Not all faces are usable Zbrush Model?

[Rucy Byron]

HI all

 

I have made a item of mesh that consists of 5 separate faces (cardigan, undershirt and 3 buttons) using polygroups in zbrush. When I bring the model into SL I can independently texture 3 of the 5 faces, the other two don't seem to allow me to add the textures to them, they don't show up as independent faces. Does anyone know why this may be happening? Any help much appreciated. :)

[Codewarrior Congrejo]

Generally you can make for SL a maximum of 8 faces . (equals 8 polygroups in Zbrush)

It's hard to judge from guessing a screenshot could be helpfull to see the polygroups.

It could either be that  - depending on what method you used to define those groups - with i.e. grouping from colorizing maybe 2 groups accidentally got the same color and thus being seen as one group. (also happens sometimes when using the mask - grouping)

The Polygroups could be inconclusive and thus not being read out properly. Or also misinterpreted by the collada exporter.


Maybe attach a screenshot.

PS: can  you select the additional faces at all, or are they not accessable / selectable once the model is uploaded to SL ?

[Rucy Byron]

Here are a couple of screen shots, there are 5 faces, the three buttons, the undershort and the cardigan. I can add a texture to the cardigan, to the undershirt and to one of the buttons but not the other two, I cant selesct them as faces once uploaded to sl. Thanks for your response. Any ideas?

 

 

 

 

[Rucy Byron]

Here is an image from in SL, I can add textures to the cardigan, undershirt and top button, but not the other two buttons?

 

 

EDIT - each piece is a seperate subtool, i 'grouped visible' while each subtool was selected and visible to give me the 5 groups. I then made all the subtools visible and 'merged visible' with the 'UV' button highlighted.

[Codewarrior Congrejo]

hmm looking at the colors it seem the undershorts and the cardigan have the same polygroup.

the 3 buttons have defenitally different ones though.

Did you join / merge the parts 'after' you assigned the polygroups or did you merge them before?
Zbrush has the tendency to loose or screw up polygroups when being done before merging. Not allways but happens sometimes.

What you could try it just selecting those parts again, separately. "Hide" all faces that do not belong to a group and then assign a group. Repeat it for the next part. and so on.

Another issue i whitnessed with Zbrush is when you i.e. have UV-Unwrapped all the pieces while they have been still 'single' objects and then 'Merge' the whole thing. This results in overlapping UV maps. Which is no issue when working with normal 3D software because you can assign clearly different materials to them / or move the UV islands if you don't want them to overlap.

And with z-Brush allone and the DAE exporter in there it seems sometimes to produce issues resulting in the faces / material groups not being selectable.

Which could explain why you can only select that one button but not the other 2 (cause they might be laying on 'top of another' so to say) i am not 100 % why the exporter or SL seem to have that issue, but it has happened to others as well.

try to merge them all (if they arent already) remove the polygroups. then assign them fresh (and dont forget to hide the faces you dont want to belong to one group - its the safest way of preventing several known issues) and then unwrap the whole thing later again either in Zbrush (by unwrapping based on polygroups/UV islands) or in blender / whatever software you are using.

 

PS: just read your latest post - if you want to Rigg that and dont want the buttons to be static attachments you should merge them to the same mesh. The fact they are not merged would point exactly to one of the above described problems. (the 3 buttonsd should be merged into the same mesh as the shirt is - the jacked too if you want to rigg this as one piece)

[Rucy Byron]

Thanks for your reply, i added a adit to the post above. I made the subtools seperate poly groups individually then merged visible with UV highlighted. The undershirt takes its texture fine, and seperate from the cardigan. I didnt want the seperate textures combined onto one map, each part has a seperate texture map that i want to assign to the faces. I can great a new UV layout for the whole piece with seperate islands, but wanted to get higher resolution textures for each piece. When i combine them all on to one map the buttons are not on top of each other, but like i said, I would prefere each face to have its own 1024 texture map.

 

edit - in reply yo your PS: all the groups are merged into one model for the reasons you describe, I will be rigging it as one piece.

[Codewarrior Congrejo]

i can understand the separation from the shirt and the jacket. But the buttons are so tiny you should rethink if you don't want to add them to a corner of i.e. the UV map of the shirt's UVs. (I'd strongly not suggest giving each button a 1024x1024 texture space. That would be pretty much waste of render time =) for the server side and the client side.

Also i was wondering is there a reason you want to have all 3 buttons separated ? do they get different colors?
If not they could just all use the same space on the UV map. like in one of the corners and then move all 3 button UVs right on top of each other. the shirt will surely leave enough space free even when almost filling a whole texture, to put the buttons  together in one corner.

