Modeling vs sculpting; organic modeling; keeping meshes clean and organized

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  2 Weeks Ago
Modeling vs sculpting; organic modeling; keeping meshes clean and organized

Hello.

I'm someone who has been drawing for a while, and recently I've decided to have some fun with 3d, so I was hoping to make a few game assets, which consist mostly of medium to high-poly, organic meshes. So far, I've been playing around and creating some simple things, but I'm facing a few problems regarding modeling in general, and workflows for the kind of thing I'm trying to do:

On the topic of modeling, it's something I like the idea of, since it's really precise, but I'm having a lot of trouble with it when trying to model organic things, because I simply can't seem to keep things - vertices, and faces, and so on - organized and clean, and even with low poly meshes I find that sometimes I just get frustrated because it feels like I've lost the flow of faces and edges, and it reaches a point where I just feel like I can't even touch anything without making it worst. This is by far the most frustrating obstacle I'm facing, since I'm really not sure how to fix this thing that sounds so simple. It's even worst because I get so focused on trying to align 4 or so verts in a way that doesn't trigger my OCD too bad, that I completely lose all track of what I wanted to do. Do I just need to be really patient and careful when changing verts around, is this one of those cases where, if I really have to move stuff around that much, it means I already have a fundamental problem, and should just be trying to remove complexity instead of changing things around, or is there something I'm missing? Any pointers you can give on this, or any resources you can point me to, would be very much appreciated.

Also, I can't decide what place sculpting has in what I'm trying to do, and I don't know whether I should be sculpting most of the time, or just using "traditional" quad modeling all the way. I've been looking into this, and since it's something meant to be used in real time rendering, the poly count needs to be kept in check, which with sculpting seems to be hard to do, and the topology needs to be kept tight, due to real time deformations as well, which, again, doesn't seem to be something sculpting cares much about. I've seen three suggested ways of dealing with these two issues: the first is that we create a high poly, sculpted model, and then we kind of model a simpler mesh using it as a guide; the second is sculpting the mesh with roughly the same complexity we want in the end, and then retopologizing it so it plays nice with our bones; and the third is auto topology tools. The obvious question to ask then, is if these solutions are viable, or if I'm just better off using traditional modeling, with perhaps a little help from basic sculpting tools, since most 3d software packages now-a-days seem to have at least rudimentary sculpting tools.

Thank you in advance.
 
  2 Weeks Ago
Polygons are really old technology that suffers from surface topology problems, always. It used to be OK technology 20 years ago when 3D was kind of new. Now its just really old.

The only reason its still around is because all current GPUs - Nvidia, AMD - are essentially simple polygon drawing hardware with some shading capability.

One way around topology problems is to get a retopo algorithm like Instant Meshes to generate new topology for you:

https://github.com/wjakob/instant-meshes

This algorithm is already built into some 3D modelers like Modo.

Another is to retopologize manually/semi-automatically with software like 3DCoat

 
  2 Weeks Ago
I'm confused, Skeebertus. Polygons are far, far older than 20 years - they are thousands or hundreds of thousands of years old.

What other technology are we using these days that doesn't utilize shapes? Are you talking about NURBS? B-splines? Are curves not also ancient technology? I've been using them for 40 years.
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  2 Weeks Ago
Originally Posted by skeebertus: Polygons are really old technology that suffers from surface topology problems, always. It used to be OK technology 20 years ago when 3D was kind of new. Now its just really old.

The only reason its still around is because all current GPUs - Nvidia, AMD - are essentially simple polygon drawing hardware with some shading capability.

It doesn't much matter how old polygons are, the reality is that we must deal with then, and this will be the case for quite a long time still, due to how efficient our algorithms for dealing with triangles have become. Ultimately, the artist must conform to the constraints of the medium they're creating for, and in the case of 3d, I believe there's really no way to escape things like triangles, texturing, bump mapping, and so on, at least not completely, because, even if everything's done automatically for you, you'll still have to be aware of what was done, and how well it'll work as the final result.

As someone who's not only a programmer but also loves math, especially the field of geometry, I love the topic, so I'm fairly familiar with these things, and in my opinion, even if we found a way to do it (which no doubt we will), I don't see many benefits in moving away from triangles, especially because if we did, that'd probably destroy texturing and general image mapping, and we'd require entirely new software suites (incredibly powerful ones, I feel), to do anything what so ever.

Originally Posted by skeebertus: One way around topology problems is to get a retopo algorithm like Instant Meshes to generate new topology for you:

I am aware that automatic topology is a thing, but is it worth it for what I want? My main concern is with how efficient these algorithms are, especially due to the lack of context: they don't know what will bend or how it'll do so, and they don't know which parts can be simplified, and which can't. I imagine that, even with automatic topology, you'd have to do a fair bit of tweaking to get things up to the task, and I must wonder if it's just more efficient in the long run to just model while occasionally using some sculpting to push and pull things into place.
 
  2 Weeks Ago
@ShiroAisu,
It depends on what you're making and ultimately it's up to you to find a workflow that works for you. If it's a fairly detailed piece, the standard workflow is sculpt first not worrying about topology. Then, retopologize... usually by hand in some preferred retopo software. Topology can be confusing so leaving it out during the creative part can be liberating. Again it really depends on what you are making. You may find that some things are just easier to poly model.

Auto retopology tools are getting better and if you are careful with them they can be useful under certain instances. For anything important it's typically done by hand.  You will need to learn about topology and where to place your edgeloops and poles. 

If the mesh is getting out of control when sculpting. You will want to use subdivision levels. That way you can do broad changes at lower subdivisions and details at higher subdivisions. Also, it can be difficult in Zbrush to get nice sweeping curves. When you are trying to make a nice curve and running into problems, try using the Move brush at different sizes to carefully fair the curve. It takes practice.

It can be helpful to use Zremesher along to way. Maybe start with Dynamesh( or Sculptress Pro in 2018) to rough out the form and then Zremesh in order to get a more manageable mesh that can be subdivided. You can do this several times along the way. You would still ultimately retopo by hand in the end.

If it's a humanoid character larger studios are using a standardized base mesh with good topology to start from. This way you don't need to retopo and makes it so rigging, skinning and blendshapes can be automated to a degree.

You will have learn from trial and error how much you can do with maps and what will need geometry. OCD is good up to a point but don't let is slow you down.  There is a lot to know.  Start simple and go through the whole process and do it again and again until you understand.
 
  2 Weeks Ago
i use a lot of those autoretopo tools... but i fill in the important stuff by hand...
if i start with a dynamesh or a tessellated mesh i do first an autoretopo and delete the parts i need to redo by hand...

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