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Zbrush- Mesh Hair- Hoping for Help!


Keanna Spyker
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Hello everybody! I'm working on learning how to sculpt mesh hair in Zbrush (4r6) via this forum, youtube, and tutorials that I can find. I don't have a background in AD modeling, but I do have a bit in clamoring, so forming the mesh isn't generally problematic. Generally. :|

I'm running into a few issues, and I was hoping that someone might be able to help me? Here's my problems:
- I've been using Dynamism and Decimation Master for lessening the amount of active points.
        o= I don't know how much a normal SL hair is suppoed to be vertex wise?? When I first imported it, it was land impact was 36 (or 11k polys); now, I've uploaded it at land impact 18 (5k polys).
        o= When I get to the tips of my hair, they turn into flat, panel like shapes, and I can't inflate them. Is there a way to trim off verts that I don't want, without creating a hole? 
        o= I was reading (I don't remember where) that when you do modeling for SSL, don't do anything that adds triangles. Apparently my hair mesh has triangles. Is there a way to convert it?

Here is an image of the mesh (the 11k version), sized and attached (not rigged) on a dummy avatar. I applied a basic hair texture to it, as I'm currently reading up on polygroups and uv unwrapping for faces. (The current mesh is currently one face?)

hairexample.png

If you have any tips or tricks, please feel free to post them. There is next to NOTHING specifically for modeling hair- it's all on the general character.

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The land impact is not bad. 36 or 18 is decent. If you look at normal prim hair they can be upwards to 250 prims. So a 36 or 18 is fine. You are doing great to keep below the normal prim amount. Land impact should be somewhat equivelent to prim count

 

As far as the tips Turing into blunt ends I am not sure on.

 

When you upload mesh. Sl converts your quads to tris. But modeling with quads are usually best.

 

I normally do not use Zbrush so i really cant make any suggestions on how to fix the tips other than ad some edgeloops/verts and pull them out. Blender is my cup of tea..

 

I would suggest using the qRemesher plugin in Zbrush. It will make nice quads and does a great job on decimating

Here is a post i made not too long aGO on how well qremesher works http://community.secondlife.com/t5/Mesh/Marvelous-Designer-2-Help/m-p/2112393#M22711

 

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Honestly, I wouldn't sculpt that kind of hair.

Actually, I don't think I've ever seen sculpted hair that looked good, except in the case of stylized cartoon characters where it doesn't need to be realistic. The very nature of using brushes gives a clay-like quality that just doesn't suit the shape of natural hair.

If you're going for an anime look, fine -- I've seen that done well -- but realize that those cases involved really talented and experienced people. Besides, for a ponytail, I'd probably reccomend not using mesh (at least not for the tail-end), since a flexi-prim would probably give more desireable results.

Also, if you're using 4r6, you should have access to zRemesher. That replaced qRemesher, so far as I'm aware and is much better.

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Dilbert Dilweg wrote:

The land impact is not bad. 36 or 18 is decent. If you look at normal prim hair they can be upwards to 250 prims. So a 36 or 18 is fine. You are doing great to keep below the normal prim amount. Land impact should be somewhat equivelent to prim count. .... 
When you upload mesh. Sl converts your quads to tris. But modeling with quads are usually best.


Wouldn't the lag from having an object that LI be problematic? The original hair at 36 LI was 11k verts, so I was thinking that minimizing it was the best option. I've been told that a really well sculpted avatar can easily be done in under 10, so I couldn't imagine why a hair should be higher, if lag was going to be an issue? Please correct me on this if I'm off. I guess I don't understand the weighting well enough.

 

Thanks for the advice on the quads and triangles! That takes a bit of worry off my mind.

 


Rahkis Andel wrote:

Honestly, I wouldn't sculpt that kind of hair.

Actually, I don't think I've ever seen sculpted hair that looked good, except in the case of stylized cartoon characters where it doesn't need to be realistic. The very nature of using brushes gives a clay-like quality that just doesn't suit the shape of natural hair.

 

If you're going for an anime look, fine -- I've seen that done well -- but realize that those cases involved really talented and experienced people. Besides, for a ponytail, I'd probably reccomend not using mesh (at least not for the tail-end), since a flexi-prim would probably give more desireable results.

 

Also, if you're using 4r6, you should have access to zRemesher. That replaced qRemesher, so far as I'm aware and is much better.


Even those experienced and talented people started somewhere- I'd like to think for only having worked in Zbrush for a few weeks now, I'm not doing too poorly. :P Obviously, the more I work on my meshes, the better they become.

As for the ponytail, I'd like it meshed because I'm going to rig it to the body for a litte movement. I personally don't like the movement of flexi prims- they all move like sheer fabric. As time goes on, I'll play with rigging, and I'll be happy with the movement I find.

 

I've just started messing with a combo of zRemesher and Dynamesh** (correction from previous post). The combination seems to be doing really, really well for me. Thank you for the suggestion!

 

As a side, I was curious if anyone had also found a way to move the "seam" of a UV texture? Is there a way to move it, or do I just have to be mindful of it when sculpting?

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There is definitely a way to move the UV seams to wherever you want.

In ZBrush, you would do so with the UVMaster plugin. Watch a Pixologic video or any short tutorial about it and you'll be up and running. The idea there is that you can attract seams to areas which are "darkened" by ambient occlusion,  and/or also freehand paint areas that you want to protect from seams or attract your seams to.

