Weight painting triangulated Mesh?

[beanster Potato]

Hallo :) So i've been playing around with mesh/blender for the past couple of weeks (it had to happen sometime) and learned how to make (very) basic clothing in blender, rigging and weighting with acceptable results. However, when I import something i've made in MD, the rigging works fine but I cant get the weighting done in a proper way. Since MD uses triangulated mesh instead of quads, I was hoping someone has any tips or hints on how to properly weight triangulated mesh? Or even better, an automatic way on how to convert triangles into quads? Using automatic weights per bone, deforms the mesh terribly for most bones, especially in case of long sleeved garments. The weight paint brushes does'nt show much improvement either. The 'tris to quads' function in blender is'nt super useful plus that also removes the seam lines that I need for uv unwrapping. 

Any info is welcome and yes, im new to this obviously, sorry :) 

Ps. using blender 2.63 & Avastar

[Gaia Clary]

I thought MD had implemented Quads a while ago. Or is it still only announced ? However, it will be painful to convert an MD mesh back to Quads once it has been broken up into triangles.

But anyways i do not see any major problem with weighting a triangulated mesh beyond the known problems which raise from animated triangles (spikes when bending, texturing issues...)

You always can get a base weighting generated by Avastar (using its weight copy tool). Then fine adjust your results using the weight paint tools...

[beanster Potato]

Hi Gaia, thanks for your reply : ) so triangulated mesh can and should be weighted the same way as quad? I guess ill just continue practising then x.x.. doing so with quad worked fine but the triangulated.. well, not so fine lol. Maybe its something else im not doing right.. as a relaxed/rest pose, I use a pose equally to the default MD pose although the MD avatar is a bulkier with shorter arms compared to the avastar avatar (I used SL-MD-avatar.blend as an example to get the avastar avatar as close as possible to the MD av pose) and apply 'bake tpose' function from avastar to that.

Unfortunately MD has'nt come up with quad function yet although they've been planning this since over a year if I may believe their past forum posts. 

[Gaia Clary]

The SL-MD-avatar was an attempt to upload an SL avatar to MD. But what you want is to rig an MD modell to the Avastar rig.

I would try something along this line:

 

• Get the MD character into Blender (i believe they can export their character as .obj)
• Create a new Avastar character in Blender
• Modify the Avastar character by using the Shape sliders and pose mode until it matches the MD Character in shape, pose and size as perfect as possible
• With the above step you should get very close to the MD character. If you really need some fine adjustment to get "the perfect fit" then you could edit the Avastar rig to match the joints perfectly. But i wouldn't do that unless i get forced to do it.

Store the results so far as your MD workfile.

Optional:

• Copy the weights from the Avastar character to the MD character
• Bake the MD character to T-pose

Now you will want to hide all avastar parts (see the display settings in the object data properties) and keep only the MD character visible. Thus you have added your own character mesh for your subsequent work.

Save what you have your enhanced MD workfile.

 

• Now import the MD dress or whatever garment you make. It should already fit to the MD character from your enhanced MD workfile.
• Copy the weights again from the avastar rig to your garment.
• Bake your garment to T-Pose

That should be all. You should be done by now.

If you have NOT(!) edited the avastar armature (see above) then you will just export your garment to SL and wear it. (but see the note below..)

If you have edited the armature, then you have to export the armature along with the mesh and import with weights and joints. Then it should fit again.

does that give you an idea ?

 

IMPORTANT NOTE: due to a bug in current Avastar you always must export the armature along with the mesh to avoid distortions. But you do not need to import the joints to Second life. So you won't break anything (just need to add the armature tp ypur selection when you export your mesh)

[beanster Potato]

Thanks a lot for your detailed answer Gaia, you've gave me quite some homework Before to start; by creating a new Avastar character, you mean copying only the lower/upper/head meshparts - adjust the shape and use the same avastar armature/bones for the new shape, right?

This does make me curious if the clothing made in MD still fits the SL avatar when following your method? For now (still testing and trying) i've imported SL-MD-avatar into MD to fit clothing to before to import into blender to do the skinning/weighting. I thought maybe when fitting clothes to the default avatar shape of MD, the same clothes would'nt fit the SL avatar.. or does'nt this matter any more with the upcoming deformer? Sorry im not very good at explaining.. neither at english

[Ashasekayi Ra]

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beanster Potato wrote:

Hallo

So i've been playing around with mesh/blender for the past couple of weeks (it had to happen sometime) and learned how to make (very) basic clothing in blender, rigging and weighting with acceptable results. However, when I import something i've made in

MD

, the rigging works fine but I cant get the weighting done in a proper way. Since MD uses

triangulated

mesh instead of quads, I was hoping someone has any tips or hints on how to properly weight

triangulated

mesh? Or even better, an automatic way on how to convert

triangles

into quads? Using automatic weights per bone, deforms the mesh terribly for most bones, especially in case of long sleeved garments. The weight paint brushes does'nt show much improvement either. The 'tris to quads' function in blender is'nt super useful plus that also removes the seam lines that I need for uv unwrapping. 