Do you only unwrap it in Zbrush or going to blender /etc to do the UV unwrapping? Zbrush can become quite troublesome for such certain tasks =)

PS. but yeah it seems to be one of the troubles you run into when merging already UV'ed objects and polygroups. I'd still suggest either redióing the Polygrouping and mapping now after they have been merged. Or take your model into blender and make a controled face-/material-assignment in there and also the UV unwrapping. Would give you way more control.

I can help you through it in case you didnt use blender for that before.

[Rucy Byron]

OK so I can pile the three buttons directly on top pf each other on a map with the undershirt, i didnt realise that would work, I will try that, and have a seperate texture for the cardigan. Hopefully that will work! Thanks for the help, I will let you know if that works out for me. Help appreciated.

[Codewarrior Congrejo]

Sure thing, and no problem  =)
Good luck and report back when you should need help with unwrapping in Blender. Or run into new problems.

[Rucy Byron]

I think my next big task is going to be rigging, I am sure I will run into problems in workflow, i have never made clothes before, first attempt. I will let you know how it goes. Thanks once again

[Toysoldier Thor]

Tell me how your rigging experience goes.

[Rucy Byron]

I am having to go back to my high poly models merging the buttons on the undershirt and retopologizing the undershirt with the buttons as one piece. I already had high rez textures that fit on the existing UV's and I can't see a way of merging the low rez retopologized buttons and undershirt without losing the UV's, so can't project the high rez detail from the original models.

The frustrating thing is, the polygroups should simply work as faces in sl!!!!!!!! I would love to know why this is happening, or if there is another work around. Other models I have made work fine. I do agree however that each button doesn't need its own high rez texture map.

The trials and tribulations of a mesh noob

[Codewarrior Congrejo]

Heya,

you actually don't need to retopo the buttons within the shirt. a simple 'merge' will do the trick. but of course, yes after merging you will have to make the UVs new.  and use polygroups for the unrwapping.

Unfortunately the controls in ZBrush's UV unwrapper kind of reach their limitations when it comes to overlaying and really controling the UVs. Thats why i suggested doing this rather in Blender and directly also assign the material - faces in  there. this way it is secure that it will accept them as separate faces instead of the oddities you run into when doing it in Zbrush allone with more complex things like this.

Generally the polygroups from ZB should work as material / faces, but as i mentioned there are some unwated things that can happen and prevent it to work out propperly.

Just merge the shirt and the buttons and export as DAE or as OBJ and open it in blender and do the unwrapping etc in there. You anyways have to get 'friends' with Blender for rigging them =)

If you need help on how to unwrap this and how to layer the buttons on top of each other, and how to assign materials. Just let me know and i'll make you a little step-by-step tutorial.

[Toysoldier Thor]

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Rucy Byron wrote:

Thanks for your reply, i added a adit to the post above. I made the subtools seperate poly groups individually then merged visible with UV highlighted. The undershirt takes its texture fine, and seperate from the cardigan. I didnt want the seperate textures combined onto one map, each part has a seperate texture map that i want to assign to the faces. I can great a new UV layout for the whole piece with seperate islands, but wanted to get higher resolution textures for each piece. When i combine them all on to one map the buttons are not on top of each other, but like i said, I would prefere each face to have its own 1024 texture map.

 

edit - in reply yo your PS: all the groups are merged into one model for the reasons you describe, I will be rigging it as one piece.

---

Rucy....

How did you make seperate textures for the sub-tools of the model?  I would like to do the same thing for my more complex models so that I can get more texture information on the overall model.  i.e. if I have a model with a male and female subtool and each of the polypainted and even material system baked.... how do I create a 1024x1024 Texture map for each subtool in the model to apply to the model in SL?

[Codewarrior Congrejo]

I am not 100% sure about your question related to create an independent UV for each 'subtool' since subtools are independent and thus can easily have separate UV maps, by just unwrapping each subtool on its own.

However if you, like Rucy Bryon, want to know how to handle and deal with multiple UVs and Image maps on one mesh  / object -  insides of ZBrush - in order to get more Textures and higher details onto it...

...I have made you guys (and for all others struggling with that question) a full tutorial in the mesh forum:

http://community.secondlife.com/t5/Mesh/Z-Brush-Tutorial-Multiple-UVs-and-textures-on-one-mesh/td-p/1938327

 The 'merging' process and preserving the independent UVs of the former separated subtools which have been created within the process might also answer your question. In case it was related to subtools that will be 'merged' into one object in the end.

