Hard-Surface Workflow

purplekami

Hey guys, really simple question here that may seem obvious but I just want to be certain I'm doing things correctly. I'm making a hard-surface model (It's a mech) and my workflow was to make the mid-poly, duplicate, add support loops and then turbosmooth the highpoly.

Now for the low poly should I stitch all the meshes together or can they remain separate? And I would stitch them before baking correct? I'm wondering how to bake the pieces separately if I combine the low poly is essentially the jist of my question. My teacher mentioned that the model has to be airtight if it's to be game-ready.

Thanks in advance!

peanut™

90 % of the time the best way would be to explode the mesh, just tell me if it answers your question here's a quick example:
https://www.youtube.com/watch?v=bgYoXF6QmWw

musashidan

Or if you are baking in either Substance Painter/Designer you don't have to explode as the 'match mesh names' option occludes ray casting on objects that have matching name sets. But it's essentially doing the same thing as explode baking but without the exploding  

Also, I don't know what your teacher told you but the game mesh can be any number of parts. It certainly doesn't have to be 1 contiguous mesh.

peanut™

In Substance there's also an option that models/UV the mesh for you so you dont have to learn anything ...

Quack!

The value of a water-tight mesh is pretty immense at the cost of a bit of time. By making a mesh water-tight you have much less uv waste, you can be more generous with bevels on the low poly to get a nicer  silhouette and better bake, and if you are using a cage, it's generation will be easier. This all comes at the cost of time, welding your low poly to make an water-tight mesh just takes extra resources, if you have them, then it's worth doing. If you don't, then having geo-colliding into other parts is just fine for video games.

As for baking, as Mushashidan suggested, match by mesh name is by far the more efficient than exploding.  I would recommend that also.

purplekami

@peanut™ Thank you for the quick response! That video helped explain exploded baking very clearly. The only main question that remains, I think, is if I have a mesh cut in half to save UV space will it handle symmetry okay or should I use the entire mesh? For example here's the center high poly.

musashidan

peanut™ said:

In Substance there's also an option that models/UV the mesh for you so you dont have to learn anything ...

Even if it means wasting your time learning an obsolete step(provided using SP/SD) in the baking process? There's already enough for people to learn without spending time on an old method that is heading for retirement. Perhaps the OP should also learn how to model by typing cartesian coordinates into a ZX Spectrum......

peanut™

purplekami said:

If I have a mesh cut in half to save UV space will it handle symmetry okay or should I use the entire mesh? For example here's the center high poly.

From my experience, if everything is well UVed symmetry while baking should be preserved, so this way you can save on UV space. If anything reset the cage. (Don't forget to weld your lowpoly accordingly once you mirror the half.)

EarthQuake

You should always bake the full mesh, not delete half of it and bake. The reason is that when you mirror and weld it, you're gonna get seams. This applies to both low and highpoly as well. If you delete half the highpoly, the normals will be incorrect down the center seam.

The only thing special you need to do is offset your lowpoly uvs 1 unit for any overlapping areas to prevent bake errors.

purplekami

EarthQuake said:

You should always bake the full mesh, not delete half of it and bake. The reason is that when you mirror and weld it, you're gonna get seams. This applies to both low and highpoly as well. If you delete half the highpoly, the normals will be incorrect down the center seam.

The only thing special you need to do is offset your lowpoly uvs 1 unit for any overlapping areas to prevent bake errors.

That makes sense, thank you to everybody for the clarifications. I think I'm going to attempt using substance designer to bake the normal maps if that's more efficient, doing exploded bakes can be my back up if for whatever reason the Match Mesh name function doesn't workout (which would surprise me). Almost feels like cheating how useful Substance programs are.