detailed zbrush mesh to game engine(unity3d)

gamenoob

Hi,
I am kinda new to CG.I sculpted a detailed box in zbrush.Now the polygon count is really high.So I used decimination master to reduce them.Even now my model is too dense for game engine.Now what should I do?

Barbarian

You have to retopologize it in ZBrush, or use TopoGun, 3DCoat, etc. Decimation master hardly ever results in a decent enough mesh for in game. Once you retopo you can UV unwrap it and cast a normal map from the hires version.

Joopson

Decimation master DOES work, but it isn't going to get awesome results, shading wise.

What I would do, depending on the object, is decimate it (being sure to set your desired polygon count... I think it is by thousands, so 3 would be 3000, .5 would be 500. I think. Can't quite recall)
Then use UVmaster.
Then to xNormal to bake the normal maps, and stuff.
Should give you serviceable results.
Though if you're serious about the model, then yeah, retopo it, and UV it yourself.

ceebee

Joopson wrote: »

Decimation master DOES work, but it isn't going to get awesome results, shading wise.

What I would do, depending on the object, is decimate it (being sure to set your desired polygon count... I think it is by thousands, so 3 would be 3000, .5 would be 500. I think. Can't quite recall)
Then use UVmaster.
Then to xNormal to bake the normal maps, and stuff.
Should give you serviceable results.
Though if you're serious about the model, then yeah, retopo it, and UV it yourself.

I hate this practice dude, it's pretty annoying to see environment artists that do it this way when it's not just a simple rock or something. Decimation master isn't that great, and there is a high chance you'll end up with super weird long triangles that are sometimes even invisible to the naked eye so to speak.

Just learn how to retopo, theres a bunch of different programs that can do it, and once you learn how to do it in one package you can pretty much get it done in any of them.

@the OP: If it's just a simple "box" then just use a low poly cube, maybe bevel some edges, soften the normals (or harden them if you need to) and fit it around your high res as close as possible. Not only will this give you a cleaner and probably more optimized result but you'll have a much easier time UVing it that isn't garbage UV Master UVs

Joopson

Ceebee, I agree. It makes me cringe too, but as I said, "if you're serious about the model, then yeah, retopo it, and UV it yourself."

The only time I do such a thing is if I'm throwing a placeholder asset in, or something, quickly to play with lighting, et cetera.

I definitely agree that zbrush's Decimation and UV master will never replace good old fashioned elbow grease.
But it does get the job done, if you aren't too serious about it, or if it's something organic, like a rock or cave or something.

gamenoob, if you hope to be an environment artist, you should do it manually. It'll be worth it for the practice and experience. These things add up, and you definitely don't want to be a lazy artist in this industry.

gamenoob

thanks for replay,guys.You have been very helpful.
"Referencing a high poly mesh and doing simple edit/simple create/draw/loft and finally making a low poly mesh"

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This whole process is called topology?

Is the following approach right?

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I make a very dense mesh in zbrush from concept.Then without using decimination master or uvmaster,I go straight to topogun and make a low poly version using tools like simple create/edit/draw.Then I export the low poly mesh as obj.Then I import the low poly mesh in zbrush and do the "uv master".I get a uv.I copy it somewhere(though I dunno how!). Then
I import the high poly mesh(the very dense one).And in zbrush I copy the uv of low poly mesh that I created earlier and paste it for dense mesh. At this point I have high poly mesh with UV and low poly mesh with uv.Then I take those two mesh into xnormal and bake for normal map and AO map.And the rest process,you know.Bringing Ao map on photoshop for defuse texture and at last into unity3d.

mazz423

So a high to low process involves building your high poly mesh (dense mesh) whether it be through zbrush or another program.

Then once you have that finished you want to retopologise it, which is essentially creating an entirely new mesh using your high poly as a reference. The key here is to maintain enough detail in the new lower mesh to retain enough of the high poly's silhouette; whilst remaining within a sensible polygon limit. (I wouldn't worry about this right now if you're completely new to this, just get used to the process, but don't go crazy of course) If you're using topogun that's great, really nice simple program to use, plenty of tutorials out there already on the tools it offers, if not zbrush has its own retopology tools within the program.

One thing to point out however, if you are using topogun, if you're high poly is very dense its a good idea to decimate for retopology as topogun isn't quite as robust as zbrush when it comes to handling hundreds of thousands of polygons. Just decimate it so that its around 100,000 polys in zbrush, topogun tends to handle anywhere between 100,000 - 200,000 quads fairly well in my experience.

UV master is a plugin within zbrush that basically automatically generates a uv map for your selected mesh, it's key that you learn how to do this manually yourself but I'd recommend looking into specific tutorials on this at some point so that you have a true understanding of the process. Now, you dont have to copy the low poly's uvs anywhere, once the uv map is created its created, just reexport the low poly and you're ready to bake down the details. Your high poly doesn't need a uv map of any kind and copying uv maps isn't entirely possible as a uv map is basically a flattened form of your mesh, i.e. if you have two different meshes with differing topologies they'll flatten differently.

