Evaluation of the Fitted Mesh Solution

[Medhue Simoni]

Well, despite being swamped with many different projects, I could not resist taking a quick look at this new fitted mesh solution. First, let's start with LL's download. Why FBX? Do we not use DAE? Does LL not understand that Blender doesn't import FBX inheritly? Does LL not understand that not all FBX files are compatible with other versions of programs, specifically 3ds Max? I'm assuming LL did not supply weights for the collision bones, as I'm sure Gaia would have included them. How did LL test any of this without weights on the collision bones? Did LL test anything? These are just questions off the top of my head, but It's still troubling. At the very least, LL should have supplied something that shows us exactly what polygons are used for every morph slider. Nope, we got unusable FBX files.

Now, let me go into the good stuff. Thanks to Gaia Clary and the Avastar team, we did get a version we could play with. I recommend getting the Avastar addon for Blender, if you plan on making fitted meshes. This is what I used to test out the fitted mesh solution.

My first observation was that we have to weight the meshes twice. First you must weight the mesh to the SL bones, and then to the collision, or volume bones. In some cases, you can use the SL bone weights and copy them to the collision bones. With collision bones, we get a few more bones than the SL bones. All of the new collision bones need weights, which you must do almost totally blind, as there is nothing that shows you were the morphs are for those bones. You can use the shape keys to morphs the region you are working on, to see what areas are being morphs. This is still a very long process of trial an error. As my only reason for testing it all was to see if it would all work, and how exactly it is done, I did not fully weight everything totally, but just enough to test it all. Some areas, that I just copied from the SL bones, I did see that the mesh sits above the default avatar's mesh. I'm not sure why the mesh does this, but I'm sure those weights are correct. This is going to make tight fitting clothing not a good fit. I suppose you could create the mesh to fit into the skin of the mesh in Blender, and this might give you less of a gap in SL, but I have not tried it.

As I did not completely finish the weights on the top I was testing, I can't really give a good analysis of how it all works out in the end. Why didn't I finish the weights? Well, like I eluded to, we don't have anything that tells us where the morphs are exactly, so I'd just be weighting, reweighting, and reweighting until I got things close. I just don't have the time for this. It's 1 thing to weight bones that animate, which most people understand  how to get good weights, It's a whole other thing to weight things you have no way to test outside of SL. Literally, it is weight, log in and test, reweight log in and test. Again, I'm perplexed by LL releasing files with no default weights on them. At least with that, we'd have something close that we can adjust. It also worries me that we have 2 sets of weighted bones. To people who are not familiar with weighting, how are they going to get 2 sets of perfect weights, even if we get the default weights. The way things work with weighting, default are not perfect because the mesh is not in the exact same position of the original mesh, so there will be differences. If the creator has a problem, how will they know it is not the weights on the animated bones, or the weights on the collision bones? It's not a problem for me, but I can see how it will be for others.

Here are a few suggestions that I'll make for those wanting to make fitted mesh clothing. Remember, I'm just an animator, not a clothing designer or a mesh expert, so take my words with a grain of salt. If you are a clothing designer or want to get into it, I will first suggest getting the Avastar addon. 2ndly, I'll suggest weighting your first set of clothing using a full shirt, with sleeves, full pants, and socks. I suggest this so that you have a set of clothing that has all the weights you need to copy to any other article of clothing. Spend as much time as needed to get a set of PERFECT weights for the animating SL bones, and PERFECT weights for the collision bones. You can then use those weights on any other clothing you might need to weight. I'd save that blend file as your default file to rig and weight clothing with.

That's about as much as I can say about it all. If any1 has any other suggestion, please do post them here.

[Gaia Clary]

Hi.

I have started a page on Collision Bones. This is preliminay and it still lacks a few details, has no images, no video, etc. But maybe it can help a bit for now:

http://blog.machinimatrix.org/fitted_mesh_survival_kit/

Hint:I have added a blend file with a demo skeleton.This is NOT the official skeleton, but its very close to it. In fact it is an Avastar skeleton adjusted as close as possible to the "default female SL shape".

Please feel free to give me feedback for improving this page by any means.

I hope it is of some help.

