Imported rigged mesh is clipping through avatar

[Dexter Chaffe]

I'm a veteran 3D artist who has decided to give a go at making my own clothes in Second Life. Everything seemed fine with a sample open shirt I've made and made sure to adjust it so no clipping occurs (as to avoid forcing alphas on people wearing it) like so:

The Shirt in Blender

Then I tried to upload the shirt in Second Life and right off the bat the shirt was clipping on my friend's avatar. So to double check I made a copy of the .dae with the sample avatar provided by Avastar based upon LL's fitted mesh provided, seen in the preview as looking "fine". When I uploaded that on its own however and wore the shirt the problem persisted.

Houston, we have problems

Include joints is NOT ticked in and there are no weight issues happening on the Blender side as far as I know, seeing the preview shows the shirt being perfect.

 

What am I doing wrong?

[Cathy Foil]

The avatar in Blender is the default female avatar shape Ruth.  The avatar in the photo wearing your shirt in SL is not the same shape as Ruth.  Her breasts are bigger that's why the poke through.

Your shirt is fairly loose fitting so it is a pretty good candidate to be rigged as Fitted Mesh.  With Fitted Mesh you rig to the Collision Bones of the skeleton not the Normal Bones of the skeleton.

Collision Bones change their scales as the avatar shape changes.  Vertices weighted to them will scale either bigger or smaller.  If you weight the right side of the shirt that is covering the right breast to the RIGHT_PEC Collision Bone then that area of the mesh will get bigger or smaller when the avatar's breast change shape.  It will also bounce if the person is using avatar physics.

I suggest buying AvataStar for Blender if you are going to try and make Fitted Mesh or even regular rigged mesh.

Hope that helps.
Cathy

[Dexter Chaffe]

I did use Avastar to facilitate the weighting process for fitted mesh actually. However as I've vaguely explained (sorry!) in the main post when I put the shirt on while using the Ruth shape myself the clipping areas were still apparent. Putting the shirt on a Ruth mesh dummy in a sandbox has the shirt fit perfectly, so in terms of upload that should have worked fine. 

My primary suspicion at this point is that I've missed some details on the rig itself, or Second Life is totally messing with me.

[Cathy Foil]

The biggest problem with Fitted Mesh is that the avatar itself does not change shape by changing the scales of the bones.

It chances shape primarily by using morphs so getting clothing mesh to change size in the same way by changing the scales of the Collision Bones is extremely difficult.  Just to be clear the Collision Bones change scale when you change your appearance setting in SL.  You can't change the scales of the Collision Bones in Blender or Maya or any other program you can rig in.

The vertices of the shirt around the nipple area.  Are they weighted 100% to the Left or Right Pec collision bone?

If they are then it is definitely the problem between how avatars change shape with morphs and Fitted Mesh changing shape by changing the Collision Bones.

I so wish LL would let us have the Mesh Deformer as well as Fitted Mesh.  Rigging is so much easier with the Mesh Deformer.

[Gaia Clary]

There is one major rule:

If you use the same shape in Blender (with Avastar) and in SL then any mesh (fitted or non fitted) should match perfectly when worn.

There is one exception:

For some unknown reasons the match is not perfect on the left foot.

So if you get poke through then

 

• You do use different shapes in Blender and in SL
• Or you do not use Avastar's Collada exporter
• Or you have messed with Preserve Volume in Blender(*)
• Or you have used an older version of Avastar (for fitted mesh you should use Avastar-1.1-RC3)
• Or there is a bug in Avastar

(*): I am still uncertain about preserve volume. It is clear that this feature is not supported by SL. However there are a couple of confusing observations regarding usage of preserve volume. We have this on our todo list for Avastar-1.2

Should you be confident that there is something wrong with Avastar then please open a support ticket on our blog. We will respond on that.

[Monti Messmer]

Your shirt can fit in Blender and SL, but the SL Avatar keeps moving and bending then this morphing problem occurs (explained earlier)

Try to have a steady T-Pose on a posestand and do the weight part for all sizes is a pain.

Monti

[Cathy Foil]

Just out of curiosity what viewer are you using?

