How to Attach a Head with Different Edge Count (Maya)?

[Chronoloco]

I'm loving my rigged characters so far, but really don't like that faces don't have rigs. I created a separate head in Maya (fbx) which is rigged & has some blendshapes, etc... And I feel like I found a decent place to chop my Fuse character's head off fairly cleanly. My question now is, my custom head has a higher poly count than the Fuse body. I know how to connect edges of two meshes, one by one, to connect them. But I'm not sure if there is a good way to connect edges, if one object (throwing out random numbers) has 33 edges, and another one has 97 or something like that. For now I kind of faked my way through it, by putting my head in place, and then just bending edges & vertices to make it LOOK like they're one object, but I feel like that's a sloppy way to do things.

Any suggestions on how to attach our own custom heads, in a program like Maya? (part of the problem right now is, if I use the Maya Rig script, to export baked animations with mesh, etc... I get all kinds of crazy errors. (Not at my computer so can't remember them off the top of my head) but when I tried to import that modified character into Unity, his head was floating several feet above his body, not attached at all, and his arms had disappeared.

I remember the errors had something to do with too many weird curves, not being able to find hip joint rotation x axis or SOMETHING like that, and a few other things that went over my head. I can post more specific error messages later if anyone wants to take a crack at them, but for now, I'm just curious what process other people would suggest, for attaching our own custom heads, post-rigging, without it breaking the scripts functions (like copying an animation to the rig, etc...)

[xyzt]

Loop cut your way on the body to higher counts on the neck? Subdivide the body for higher counts on the neck? Reduce poly count on the head until it's closer, then loop cuts on the body to finish matching the count? Convert them to patch or curves, then merge? I have no idea, just throwing things out.

[Chronoloco]

Since the head has more edges than the body/neck, I would have to do the loop cuts on the body if I go that route. Will that mess with the autorig script at all? I know it's pretty particular about any changes you make, as far as extracting & combining & naming and stuff. I don't know how it reacts to additional edge loops though. I need to make sure all of the script functions will still work if I manually cut vertical loops in the body. I can test that out and see if I can get the results I'm looking for without breaking the script. I'm still nervous about the baked export function (from the script) breaking if I remove the original Fuse head. I wish there was a quicker way to just say "grab the head, grab the body, hit combine" and call it done. (and have it automatically attach the edges and fix poly counts automatically) but I know that's not how it works. Thanks for the suggestions though, I'll give those a shot later when I get back in there.

[BadTertle]

So long as you delete your non-deformer history after mesh changes like that, you should be pretty safe.

The automatic merging of different edge count/flow parts is one of the things that make Fuse so cool. Fuse actually started as a Stanford research project tackling this complicated problem.

We do have features planned for blendshapes and user-created imports, but it will take time for the R+D and implementation. For now, major props on delving head-first into Maya (she's a fickle one, but I couldn't live without her)!

[Chronoloco]

Yeah, I got nervous with the deformer history stuff, because I accidentally deleted "the history" of my blendshapes at one point, and went into panic mode for a minute (luckily I have a backup). But I generally don't delete any sort of history unless someone specifically tells me to, ha... I'm still at the "walking on thin ice" level of wrapping my brain around Maya's logic. But yeah, I'll try that out and see where it gets me. I tried lowering the polygon count of the head, but it ended up looking too weird (didn't translate well). So maybe increasing the poly count on the body will be the solution. I just don't want to end up with something with such a high poly count that I can't use it with solid performance inside Unity.

And yeah, Maya is a pretty amazing program. And it's clearly one of those "gets better the more you use it" programs. Every new thing I learn in there makes me feel like I'm accomplishing something. If I can figure out a decent process that doesn't take TOO long, for sticking custom heads, onto the Fuse bodies, I'll be golden. And if a future Fuse version can somehow let us import our own heads, and have it automatically lock everything in place, without making us worry about edge counts, that would be a dream come true for me. I'm not 100% sure if that's what you're saying it could (potentially) do, but if that's the case... AWESOME! I can't wait for whatever features are added once an update is released.

