Should there be a limit to how many in game models there is for a 3d MMORPG?

Question

I was considering building a character creator/customizer program that would enable a player to create their own 3d model based off of a series of preset body parts. i.e. A player could choose to add the legs of a horse, the body of a man, wings of a falcon and the head of a snake. From there the player can then customize each body part by tweaking sliders responsible for length, thickness, color, position, etc.

Ultimately this will give players the ability to customize their characters with infinite degrees of freedom (not like preset customizations we see in some MMORPGs i.e. 8 hair cuts, 10 faces, 8 body types, etc.). So as you can imagine this would most likely lead to ever player having a different character.

Would having thousands upon thousands of separate 3d character models some how slow the game down?

I consider that it would not because the most characters that would be rendered in the game I am working on would be 25 to 50 if that.

Answer 1

City of Heroes and Champions Online already do the things you are talking about.

Yes, it adversely affects performance in many areas - notably rendering and animation - as well as the art team (financial) budget. If you're trying to do this, you should make sure you have good performance budgeting tools throughout the entire art process, and good test cases.

Answer 2

You don't need to generate unique models in each case. Instead you can render a character as several models, one for each of the interchangeable parts you mention, with the tweakable aspects being applied to animation bones, or to shaders, etc.

However, to answer your question more generally, it is almost always quicker to render the same model twice than to render 2 separate models. Obviously this is mitigated if you are only rendering a subset of those in a given time frame because the other ones effectively do not exist at that stage. But rendering 25 different models will almost always be slower than rendering 3 or 4 each duplicated 6 or 7 times over.

But speed is relative - when does 'slower' become 'too slow'? If your characters are quite simple (ie. low number of polygons and small textures), then 50 on-screen at once is not a big deal. On the other hand, if they are complex, then even just 25 at once may be too much on some cards. It would be a shame to cancel a good feature because of performance concerns, so you need to know which end of the scale you would be at.

Luckily this is something you can test quite easily, by generating sample geometry of the sort of complexity you expect to use (which can be any simple object tessellated appropriately), and performing some test rendering to observe the real-world performance.

Interestingly, although you mention rendering as a bottleneck, potentially a worse problem is the networking aspect. Most MMOs store the majority of renderable assets on the client side and deploy them as part of the original install or the patching procedure. In your case, this would be impractical due to the number of permutations, so you'd have to stream them down during play. But this in turn means you can't easily render a character until all this data is on the client, which may be a problem when entering a busy area quickly (eg. teleporting or spawning in town). Again, this problem is reduced a bit if you just send a list of pre-existing model-parts that a character uses character instead of having to send a full model for each one.

Answer 3

I don't think so. Oblivion and Sims 3 both featured more models than you can even imagine.