Cheers, Code 

[Rucy Byron]

Hey Code, that's great, very informative tut, much appreciated.

I did however work out that I in fact could select the buttons as faces on my original model, it was a case of camming right up close and behind the button, so my cam was almost half way through the button, then I actually could select it as a  face and apply the texture! I do agree that more planning and clever use of polygroups to create independent texture islands is a good idea.

So I eventually got my model into blender, I took the jacket/cardigan without the undershirt/buttons in as I want to rig with and without the undershirt. I managed to rig and copy weights from sl avatar, upload into sl and wear the cardigan

As you can see here the jeans I am also wearing are showing through the cardigan, although when it was made it I was sure to create enough space there for most sizes of butt to be covered when worn. I didn't customize the weight painting, is this the reason why this is happening? Or is it necessary to change the shape of the model back in zbrush and re-rig etc? I am new to all this and, again, any and all help/advice is appreciated.

Hey Toysoldier, I believe Code answered your question about seperate textures on merged polygroups?

[Codewarrior Congrejo]

1.) yes - tweaking the weights is in 99% necessary. The chances that the weights will work just 'as is' are really just luck and not reliable : )
(Note: it can work when your mesh's topology is extremely similar to the default avi's topology, when you copy the weights from it. But even then you sometimes need to tweak a bit at least)

2.) what could be happening? There are several things that could cause this and its most likely a combination of them:

- you bend your mesh outwards at the back, but not enough to cover the particular shaping of this pair of jeans.

- The weightpainting: the weights in this area are stronger on your cardigan then on those pants and the contraction towards the bones is stronger.

- The copied weights didn't cover this spot (but I don't think that's the case here or they would not 'bend' with you around that area)

 

Possible solution - ways to solve this:

Make some 'generic', simple pants mesh of circa the same shape as these are. And these here seem to be a bit fluffed, especially around the belt area, so make sure yours are too.

Best is to make yourself  screenshots from those pants (without wearing the cardigan) from front, side and back-view.
To see where they stick out most and how they are shaped, to recreate this with your placeholder mesh pants. (I have a feeling - by looking at the screenshot - that it fluffs out quite a bit already in the lower back, instead of just on the behind.
(build them to suit the default model to get a possibly most realistic result on how the most pants will be) 

Then parent them to your skeleton as well. (just do it with 'automatic' weights to have a quick and dirty way of them moving along the skeleton - for your testing purposes)

Shape your cardigan's mesh to cover those and not having them stick through.

Now 'pose' your skeleton into generic poses that might be encountered inworld, and while doing that keep switching between the posing and the weightpainting modes to fine tune your weights until the cardigan behaves like you wanted.


PS: It will be hard to make cloth that will 'suit' to any possible pants. Especially when its something 'long' as a cardigan.
And taken into account that mesh-pants can have all sorts of shapes and even 'higher' placed behinds or broader legs etc. So best practice is to inspect some mesh-pants that are being sold a lot in SL, and build yourself a 'worst scenario' pants,  where everything is kind of far off from the body, and 2 further ones of the most typical sold shaping / sizes (like skinny, and one for more body fat). And make 2 or 3 versions of your (i.e..) cardigan to fit those generic pant sizes (and body types).

Should you still have issues, add us a screenie of the weightings  to inspect if it has issues in this area.

Cheers, Code =)

[Rucy Byron]

OK, I  see what your saying, better to have several options to be worn with different styles of pants. I understand the principles of weight painting, but am so unfamiliar with Blenders UI, it reminds me of the first time I opened Zbrush and tried to do anything lol. I have bookmarked some video tuts to watch later, but if you, or anyone can direct me to some useful info/tuts relating to weight painting work flow life would become so much easier.

[Codewarrior Congrejo]

http://vimeo.com/18335506

Specifically for SL clothes:

The complete Blender documentation about all weight-tools:
http://wiki.blender.org/index.php/Doc:2.6/Manual/Modeling/Meshes/Weight_Paint
(some of them like the gradient, are only available from version 2.66 on)

PS: some of the tuts are older and talk about 'boneheat' its now called 'automatic weights' in the newer blender versions (just to avoid confusion)

[Rucy Byron]

Great, thanks, I had seen the SL specific tuts, or most of them, the rest are new to me, so along with the others I found and bookmarked I have some viewing/reading to do! Good to stretch the brain though right

[Codewarrior Congrejo]

allways! never stand still, that's the death of every creative mind =)