These don't need to be precise at all, just a general ballpark "line" painted on will do fine, since the UVMaster process is still fully automatic.

That's the way you can get your UV seams to go exactly where you want!  Btw, sculpting hair and clothing was one of  the things that set the masters and the amateurs apart in ancient Greece classic sculpture ;)  So don't give up on it, you can get amazing results the more you practice!

For your final result lowpoly, you can use this step by step ZBrush workflow:

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

Sculpt your model using all your favourite Zbrush techniques, Dynamesh etc. You get something with millions of polys.

Decimate to about 15-20k points (or whatever is enough to make sure you keep almost all your detail in the model)

Run zRemesher on it 

Run zRemesher a second time on this, and see if you get an even better result! (often you do)

Use UVMaster to automatically create UVs for the lowpoly model (this is where you decide where the seams will be)

Subdivide the lowpoly model until you are at approximately 4 million polygons again

Use polypainting features, Spotlight, etc. to colour it

While on the highest subdivision, go  Texture->Create from Polypaint. You will see a texture appear there in the box.

Press "Clone". The texture pops over to the Texture palette.

In the texture palette you can flip the texture vertically (needed for SL) with a button. And, it's here that you can export it as a PNG, to start working on it in Gimp or whatever you like (if desired).

Go to the lowest subdivision where your lowpoly mesh is, and export that as a collada file for Secondlife.

Done!

Seems like a lot but you'll zip through it after only a little bit of practice. This workflow is designed to introduce UVs only at the last possible stage, because you don't want them around when you're sculpting your millions-of-polys mesh, they take up resources and slow you down. 

Another alternative way to work is to sculpt, polypaint (all without UVs), then create a lowpoly mesh as I described, and give it UVs. Save both the highpoly and lowpoly meshes. The highpoly will have polypaint information in it and no UVs. The lowpoly will have UVs but no texture yet. Use the free application xNormal to bake different maps including ambient occlusion and normal, and colour, to the lowpoly, from the highpoly polypainted one.

Extra tip: for zRemesher,  when "adaptive" is turned on (default), it's trying to maintain quality as hard as it can, which can be not what you want, because it then is allowed to increase your polycount. If you disable this or dial it back, you can force zRemesher to give you the best result it can for specific polycounts you're aiming at (like we do for Secondlife!).

 

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For trimming off unwanted faces, you have a ton of options.

My favourite is using ctrl-shift  and drawing a polygon selection with one of the tools (box, cicle, lasso, curve etc)  then ctrl-shift click to isolate it so the rest of the model is visible, while the part we want gone isn't.  Go Geometry->Modify Topology->Delete Hidden.  This gets rid of those points.  If you are still in Dynamesh, you can just ctrl drag on canvas to redynamesh and it will close any holes neatly by itself.   There is a Close Holes command in Modify Topology that you can use.

You can also use masking, to protect the part of the model you want unchanged, then a clipping brush or clipping curve to smush those "bad" faces into shape.

You can also use those new trimming brushes, which cut the mesh, then automatically resulting close holes in one step.

Finally, you can pull up a Slice Curve brush,  and slice off a part of the model as neatly as you want, which creates new polygroups there. Do a ctrl-shift click like before to isolate, Delete Hidden,  and then close hole, (or redynamesh). This lets you get really nice smooth cuts because Slice Curve creates smooth new edges around where it cuts automatically.

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I cannot even begin to tell you how useful that workflow you have given me really, truely is to me. I wish I had known that earlier in my working, because it would have saved me lots and lots of headache and worry! Did I mention I (platonically) love you?


I've been doing mostly this, but I've been afraid to work high than 25k in my base model-- I normally haven't been making the lower subdivision levels, but I see that they're used for LOD now. Wow, that takes a good bit of worry off my shoulders!
I've mainly been working around the model, just moving, smoothing, remesh and dynamesh to force the tips away. Those cutting techniques are really going to help me. I haven't tried them yet, but I already know how I'm going to usse them!

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Glad to help!  I only get to look at the forums rarely, but in case of needing a bit of consulting about something, feel free to IM me in world.

The mesh upload part (the SL Mesh uploader) is a tricky business in itself, but I eventually worked out a workflow for it too. The thing to realize is that while you are in ZBrush, just think about making a finished, lowpoly model with great textures that capture all the highpoly details you sculpted.  This is going to be your "Highest"  LOD.

Which lower LODs you will need to work hard on and which can be left to automatic or skipped  is going to depend a lot on what type of item you're building, its actual dimensions in-world and how far away will the viewer usually be. It's sort of a juggling act of its own that you have to get to grips with, that isn't ZBrush-specific.  I'm staying away from trying to export LODs directly from ZBrush, because so often that ends up being counterproductive. The best I found is to focus on the "Highest", then depending on what's needed, you could reload that lowpoly (with textures and UVs) back into Zbrush and experiment with Decimation Master using the "Keep UVs" option turned on.  This lets you generate lower poly versions for specific LODs (there are only 4 in total to worry about so it's not so bad)  that you decided are important to your item.

For a piece of hair, I'd personally use the same model for the Highest and the one below, and then either send in my own Decimation-Mastered versions for the lower poly LODs (halving the number of faces with each step is a pretty good rule of thumb), or even just be quick and use the SL automatic decimation for those lower LODS.  Since it doesn't matter so much what the hair looks like when it's seen from 1/2 a sim away, it's an item that must look best at up close and medium distance.

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