HIgh Poly Corner Problem

isso09

Hey everyone,

I've been trying to figure out how to do corners well in high poly. I've used bevel with some success but sometimes it does weird things..

The topology is exactly the same in both corners, but when I subD one produces a nug and the other does not. Does anyone have a time-efficient solution? I have about 8 of these to fix.
Thank you!

EarthQuake

Most likely, you need more geometry to better support the shape you're trying to create.

Check this thread: http://www.polycount.com/forum/showthread.php?t=56014

Also, post a shot with more of the mesh, so we can see the surrounding geometry, and your reference, so we can see what you're trying to accomplish.

isso09

Thanks man!
Here's a full shot of the piece:


SubD:


This is how I'm trying to solve it:



All I'm trying to do is sharpen certain edges and corners.
Is there maybe a way to do this without splitting polys and pushing verts in a haphazard way? Are there any general rules for corners that I need to learn?

pior

Most likely, you need more geometry to better support the shape you're trying to create.

.

EarthQuake

Start out with 64 sided cylinder
modify into desired shape
add supporting loops
remove loops around the sides, this causes a small bit of pinching but should be fine when you bake.


Alternatively, add an extra set of edge loops, and then carry those control edges down the side a little further, you'll still get some pinching but maybe this is a more clean result, again shouldn't be noticeable when you bake.


Alternatively alternatively, just use a shitload of sides, like 128 or more. This will be harder to work with, but you can do some creative stuff like creating the bits that merge into this as floaters.

sprunghunt

EarthQuake wrote: »

Alternatively alternatively, just use a shitload of sides, like 128 or more. This will be harder to work with, but you can do some creative stuff like creating the bits that merge into this as floaters.

Another method would be to create the zigzag shape as a straight section with a lot of edges and then use a FFD or some kind of bend deformer to make it go in a circle

Danielmn

I agree with you Sprunghunt especially if I am doing it in max.
I would model it flat and then put a bend of 360 degrees on it. And put a shell on it in the end

greevar

EQ:

Why don't you just use two edges at each peak and valley instead of one central edge with support edges? Wouldn't that eliminate the pinching? I think the reason it's pinching is that the geometry is just too sharp.

EarthQuake

Meh, the pinching is so minor here that I would prefer to get a sharper edge on the corner, also, depending on exactly how you did what you're mentioning above, you'de get some slight inconsistancy there with that method I think. But really, the two examples above, I think the 2nd one especially, you would never notice in the bake, so who cares? =D

sprunghunt

yet another way to do this would be to create a tube with a lot of segments then boolean the zigzags out of the top. You'd still have to go and add some support edges but it'd be a lot easier.

isso09

Hey thanks for all the replies, guys! This is my first game model, so I'm probably gonna sound really stupid. Anyway I really appreciate all the feedback. I think what was screwing it up was the spike. It was really hard to resolve them corner pieces. In retrospect, it would have been a lot easier just to keep it on a separate mesh.

Anyway, I think this was the route of all my subsequent problems, but I have a few more questions.
Here is the final sculpt:





I baked an occlusion map (which made my material turn grey, does anyone know how to turn it back?) with mudbox 2011 and this is what I got:




Some of the UV's got messed up as you can see, so I was wondering if that's normal. Which brings me to my next point:



Also done by mudbox.... Should I just use Xnormal? or Did I mess up with my settings? It took my comp an hour to bake 1.5 mil polys with a fairly new computer.

Michael Knubben

If you were going to sculpt it, you've basically gone through all that trouble for nothing. Sculpting is best done on a mesh with uniformly sized quads wherever possible. And if pinching was your concern, you certainly don't show it! Your finished sculpt has a ton of it, in addition to the stretchy artifacts from inconsistently sized polygons.

isso09

MightyPea wrote: »

Sculpting is best done on a mesh with uniformly sized quads wherever possible.

Can you elaborate on what that means? Was I supposed to use edge loops for consistency and keep my mesh symmetrical all around?

And if pinching was your concern, you certainly don't show it

Isn't it better to fix the base mesh so that as little pinching occurs as possible? I thought if I left the pinches there, the sculpt would have been even more f'ed up. Is that kind of stuff easily fixable by subdividing and sculpting manually?

Sage

@ isso09.

What Mighty Pea means is you need have your model topology divided so its as even as possible like a grid. The goal is to avoid a lot of thin polygons and have areas of large polygons because of how subdivision works. When you subdivide a model in Zbrush for example it will place most of new polygons where the smaller polygons are and the larger areas get less polygons. The problem with this is that the large areas is where you normally need the most detail and you won't get it if you don't divide those areas evenly. Try it if you don't understand.

Yeah pinching can be an issue if you need to sculpt but it depends. You make your model and deal with it on a case by case basis. If pinching is a problem you deal with it.

isso09

EarthQuake wrote: »

Most likely, you need more geometry to better support the shape you're trying to create.

So you mean instead of subdividing the mesh, i just manually put edge loops all over the place? I believe I get it now. I thought going from low poly to high was just about hardening certain edges with edge loops. Oh boy.

What Mighty Pea means is you need have your model topology divided so its as even as possible like a grid. The goal is to avoid a lot of thin polygons and have areas of large polygons because of how subdivision works.