[BadTertle]

I'm not sure what your character design is, but a cheat that many games use is a prop to hide the head/torso connection (necklace, scarf, collar, etc - see LA Noire). There may be a clever way to avoid the problem altogether and leave it as a separate mesh depending on the design. (it also saves on memory as its not trying to blendshape the entire body)

[AqP]

If the character is clothed then Fuse already cuts out the unseen faces between the head and hands and feet. The body remains a single object but the edges around the neck, wrists and ankes are not joined to anything. Do you really have to join the mesh?

[xyzt]

I was kind of thinking converting them to curved surfaces, like Shade 3D does, would merge simply. And then convert back to mesh. Though, I'm sure you're already done with this task. Of course... Shade is kind of wierd... you can stack curves to create mesh simply by throwing them in the same folder you made to organize them.

[Chronoloco]

Originally posted by AqP:

If the character is clothed then Fuse already cuts out the unseen faces between the head and hands and feet. The body remains a single object but the edges around the neck, wrists and ankes are not joined to anything. Do you really have to join the mesh?

To be honest, I don't know if I really need to join it or not. My end goal is to put the model in Unity, and when I do that right now (chop the head off the Fuse model, position my custom head in place, don't worry about attaching it, but link it to the head bone or whatever so that it'll rotate, etc...) Then when I import it into Fuse, the arms disappear, and my head shoots 2 feet or so above the rest of the body (with nothing linking the two). So I figured maybe if I had those "properly attached" then it would fix the issue, but it could be something as simple as deleting the history of SOMETHING. I just don't want to delete the wrong thing on my head mesh, and end up losing all of my blendshapes. And I don't want to delete anything on the body that would cause it to no longer be synced with the Mixamo rig, because I'd rather not have to re-weight everything, and reattach everything (defeating the purpose of the Mixamo rig in the first place).

Originally posted by BadTertle:

I'm not sure what your character design is, but a cheat that many games use is a prop to hide the head/torso connection (necklace, scarf, collar, etc - see LA Noire). There may be a clever way to avoid the problem altogether and leave it as a separate mesh depending on the design. (it also saves on memory as its not trying to blendshape the entire body)

My character design is basically just a basic Fuse model (with a T-Shirt) so the head is sticking out of the top of the T-Shirt, and my custom head doesn't have MUCH of a neck (think of it as stopping right around where the Adam's apple would be or whatever). So I was wanting to basically use the shoulders/lower neck of the Fuse model, and connect my head with that. (Which is why I ddn't just remove the entire Fuse neck, keeping ONLY the arms), because I still need part of the Fuse neck for what I'm trying to do. And I don't REALLY want to add any crazy clothing or whatever else around the neck, because a guy with a T-Shirt walking down the street with a thick scarf would look really weird.

To be honest, FOR NOW, I don't care THAT much about having "a little bit of a seam" there though. All that I really want, is to be able to import the character, with the full body Fuse/Mixamo rig, and my custom head, without it popping off the character and floating above the body. I'm sure I'm just missing some sort of simple history step or something somewhere along the lines, if you guys are saying I shouldn't HAVE to attach all of the edges.

I was also under the impression that you can't have "holes" in your characters or something though, if importing them into Unity. (I could be thinking about a rule I read for some other software somewhere though). But I was under the impression that (as an example) if your arms go inside a T-Shirt, but are technically missing polygons on the inside where you can't see it, then that would screw something up. It's very likely I misunderstood that rule though.

[AqP]

You wouldn't need a scarf, just tweak the neck area to sit under the t shirt collar.

I'm not familiar with Unity, but I do know the kind of things that go wrong in Blender. Head jumping up 2 feet sounds like an unapplied transform on the head part of the mesh. When you bring it in to your modeling tool, in Blender I would be sure to apply location, rotation and scale transforms. Location should be 0,0,0. Rotation should be 0,0,0. Scale should be 1,1,1. Hopefully you can translate this thought into the Maya equivalent.

