What to aim for in a model to rig for a game?


I have questions spinning in my head that I can’t quite find answers to…

I’m interested in making a model to rig and animate and make it work in Unreal 4. I have been meddling with rigging and weightpainting before, so I have a pretty good idea what I’m doing as far as that goes. But I’ve never thought about how to make my model appropriate for use in a game (and make it look good)

  1. What is an ‘ideal’ polycount for use in rigging? (not aimed at performance, rather aimed at workflow and how good the end result will look in game)

Currently my model has 10-12 sides around the legs, and 8 sides around the arms. And the knee, elbow and finger joints have 2 loops in the inside of the joints, and an extra 2 half loops extruded on the outside. I think the model so far would prove to be quite easy to rig and make it deform properly, as it doesn’t have a huge amount of vertexes to work with. And normally I would just slap on a subsurf modifier to make it all look smooth and I’d be satisfied with that.

But I figure a subsurf isn’t gonna translate to the unreal engine at all, so that won’t work.

To answer my own question I wanted to see an example of a character model, so after spending 1,5 hours to find a character model of Street Fighter V, which is made in Unreal 4 engine, my findings were peculiar. I won’t share the model 'cause I’d probably break some rules if I did, but to give you an idea, it has about 30 sides around the leg, 26 around the arm and I don’t even want to know how many loops they had to deal with around the joints.
So this leads me to question #2

  1. How do people go about rigging a high resolution(polycount) character?

Is it exactly the same as rigging a low resolution model? Or do they use deformer meshes and such to animate the high res, and then just bake and export the animations to the game (if that’s even possible)? As for possibilities, that leads to my last question (for now)…

  1. What kind of animation tools are able to be exported through .fbx into Unreal?

So far I know that obviously the bones and their weights on the vertexes can be exported. IK setups work and I’ve also seen a clip of a stretching bone working in Unreal, though I’m not sure if that was a ‘stretch’ bone constraint that was exported succesfully or if it was an IK bone setup with the stretching turned on. I also know about Shape keys (called something with morphing in Unreal 4) working.
So are there any other handy tools would translate well to Unreal 4?

Well thank you so much if you’ve read this far! To summarize my questions into 1; Is the model you Rig and animate always the same model you see when you’re playing the game?
Thanks in advance for any answers!

Oh right, I also added my model to the attachments, should you want to see. little NSFW warning though, it is a female figure, but no pink parts are modeled.



HumanModelForSharing.blend (565 KB)

Not sure if this will help at all, but I put this together to help with getting characters ready to export to UE4. I exported the basic male avatar from UE and imported it to Blender to make note of the rig configuration and bone names. I’m sure there are better documents out there that would help with Blender to UE, but this is all I have at the moment.


UE4_template_rig_bone_names.zip (1.71 MB)

You can always apply your subsurf before you export it to make it look a little smoother in UE4. That way you don’t have to model “all those polygons”.

Thank you so much, that might come in handy sometime soon!

It’s not so much the modeling, I’m more afraid that if the model has a high polygon density the weight painting that comes afterwards will be very bothersome to deal with. Since I can’t weight paint the low poly model and then just apply the subsurf and it’ll deform just the same, or can I? I’ll have to test that… Ok I just tested that, it doesn’t work well. It does automaticly weightpaint the new verts in a gradient, so to speak. But the way it deforms is too different to be of use.