have newer and more refined techniques, and of course some techniques utilize new hardware.

mdeforge

Thanks for the responses everyone. Very good info I knew it had to do with a combination of these things, but when someone asked me the question of "How many poly's can such and such engine handle" I wasn't able to articulate why he was asking the wrong question. Thanks.

Haha, sorry, Poly count* :poly121:

MoP

I fixed the title and moved the thread to Technical Talk.