[Masami Kuramoto]

LL's failure to provide an Avatar Development Kit has puzzled me for years. I mean, how hard can this be if even Cloud Party's super small dev team gets it right? Without third parties filling the gaps (deformer, liquid mesh, materials, Avastar, Chip Midnight's clothing templates etc.), LL would be lost. It's like there is no one left in-house who fully understands their software.

[Cathy Foil]

Hey Medhue you might find this helpful.  Here is a link to Autodesk Plug-in and Converter Archives.

http://usa.autodesk.com/adsk/servlet/pc/item?siteID=123112&id=10775920

Now the Plug-ins are only for Maya but on the same page just below the Plug-ins is a section for Autodesk FBX Converter program.  It is a FREE stand alone program.  With this program you can convert a newer FBX file into an older version one that might be compatible with Blender.  You can also convert an FBX file to a DAE file.

I am using Maya 8.0 and the FBX files LL provided are a version I can not open or import.  I can't even open the Maya files they provided.  I asked LL if they would provide the Maya files as MA files instead of MB files since I can open up the MA files in a world processor and edit them slightly so they will open in my version of Maya.

So what I ended up doing was using the converter to convert the FBX file LL provided to an older version which I was able to import.

I don't know if you can manually change the scales of the Collision Bones in Blender but in Maya to check how the weighting is I can change the scales of the Collision Bones one by one to get an idea of how the mesh will change in SL.  It is still flying kinda blind since the scales changing in SL when you move the sliders probably don't change equally in all three axis of XYZ.

At first I was figuring adjusting the weights of my mesh for the Collision Bones was going to be 3 or 4 times the amount of time it takes to adjust the weights of a mesh weighted to just the normal skeleton but that estimate might be a bit low.

[Gavin Hird]

The thing about the Autodesk 2013.3 covertor is that if you run the two supplied rigged FBX files for female and male respectively throught the converter, the resulting dae files will not load for 2 different reasons:

 

1. The female file does not have recognizable skin weights and joints so you get a regular rather strange mesh uploaded. 
2. The male file produces a Error: element is invaid message.

On trying to work directly with the FBX files in my modeller – and I have only done this for the male file so far I find that the supplied figure has only bound 42 bones in the skeleton to the mesh, wereas the skeleton in the file has 50 bones. 

I then tried to re-bind the 50 bone skeleton to the mesh figure and it produced a dae file that would upload to SL, but the avatar had its head stuck up its bottom so to speak. 

What I found what that the order of the bone hierarchy in the file was wrong, so upon reordering it, it would produce a rigged mesh that uploads to SL, can be worn and responds reasonably well to changes in the avatar shape dials. 

Wrong hierachy as in the FBX file

   

 

Correct hierarchy

The correct hierarchy shall result in a block in the dae file that shall look like this:

 

<Name_array id="ID19696368Controller-Joints-array" count="50">mPelvis mHipRight mKneeRight mAnkleRight mFootRight mToeRight R_FOOT R_LOWER_LEG R_UPPER_LEG mHipLeft mKneeLeft mAnkleLeft mFootLeft mToeLeft L_FOOT L_LOWER_LEG L_UPPER_LEG mTorso mChest mNeck mHead mSkull mEyeRight mEyeLeft HEAD NECK mCollarLeft mShoulderLeft mElbowLeft mWristLeft L_HAND L_LOWER_ARM L_UPPER_ARM L_CLAVICLE mCollarRight mShoulderRight mElbowRight mWristRight R_HAND R_LOWER_ARM R_UPPER_ARM R_CLAVICLE CHEST LEFT_PEC RIGHT_PEC BELLY RIGHT_HANDLE LEFT_HANDLE PELVIS BUTT</Name_array>

 I will do the same testing for the female figure and uplaod working files later. 

 

 

 

[Gavin Hird]

Here is a link to the male dae file: Basemale

The mesh in this file has just the default skin weighting produced out of Cheetah 3D. 

[Gavin Hird]

Here is the link to the female dae file: basefemale

Same issues here with the original FBX; only 42 bones bound and the hierarchy was wrong. In addition the base figure did not have the -90 deg rotation burned, so that added to the twisted mesh. 

Also this file has the default skin weights that Cheetah 3D applied when binding the 50 bones. 

[Medhue Simoni]

All good info every1. I'd like to see more about people's experience with collision bones, but of course we all need working files first.