Unity and Ios Rig specs?

kream

Hey guys,

Just had some quick questions for anyone who's had experience with the Ios. We are starting the process of porting our title over, but I was wondering about bone counts for rigs. I am seeing that Unity, and a few people online "recommend" around 30 bones. Currently our title has characters ranging from 80+ on up. I know this is too big, but what are people getting away with on these devices. We are looking at an Ipad and possibly an Iphone4 release. Any help/info would be greatly appreciated. Thanks in advance!

Mark Dygert

Hands are probably the fastest way to cull a lot of bones quickly.

There are normally 16-20 bones per hand in the rigs I make, that's a huge savings if you can bring that number down. You can merge a few fingers together and control them with one chain of bones instead of separate chains. Removing twist bones and spine bones would probably be next.

If you're using biped it would be very easy to transfer existing animation from the dense rig to the lower using motion mixer.

kream

Yeah, that's kinda the route I went so far. Took out the fingers, a spine bone, all twists, and most face stuff. I ended up keeping eye lids, and a sort of mouth flap as well. I got the rig down to 25-30ish. And yeah, we're using a biped for that specific reason.

Mark Dygert

Ahh smart move using biped.

Depending on how the face animates you might be able to get away with using only one set of bones for both pairs of eyelids? You would lose independent eyelid animation but you would still be able to blink.

If all the eyelids are doing is blinking, you might be able to handle that with a simple animated material. If you edit the mip-maps for the material you might be able to just use the same material and cycle through the mip map levels.

kream

I've been tinkering with the rig a bit. The eyes don't do much, so the 1 bone would be fine. Some of the character we have, have a lot of "extra" bones for hair, chains, and other decorative pieces. So I'm really just trying to figure out where to optimize, and where to actually cut stuff from the models, and figure out if the ios has a hard line cap.

poopipe

bones are processed in groups of 12 on our engine, I think this applies across the board (pretty sure it applies to unity at least) ie. if you have 25 then you might as well have 36.

a big performance hit ( for us at least) is messy skinning, minimizing the number of bones influencing a triangle ( that's the total number affecting all 3 of its verts) makes a big difference to what gets shoved through the various tiny little pipes in an iphone.

osman

Might also be useful to know how many of these characters you're planning on having on screen?

kream

We are looking at probably 3 at a time, but potentially up to 6. Each character consists of about 3500 tris, the environment is fairly simple as well. From what I'm gathering in and around the net, there doesn't really seem to be a hard capped number of only x amount of bones on a skinned mesh (saw mention of a 75 bone limit on the UDK forum, but not sure if thats ios specific, or UDK).

I will be playing with it to see what brings about the best results.