Model Clean‐up
When you first import model into 3D software out first hurdle will be that for whatever reason its polygons will be split, that is not connected when they seemingly should be. You can usually check which parts are connected to each other by pressing Ctrl+L in Blender (Select > Select Linked)
Pic. Only this part is continuous
And a fix for that is a simple merge. Select All (Hotkey: A) and Merge By Distance (Hotkey: M) or Mesh > Merge > By Distance
But don't do that just yet because...
Polygons oftentimes not only split by also overlapping with their backface, usually on belts, ribbons etc. To visualize that go to Viewport Overlays settings and temporarily enable Face Orientations checkbox
A face normal is a theoretical line, perpendicular to the surface of a polygon. In 3D graphics normals are used to determine the orientation of a polygon face. Game engine then can opt not to draw backfaces, it's called backface culling.
You'll see all polygons change their colors into blue/red/purple-or-pink.
Blue - Forward facing polygons (relative to the camera)
Red - Backface
Purple/Pink - Overlapping polygons, one forward and one backward facing.
Unfortunately, in Blender 4.2+ overlapping polygons no longer shown as purple, it was unintentional behavior.
To flip a polygon, select it and press Alt+N > Flip or (Mesh > Normals > Flip)
Ok why do they even exist? For the record, it's possible to just turn on rendering faces from both sides in material settings in XIV, but game models use these actual overlapping flipped faces instead to paint the underside with a darker color and to have manual control over it, backface culling is a good optimization.
So how do they paint it a darker color? Let's see, turn off Face orientations and switch Blender to Vertex Paint mode.
Pic. Backfaces are painted yellow
Things that are vertex painted yellow will appear darker in-game.
Why? I'm not 100% on this but VertexColor1 translates to
R - AO Multiplier
G - Roughness/Gloss multiplier
B - Specular Multiplier
So when it's yellow the mask is #FFFF00, making specular intensity black or zero
So make a mental note of where your double-sided overlapping faces were, or better yet keep a backup of the original mesh to check back.
And now that you know about backfaces you see why if you'll just merge everything without a little prep you risk ending up with randomly facing polygons, some of them could be painted yellow, some not.
So what I recommend doing is removing backfaces while you're editing the model and restoring them when you're done. Restoring them is very simple, just select forward polygons, duplicate (Shift+D) and Flip (Alt+N>Flip).
Or you could just fix any merge issues (flip stray polys, paint everything back to white)
Ok, now that we dealt with backfaces we can finally MERGE
So you finally merged and now there's a bunch of shading issues on the model.
TLDR what to do:
- Clear Custom Split Normals Data
- Change Auto Smooth Degree to 120
- Select Edges you want to harden and press Edge > Mark Sharp (Hotkey: Ctrl+E). (Another step where having backup of the original will be useful)
To explain what we did more in-depth, shading is based on Vertex Normals, they determine the visual softness or hardness between polygon faces.
- Normally they're auto-computed and kept under the hood, but when we imported the model it contained specific data about where they should point.
And when that's the case then blender sticks to using that data instead of auto-computing. - Then we messed with it by merging
- So we delete that data, it's called Custom Split Normals Data. Blender goes back to auto-computing vertex normals.
- We raise the auto-smoothing threshold to avoid unnecessary hard edges (I think 180deg will be default behavior in blender 4.1)
- We then manually mark edges that should be hard
At least that's a way of dealing with it for gear.
When it comes to body parts it'll be very important to retain those original vertex normals at the seams or sharp transition between parts will be noticeable in-game.
In 3D there two types of polygons used mainly, quads and tris. Quads are preferred because they're easier to work with, deform better and can be predictably subdivided.
Our models imported from the game are in triangles, and even for our purposes sometimes it's advantageous if the model is in quads for a couple of reason.
- It's just easier to add edge loops in places where you need more geometry.
- If you're going to use Smooth brush in sculpting mode it tends to relax the mesh, and quad mesh better retains original edge flow.
So how to restore a model to quads?
Unfortunately there only the bad way and the painful way.
Painful way: Manually select the diagonal edges on the obvious ex-quads and press Del and Dissolve Edge
Bad way: Select a bunch of faces and run Face > Tris to Quads (Hotkey: Alt+J).
Be careful though, this method can do more harm than good by ruining the edge flow when it guesses incorrectly.
Vanilla models are quite low poly, and chances are you'll need more polygons to keep your round forms round. There're several tools to help with that:
- Loop Cut (Hotkey:
Ctrl+R) - Subdividing poly loops - Knife Tool (Hotkey:
Spacebar > K) - Manually splitting polygons - Edge Slide (Hotkey:
G+G) - Sliding the edges/vertices within bounds of existing geometry without warping textures
If you didn't bother with coverting to quads you can still use Edge > Subdivide to add more polygons. But note that this function doesn't smooth anything by itself