Thanks for explaining it, man. I learnt a ton on this model, so the next one is gonna kick ass.

EarthQuake

isso09 wrote: »

I thought going from low poly to high was just about hardening certain edges with edge loops. Oh boy.

Generally, its done the other way around, first creating the highpoly, and then building a simplified low around high. Its a mess to do it low->high.

tristamus

EarthQuake wrote: »

Generally, its done the other way around, first creating the highpoly, and then building a simplified low around high. Its a mess to do it low->high.

Yep.

So, as simplest and generally put as it can possibly be (This is how I go about it, anyways...), it's LIKE this...

1) Build your low poly base mesh to match the general SHAPE of what your goal is. It's up to YOU to keep in mind what the high poly will have to somewhat conform to when baking to the low poly. By this, I mean, you can't have a low poly cube and try to bake a normal map off a high poly model that is a sphere, and try to make that work on a LP cube. Get what I'm saying?

2) Make sure this base mesh has evenly distributed quads / topology. This is because you want subdivision to be even across the entire mesh. If you do not have an evenly distributed topology, resolution will differ when subdividing in ZBrush, Mudbox, etc, causing strokes and details to differentiate in resolution when sculpting, which when noticeable, is terrible.

3) Sculpt the crap out of this mesh...

4) Export a decimated / lower poly count mesh, from the high poly sculpted mesh in ZBrush / Mudbox etc., to use for re-topologization purposes in Topogun, 3D Coat, Maya, Max, whatever.

5) Retopo this mesh.

6) Assuming you have saved iterations of your high poly model, use the one you feel is most appropriate (has the highest detail) for baking normals, Ambient Occlusion, etc., and the new, retopo'ed mesh you just made to bake TO. You can do this using xNormal, ZBrush, Maya, etc.

This is one workflow in a pool of millions, that you will never understand completely. I am NOT saying your stupid - I'm saying that every artist's workflow is different, with different habits, different paths of doing things, etc. You'll one day have your absolute own workflow for doing things, and it will be yours alone. So, by all means, you don't have to follow this workflow to a T. It's whatever works for you....I tried being as general as I could.

I hope you know the rest lol...

Sage

@ isso, you can use meshsmooth for example to give you the grid, it's just are hard subdivision with no smoothing. You need to set how you want your model to be subdivided though. You do this by setting up your smoothing groups and weights for your edges and verts. You can go and manually add the edge loops you need with a tool like split loop, the slice plane works as well. you can also combine this however you want. How you go about it depends on how you made your object. Do what is quicker and easier. Remember these are just tools use them so you get the best results in the least amount of time.

Max you can get loops evenly placed in your model with connect for example.

Michael Knubben

Yeah, sorry for being somewhat unclear there. I did mean 'like a grid', as Sage says. Everything you did before you sculpted would have been fine for a highpoly, but sculpting on a mesh like that is always problematic. Less so now than it used to be, but still.

The advantage to sculpting is also that you can just subdivide something a few times without smoothing, then subdivide once with smoothing and you'll have those smooth edges you were trying to get, without pinching. I noticed you use Mudbox so I quickly googled how to do this in there: "Go and look under the optoins box next to subdivide and uncheck smooth."

As for going low>high, I agree with EQ that it's messy. On the other hand, I generally make the broad shape first, then add supporting edges (the ones that tighten certain edges for subdivision, basically) in a seperate edit poly layer. This gives me an easy way to get rid of them later to have a simplified mesh for the lowpoly. It still requires tweaking ofcourse, but I find this to be a nice way to work for mechanical objects.

edit: here are some links to the wiki that might prove useful:
http://wiki.polycount.com/CharacterSculpting
http://wiki.polycount.com/BaseMesh
http://wiki.polycount.com/ReTopologyModeling

Eric Chadwick's (and co.)done an amazing job on these pages.

EarthQuake

MightyPea wrote: »

As for going low>high, I agree with EQ that it's messy. On the other hand, I generally make the broad shape first, then add supporting edges (the ones that tighten certain edges for subdivision, basically) in a seperate edit poly layer. This gives me an easy way to get rid of them later to have a simplified mesh for the lowpoly. It still requires tweaking ofcourse, but I find this to be a nice way to work for mechanical objects.

Yeah, but this is blockout -> high -> low, which is still very different from low -> high, which is just a huge mess as you're trying to build a usable high from an optimized lowpoly model.

isso09

Hey guys!

Thank you so much for all the info, everyone. You have no idea how helpful your replies have been, and I'm actually about to show you when I post up my final screens of the scene this model is from in UDK.

But first, I have a question about X-Normal. Does anyone know how to get the normal maps to only take into account the closest mesh to the low poly? To show you what I mean, there are various objects overlapping each other, and the normal map seems to reproduce the overlaps instead of being baked individually for each object. So you get this:



I think the farthest high poly mesh overrides whatever the rays hit before it, so I was wondering if there is a setting in X-Normal that makes sure each object gets its respective normals, instead of "being blocked" by adjacent ones... Because so far I've been forced to bake each object one by one.

isso09

Alright, guys. Here are the final shots of my props. I would appreciate all the feedback I can get. If you need, I'll post the maps as well.