[Dexter Chaffe]

Thank you for all the responses everyone! I've been busy at a games event all day so I couldn't get to replies as soon as I'd have liked to.

When I set Ruth on T-pose in SL (I use the latest Firestorm) most of the clipping occurs at the upper back, tricep area of each arm and the love handles. Oddly enough the exact same avatar shape exported from Blender (as a solitary mesh rather than worn) with the shirt fitted on directly the shirt had absolutely no problems. 

My Avastar version appears to be 1.1.2 on my Blender 2.70a, so I'm not entirely sure all the latest updates would fix issues pertaining to the base female avatar clipping in-world when wearing the shirt, while that same shirt is absolutely fine when put on a mannequin of the exact same shape as well as Blender and in-preview before uploading the mesh.

I do hope to get this resolved, as I've had dozens of ideas to experiment at making base clothing in SL obsolete for years now. Thank you all again for the assistance, hope to hear more from you again soon!

[Gaia Clary]

---

Dexter Chaffe wrote:

When I set Ruth on T-pose in SL (I use the latest Firestorm)

---

I have been given a handfull of "definitions" of what Ruth is, so in first place which Ruth do you mean exactly ? Especially how can i get this to inspect it ?

[Dexter Chaffe]

The Ruth in question is the test female avatar loaded by the client when you go on Develop > Avatar > Character Tests > Test Female. I was told this is the exact same shape used by Avastar's default.

[Gaia Clary]

And this is total crap. who told you that ? Create a new default shape, wear that and all is well.

I must admit that i managed to hide this detail. I wil edit the docs now.

[Dexter Chaffe]

I.. believe I've seen that bit of detail on one of the Avastar guides or over on here in the very SL forums. I'll give that a try and see what turns up!

 

UPDATE: I tested the shirt on a brand new shape and it works!... sorta. It's clipping at the forearms right now so I'm trying to figure out what may be causing that considering I gave the sleeves a lot of leg room.

[Gaia Clary]

The Ruth that you used is something undefined. I believe this is a historical avatar (maybe the first one that was ever defined) and i suspect it exists just for confusing users... (ok, i do not know what its purpose is to be honest)

The shape that you get when you create a new shape in SL is what we decided to use with Avastar, because that is the only reliably defined shape in the entire system.

well, things are never easy with Second Life. Maybe we should make Avastar more complicated so that it matches better with the expactations :matte-motes-evil-invert:

[Dexter Chaffe]

Considering how odd SL is altogether I wouldn't be surprised if a more complicated add-on would produce better results, haha.

Still, how in the Linden almighty would flared sleeves clip through the forearms is beyond me. It's like the forearms themselves don't want to be covered.

[Gaia Clary]

then it is time to file a report to us...: http://blog.machinimatrix.org/avastar/tickets/

[Nalates Urriah]

First take a look at this: http://blog.nalates.net/2013/04/23/second-life-shape-export/

The next problem is from the SL Avatar using morphing with the shape sliders and fitted mesh using 'bone scaling'. The rates of chnage for the sliders are different in the avatar and fitted mesh. So, any close fitting clothes will have poke-through at sizes much different than the one designed for.

This problem is a good reason for switching to full fitted mesh bodoes where the rates of change from the sliders would be the same for body and clothes.

 

[Nalates Urriah]

The idea of a default avatar is very ambigious. There are also many people that have no idea what the REAL default shape is, as you have found out. Gaia uses the idea that I think is most accurate, the new shape created by the viewer is for most purposes the default shape. (for the complexities of 'default shape see: http://blog.nalates.net/2012/05/20/second-life-mesh-clothes-blender-2-6-setup-2012-tutorial/2/ ) The actual difference in the mesh layout between the different files is very small.

There is a fix for some avatar weighting and mesh layout issues that is floating around. I used to know which viewers had implemented the fix and which hadn't, but I've forgotten. So, even using the 'new' shape as default may vary depending on which viewer you use.

You can find the fix in the STORM-1800 JIRA item. It only changes what you see in the viewer with the change applied. As far as I know none of the avatars models being used in Blender, 3DS, Maya, euc. make use of the fix.