[First low poly attempt] Sword !

Burpee

Hi !
I'm trying to learn the low-poly workflow, and i need some advices.

I'm doing a sword for one of the dota's hero

Here's the workflow i'm going to do,

- BaseMesh in Maya and Creating the UV
- Importing the BaseMesh in zBrush
- Sculpting some details and exporting Normal Map

Then what should i do ?
- Importing the low poly mesh in Mudbox and Paint diffuse in 256x256 texture rez
or
- Importing the high poly mesh in Mudbox and Paint hight rez texture then scale it down in photoshop ?

And at the moment i'm stucking in the UV map creation, i know it's essential to optimise the UV space,
here's 2 version i did, ( i'm using mirrored UV )




As you can see i'm tryin to maximise the detail on the Number 1 and number 3 & 5

So any advices ? am i doing right ?

Thanks

skodone

i think the second version looks better and it also looks right and good to me :P
maybe you can straighten 5,6,7 a bit but i thinks its ok

Cay

You said you wanted to paint in 3d... so it doesn't necessarily matter in terms of convenience but the more horizontal/vertical edges (parallel to the grid) you got the less artifacts you'll get.. at low resolutions the border pixels will bleed into your shells. You know what I mean.. it takes a lot of resolution to display diagonal lines smoothly (aliasing). Make as much straight as possible, also try to avoid as many seems as you can. Every seem is a possible problem zone.. that's how I see it atleast. Painting this sword in photoshop would be pain in the ...

I don't know the workflow for mudbox but if you get a benefit from painting on the high poly (cavity masking like in zbrush) then you can bake it onto your low poly in whatever resolution you desire just like your normal map.

I also believe you could reduce the mesh even more without losing any detail.
I hope this is useful input for you.

Burpee

Hi !
First thanks for your comments,

i've made a fresh start, with an axe this time, i tried to avoid as many seems as possible

Here's the basemesh



Her's my " high " poly



I baked the map with xNormal

Here's the normal map



But as you can see i have some issues





Is it because of the bad retopo or bad normal map ?

Shurkuris

I would pull the two vertices you have for the blade together so it's 'sharp'.

That looks like bad normals.

Sanislov

If you use smoothing groups, you need to separate the uv layout on these edges. I think that couse the problem.

beta_channel

That looks like you only baked half of the mesh and then mirrored it. Is this the case?

Burpee

Thanks for helping
Nope,
Here's my workflow

- Zbrush Sculpting
- Maya Retopo ( half of the mesh )
- UV Layout for UV Unwrapping
- Back to Maya to Mirroir ( to have mirrored UV am i right ? )
- Then xNormal for baking

beta_channel

Alright, a few things.
How are you importing and exporting from UV layout and Maya? Are your UVs mirrored on your mesh overlapping or are they offset in UV space? Are you resetting your vertex normals after you mirror the object? Are you using a cage in xNormal or explicit projection? Is your image from toolbag? Have you set your tangent space in toolbag to match xNormal? Do you have seam overpaint? What do your UVs look like?

Burpee

al'right

I'm Exporting my UV from UVlayout from an OBJ

Are your UVs mirrored on your mesh overlapping or are they offset in UV space?

They're overlapping i think

Are you resetting your vertex normals after you mirror the object?

I just did, i used soften edge, work better now

Are you using a cage in xNormal or explicit projection?

I'm using default xNormal setting, but i just noticed when i scale my high poly mesh so it " wrap " ( or cage ) my low poly mesh

beta_channel

Alright. A few more things.
-seam overpaint effects all maps, not just your diffuse
-You need to offset your overlapping UVs by 1 in UV space.
-apply mesh smoothing in xnormal to your highpoly to fix your cavity map (I think)
-For an object like that you should really be using 1 of 2 things; either a better cage to support normal maps, or smoothing groups (creased edges) to better support your normal map. You have a lot of really strong normal changes in your blade (yellows and pinks)
-You probably want to learn how to fix that error at the base of your axe other than painting out the error. If you fix it in photoshop you're going to get to do the same fix for every single map that you generate.

Burpee

-seam overpaint effects all maps, not just your diffuse

What do you mean ? should i paint on photoshop over my seems ? On everymap ?

-You need to offset your overlapping UVs by 1 in UV space.

How should i do that ? I'm using Maya


Thanks i'll see what i can do.

beta_channel

http://bit.ly/YIe18Q

You can use the xNormal dilation plugin for overpaint (also known as edge bleed/padding)

Burpee

Yep but i don't understand the purpos of moving my UVs ?

Zarakun

Only the UVs inside the 0-1 space (upper right quarter) have the highpoly details projected on them. If the two sides of your mesh are perfectly symmetrical and on top of each other in this 0-1 space, you try to bake the same thing twice at the same location which will cause you a lot of trouble and baking issues.

That's why you need to move your mirrored pieces 1 unit on the U axis. Since the texture map repeat itself every 1 unit, the mirrored part of the mesh will still get the exact same information as it has now inside the 0-1 space but it won't interfere in your baking process anymore.

Then, for your border issue you should definitely have a look at the wiki for the good practices of normal baking. I don't want to give you false information but from what I know, if you have these 90 degrees angle all around your mesh, you may need to cut your UVs on these edges and harden these edges while keeping other edges smooth.

Finally, using a cage in xnormal is the easiest way to get clean results (if you respected the hard edges rules).

The last possibility is to avoid sharp angles adding bevels to them, smoothing everything and baking things in xnormal with a clean cage.

To sum up if you want to keep sharp edges:

-Harden them and keep other edges smooth

-Cut and separate your UVs everytime you have a hard edge

-Create a cage in Maya (duplicate the lowpoly use the transform tool and move the blue axis to inflate your cage along its vertex normals, usually if your lowpoly match your highpoly you shouldn't have to inflate it too much (in the polyMoveVertex input of the channel box your local translate Z value around 2 - 2.5)

-When you export your LP and it's cage make sure the two files are the same size or it won't work in xnormal.

This should give you a clean normal without any random hand painting editing needed

Hope it helps and go read that wiki everything is there!

Burpee

Thanks my friend

skodone

thank you too will try things at my next bake with a cage!