Baking is an entirely different minefield but is extensively covered in many tutorials online and in a lot of the threads over in technical talk.
This thread really helped me out when I was new to baking stuff like normal maps and AO maps.
http://www.polycount.com/forum/showthread.php?t=81154

Apologies if you knew most of this already and I wasted your time with a long post, I just felt it would be helpful to read a brief breakdown of each stage if you've never attempted it before. Hopefully something in there helped in some way.

gamenoob

mazz423 wrote: »

So a high to low process involves building your high poly mesh (dense mesh) whether it be through zbrush or another program.

Then once you have that finished you want to retopologise it, which is essentially creating an entirely new mesh using your high poly as a reference. The key here is to maintain enough detail in the new lower mesh to retain enough of the high poly's silhouette; whilst remaining within a sensible polygon limit. (I wouldn't worry about this right now if you're completely new to this, just get used to the process, but don't go crazy of course) If you're using topogun that's great, really nice simple program to use, plenty of tutorials out there already on the tools it offers, if not zbrush has its own retopology tools within the program.

One thing to point out however, if you are using topogun, if you're high poly is very dense its a good idea to decimate for retopology as topogun isn't quite as robust as zbrush when it comes to handling hundreds of thousands of polygons. Just decimate it so that its around 100,000 polys in zbrush, topogun tends to handle anywhere between 100,000 - 200,000 quads fairly well in my experience.

UV master is a plugin within zbrush that basically automatically generates a uv map for your selected mesh, it's key that you learn how to do this manually yourself but I'd recommend looking into specific tutorials on this at some point so that you have a true understanding of the process. Now, you dont have to copy the low poly's uvs anywhere, once the uv map is created its created, just reexport the low poly and you're ready to bake down the details. Your high poly doesn't need a uv map of any kind and copying uv maps isn't entirely possible as a uv map is basically a flattened form of your mesh, i.e. if you have two different meshes with differing topologies they'll flatten differently.

Baking is an entirely different minefield but is extensively covered in many tutorials online and in a lot of the threads over in technical talk.
This thread really helped me out when I was new to baking stuff like normal maps and AO maps.
http://www.polycount.com/forum/showthread.php?t=81154

Apologies if you knew most of this already and I wasted your time with a long post, I just felt it would be helpful to read a brief breakdown of each stage if you've never attempted it before. Hopefully something in there helped in some way.

Thank you very very much,specially for the referred thread(I will of course follow it later.).So I do not need uv of dense poly mesh.I need uv, only for low poly mesh,right?

I tried the approach,i told earlier.Yes you are right.I can not copy uv of low poly and then paste it into high poly.In trying to do so,zbrush gave me a nice error.So I created the uv of low poly only, with uvmaster.Then save the model as obj.Then on xnormal,I put the high def mesh and "low def mesh with uv".all settings of xnormal was default except one.From "tools",I used "ray distance calculator".There I saw two pair of max-min value.I noted the average of two max value.And put the value in both "maximum frontal ray distance" and "maximum rear ray distance".I then baked 2048 normal map.And brought low poly mesh,defuse map and normal map into unity.But look at the result,isn't the cube in detailed and blocky. I want it looks like high poly mesh but it does not look like that.I do not know what has gone wrong?!

I have done a lot of hard surface modeling,uving in maya.When it comes to the hard surface,I can do uv with maya easily.Though it is a time consuming-boring-repetitive-matching blocks game type task,I did those nasty thing a lot.Wait a min!Can I do uving of hard surface model with uvmaster? I think I have to try.However,when it comes with organic model,characters etc,I have no idea how to uv those until uvmaster came into my knowledge.Is there any other technique of uving organic model?

JamesQuall

I gotta say I've been getting good at creating models, but the whole process of getting them in a game engine is a lot harder than I expected. Really wish there was a program that would streamline the process, the whole uv thing combined with baking, flipping, and knowing how to create each map properly is throwing me for a loop.

Glad I found this thread though seems like it will probably help.

frg6789

You should check out my video I'm making. I'll go through the entire process including baking.

Check it out!

cryrid

I make a very dense mesh in zbrush from concept.Then without using decimination master or uvmaster,I go straight to topogun and make a low poly version using tools like simple create/edit/draw.

You can use Decimation Master before retopology so that whatever program you import it into doesn't have as much data to try and process. Just don't rely on Decimation Master for the retopology itself.

So I do not need uv of dense poly mesh.I need uv, only for low poly mesh,right?

Pretty much. There are times when having UVs on the sculpt can be useful, but in general they are not needed.

But look at the result,isn't the cube in detailed and blocky. I want it looks like high poly mesh but it does not look like that.I do not know what has gone wrong?!

I wouldn't export from an Zbrush obj straight to Unity, if that's what you're doing. If you have access to Maya or another program, load the model up there and export as an FBX so you can control the vertex normals, etc

gamenoob

Hello guys,thanks for replay.Sorry for digging ten day old thread.cryrid, I do not understand the last point you made.controlling vertex normal stuff.What is it?