Sadly I don't have a suggestion for the disappearing arms, unless they are disappearing into the body, in which case it's to do with the bone hierarchy at the shoulder and the rest pose.

I am having to edit the Mixamo skeleton to match the number of bones and bone hierarchy for my platform (Ogre). When I use Makehuman instead of Fuse, I also have to convert the rest pose from A pose to T pose.

[Chronoloco]

Ok, I feel like I'm getting pretty close to where I need to be. (I decided to scrap the idea of the blend shapes on the head for now, since I don't even know how to use those in Unity yet, I'll just mess with those separately for cutscenes or something, I don't really need tons of facial animations while my character is walking back & forth fighting people). Plus, I was able to use them to get a custom "fighter / angry" face which is good for now.

But now the only question I have at the moment is... One final error (warning) exporting from Maya... Does this mean anything to anybody? I'm ASSUMING it's one of those warnings I can just ignore, and assume it won't mess up anything since it says "to ensure interoperability"... But still, I've come this far, I'd like to be able to knock out any final warnings if they're relatively easy to fix.

---------------------------------------------------------------------------------

Warning: Animation curve tangent type changed to User (159)

The plug-in has changed some animation curves tangents type to User to ensure interoperability. This mode change will not affect the animation curves' values
Hips_translateX
etc...

[BadTertle]

You can pretty safely ignore that type of warning (especially if this is a key on every frame motion - its just informing you that its changing tangent types for sub-frames). The only possible issue is if its hand-animated with you tweaking and/or breaking the tangents (and even then its trying to be smart about the conversion). While some engines would have issues, Unity is actually fairly friendly about holes in meshes and whatnot. It does not need to be watertight.

While you are super close to your result, I'd encourage you to try out a simple blendshape in Unity test with a cube or something. The blendshape system is new and could use a little improvement, but its pretty straightforward and easy to use (blendshape keys exported from Maya play from an FBX just fine, but having joints and blendshapes together had some issues). What we've done at Mixamo for our Unity Blendshapes on faces is to keep the body joint and facial blendshape animations as separate fbx files and add them together with a very simple mechanim setup.

[Chronoloco]

Ha, ok... Yeah, based on your explanation, it sounds like I don't need to worry about the warning, since I was trying to export a non-animated T-Pose...

As for the blendshapes, my main reason for skipping that for now is, when I imported my character into Unity, ALL of the blendshapes for the head, were stuck to my characters back like a back pack. I didn't want them all to be visible obviously, since they should JUST effect the main head mesh. So instead of leaving thousands of additional polygons of overlapping faces stuck to my character'a back for no apparent reason, I just deleted them for now.

I still have a copy WITH the blendshapes though. Any idea where I went wrong with the export/import here? Something that would cause all the blendshape heads to be stuck to your character's back in Unity? (I got the main head positioned properly, but even when I tried to move all of the blendshapes into the exact same transform position as the main head, you could still see ALL of them when the game started, which basically just made my head look thick, distorted, overlapped, etc...

[Chronoloco]

Ha, I was putting the entire FBX file into my scene, because that's how all of my other non-blend shape fbx characters worked in Unity. I didn't even think to open it in the inspector to see exactly what I was putting in my scene. So I had 30 some blend shapes being loaded into my scene inside of FBX file. I think I'm sort of getting the hang of this though. Through a lot of trial & error, I realized I can't access blend shape controls through my Hierarchy at all in Unity, but if I go to the main scene window, and click on my head, not once, but twice, for some reason that takes me to an Inspector page where I can access the blendshapes. They still feel a bit awkwadd in Unity, compares to the nice blend shape control board in Maya, but I'm ALMOST where I want to be with this. Thanks everyone for all of your help so far!

[Chronoloco]

I'm at the point where I can put the blend shape head in my scene (by itself) and it works, and I can put my Mixamo rig in by itself, and it works, but if I smooth skin bind my head to the Mixamo rig in Maya, and then load the full model, it breaks the blendshapes in Unity. APPARENTLY you can't bind skin on a blendshape model for use in Unity? Am I missing something here?