Any info is welcome and yes, im new to this obviously, sorry

 

Ps. using blender 2.63 & Avastar

---

 

There are a number of reasons you shouldn't try to rig/skin a triangulated model. To make matters worse, MD models have Delaunay triangles which basically have no edge flow what so ever. This makes it great for cloth simulation but horrible for models that need defined edge loops for weighting to an armature and animation. So, I have used two different techniques for using an MD clothing model for SL clothing.

Also, I've found that exporting your SL avatar from Blender at 1000x scale and using it in MD works pretty well. Then, you just export the cloth from MD at 0.001 scale.

Option 1: Retopology

In my opinion, this is the best option. You basically make a new mesh on top of the MD model. This new quad mesh has the proper topology needed and has edge loops  that can be easily weight painted and tweaked.

Retopolgy Links:

• http://cgcookie.com/blender/2011/08/08/retopology-with-the-bsurfaces-add-on/
• http://cgcookie.com/blender/2010/08/30/retopology-and-normal/

 

Option 2: Weight painting by proxy

Another method I have used is to make a few generic low poly reference models that I can quickly use to transfer weight to an MD model. I have these models already weighted well. For example, I'd have a simple box modeled shirt that was the same size as the MD shirt. However, it is very low poly and doesn't have any details of the MD top. I just use it to place weights and tweak them. Afterwards, I'd transfer the weights from that low poly shirt to the MD shirt. Then, if I need to tweak weights in some area, I'd tweak it on the low poly reference then copy those weights back to the MD model. This method can sometimes be quicker than the other. But, I just prefer the visual results of using the retopologized mesh in SL over the native MD mesh with Delaunay triangles.

Note: You can convert a triangulated mesh automatically to quads in Blender using Alt+J, but it won't give you proper edge flow.

 

[Gaia Clary]

Ashasekayi Ra wrote:

Option 2: Weight painting by proxy

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Hi, Ashasekayi,

I find your proxy approach interesting. Let me recap (to see if i understand correctly) :

 

• You take a basic shape with good topology for animation
• then add optimal weighting to that shape,
• and finally copy these weights to similar shapes with different topology ?
• thus you reuse proven weightmaps for new garment (using weight copy) ?

Is it like that ?

Is that the same method that we use when we copy the weights from the default Avatar to a new mesh based character ?

 

BTW: A few days ago i received a note about an idea that is currently evaluated in Blender:

   

Maybe one day that could become interesting ... well, who knows

[beanster Potato]

Thank you for the links and info Ashasekayi, i've tried to do the retopolgy routine using Topogun last week but.. it made me want to continue just buying full perm mesh instead of trying making my own. The bsurfaces plug-in looks a little less traumatic and time comsuming so i'll give that a go : ) 

[Ashasekayi Ra]

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Gaia Clary wrote:

Ashasekayi Ra wrote:

Option 2: Weight painting by proxy

---

Hi, Ashasekayi,

I find your proxy approach interesting. Let me recap (to see if i understand correctly) :

 

• You take a basic shape with good topology for animation
• then add optimal weighting to that shape,
• and finally copy these weights to similar shapes with different topology ?
• thus you reuse proven weightmaps for new garment (using weight copy) ?

Is it like that ?

Is that the same method that we use when we copy the weights from the default Avatar to a new mesh based character ?

 

BTW: A few days ago i received a note about an idea that is currently evaluated in Blender:

   

Maybe one day that could become interesting ... well, who knows

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Yes, you understand it exactly right, Gaia. That method works pretty effectively with garments that have a simple/basic construction. Hopefully, I'll have time to crank out a video on it.

And, thanks for the video clip. That looks pretty interesting indeed. It reminds me of the MD setup somewhat. I hope someone puts the patch in a Blender on graphicall so everyone can play with it.

[Ashasekayi Ra]

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beanster Potato wrote:

Thank you for the links and info Ashasekayi, i've tried to do the retopolgy routine using Topogun last week but..

it made me want to continue just buying full perm mesh instead of trying making my own. The bsurfaces plug-in looks a little less traumatic and time comsuming so i'll give that a go : ) 

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Bsurfaces really is pretty fun to work with and does the job pretty quickly. 

Edit: Use the newer version called "Bsurfaces" not "Bsurfaces GPL".