Baking a Mess - xNormal/Baking workflow Help & Advice
polycounter lvl 10
Hi Everyone!
As part of getting myself up outta the dirt in 2015, I am getting my bake on. Previously I haven't done much in the way of high to low baking; it's a weakness in my current skillset that I aim to rectify ASAP.
So I made myself a really basic asset (an axe) in Zbrush, retopo'ed it in 3DS Max*, UV'ed the low poly and sent 'em both to xNormal for some baking. It was a mess. The edges of the axe head in particular were the problem.
So I have gone and made two unwraps of the axe head to do some tests:
The soft edge UV just splits down the middle, from where the blade edge runs, to the holes where the shaft fits in (tee hee). It is the way I would of unwrapped had I just been hand painting/making a texture to fit the low poly mesh without a high poly bake. The whole thing is one smoothing group.
The hard edge UV I made using what I think is the hard surface modelling way, where I break the UV at the edges of the geo where we get 90 degree angles and what have you. I broke each UV island into it's own smoothing group for this.
I haven't delved deep enough into Hard Surface techniques and UVs, so I am no expert in this arena, but that is why I did this little test so I had a small, easy asset to work this stuff out on.
I exported both of 'em outta Max with these OBJ settings:
The put them both through xNormal following a few different guides. I am unsure if the issues I am having may be due to a poor bake/poor knowledge of xNormal on my behalf, but currently I think it must be something to do with my meshes/unwraps. Anyway, results of the normal bakes applied as textures are here:
1.> Correct me if I've got the wrong end of the stick here, but I thought that by giving each UV island it's own smoothing group, and breaking along hard edges was supposed to make this kind of thing NOT happen.
2.> I've seen this before when making blade edges that are low poly, but never really found a fix... can anyone explain exactly what causes this issue? It seems like a slightly different problem to 1.
3.> Once again, please correct me if I'm wrong but this is part of the problem of not breaking the UV seams of a hard surface object along the edge, isn't it? You get this incorrect bending/shading when approaching edges that have the normal map stretched across them.
I dropped each mesh into 3DO, to see what they look like in an engine with the normal maps applied, and a metal textures, and in the end the soft UV worked out much better:
Hard UV
The edges look all kindsa wrong...
Soft UV
Looks almost perfect... other than just some of my crappy hi-poly mesh coming through and the faint UV seam down the middle. The only other issue I see is that "blade edge" problem I highlighted in 2. up above.
I will update this thread as I move forward with this asset, but it will be a rather quick thing. I want to move onto my next, more complex asset: Marston's Sawed off Shotgun from Red Dead Redemption.
I am just hoping by documenting this, anyone who has the time can spot any errors or problems I might be making. Anyway, thanks to all of you who took the time to read this wall of text, and if you got any C&C or just advice, it would be much appreciated!
Cheers
Jarv
As part of getting myself up outta the dirt in 2015, I am getting my bake on. Previously I haven't done much in the way of high to low baking; it's a weakness in my current skillset that I aim to rectify ASAP.
So I made myself a really basic asset (an axe) in Zbrush, retopo'ed it in 3DS Max*, UV'ed the low poly and sent 'em both to xNormal for some baking. It was a mess. The edges of the axe head in particular were the problem.
*[I think I will find a different tool for that job, Max seems a bit fiddly. 3D Coat will be used on my next retopo task.]
So I have gone and made two unwraps of the axe head to do some tests:
The soft edge UV just splits down the middle, from where the blade edge runs, to the holes where the shaft fits in (tee hee). It is the way I would of unwrapped had I just been hand painting/making a texture to fit the low poly mesh without a high poly bake. The whole thing is one smoothing group.
The hard edge UV I made using what I think is the hard surface modelling way, where I break the UV at the edges of the geo where we get 90 degree angles and what have you. I broke each UV island into it's own smoothing group for this.
I haven't delved deep enough into Hard Surface techniques and UVs, so I am no expert in this arena, but that is why I did this little test so I had a small, easy asset to work this stuff out on.
I exported both of 'em outta Max with these OBJ settings:
The put them both through xNormal following a few different guides. I am unsure if the issues I am having may be due to a poor bake/poor knowledge of xNormal on my behalf, but currently I think it must be something to do with my meshes/unwraps. Anyway, results of the normal bakes applied as textures are here:
1.> Correct me if I've got the wrong end of the stick here, but I thought that by giving each UV island it's own smoothing group, and breaking along hard edges was supposed to make this kind of thing NOT happen.
Might this be because my Hi Poly geo isn't "hard" enough? It's not a sharp edge, it was made to look sort of hand hammered, so it's a somewhat gentle edge.
2.> I've seen this before when making blade edges that are low poly, but never really found a fix... can anyone explain exactly what causes this issue? It seems like a slightly different problem to 1.
3.> Once again, please correct me if I'm wrong but this is part of the problem of not breaking the UV seams of a hard surface object along the edge, isn't it? You get this incorrect bending/shading when approaching edges that have the normal map stretched across them.
I dropped each mesh into 3DO, to see what they look like in an engine with the normal maps applied, and a metal textures, and in the end the soft UV worked out much better:
Hard UV
The edges look all kindsa wrong...
Soft UV
Looks almost perfect... other than just some of my crappy hi-poly mesh coming through and the faint UV seam down the middle. The only other issue I see is that "blade edge" problem I highlighted in 2. up above.
I will update this thread as I move forward with this asset, but it will be a rather quick thing. I want to move onto my next, more complex asset: Marston's Sawed off Shotgun from Red Dead Redemption.
I am just hoping by documenting this, anyone who has the time can spot any errors or problems I might be making. Anyway, thanks to all of you who took the time to read this wall of text, and if you got any C&C or just advice, it would be much appreciated!
Cheers
Jarv
Replies
Apply it as a normal map, as it should be, and check that it looks the way you want it.
Your example where you say the big greenish patch at the edge of your blade (on the soft edge mesh) is ugly/wrong... that's actually how the normal map should look for that bit of the mesh - the bake is perfectly correct.
Also, the default xNormal tangent basis is not synced to 3DS Max's tangent basis. So anything you bake in xNormal that uses that isn't going to look 100% right in Max anyway. You're always best to bake for your target engine and test that the result is correct inside of the target engine.
I would stick to the soft edge mesh here, as there's no real benefit that's going to come from using hard edges. Your point about 3 is correct, however. You must have a UV seam (and a bit of a gap for some padding) wherever you have a hard edge (but the reverse is not true; A UV seam doesn't need a hard edge but a hard edge does need a UV seam).