Applying Normal Map to Wheels

Olly89

So I'm pretty comfortable with normal baking, but can never seem to get a good look for wheels. I can't seem to narrow down the problem to my UV's, smoothing groups  or maybe just the fact that the bake is too ambitious. A picture says a thousand words so here's the high poly and low poly respectively. Grab the Max scene here if you want to look yourself. I'm using Substance Painter to bake. Thanks in advance.

gnoop

You need to set smooth groups first  and edit  vertex normals so the shading gradients would be within bevels mostly

Revel

Hmm..you didn't assign any turbosmooth modifier to your HP model. Also if you want to bake in SP2, you need to collapse the turbosmooth modifier before export it, if not SP2 will ignore your modifier stack from max.

Olly89

gnoop: I'll research vertex normals a bit more and see what I get, thanks.
Revel: There was originally a turbosmooth modifier on it but I collapsed it already.

Olly89

Right two days of research I still can't get it right. I've even remodelled the whole thing but still getting nowhere near a decent bake. I wouldn't normally ask this directly for help, but it's the last normal bake I need to do for this train scene I made (where I've used normal maps all over the place with no issues). It's just these damn wheels. New wheel scene here (HP and LP) on google drive. Stack hasn't been collapsed so you can see exactly what I've done. 

Synaesthesia

I made those exact trucks you're using and didn't have any issues with the bake, but I use MightyBake instead. Could you save this scene out as a 2016 file so I can take a look at it for you?

Olly89

Wow nice model. How many polys is that? Yeah, I've baked the rest, it's just the wheels left. 2016 version here.

Synaesthesia

Each truck is 57,000 polygons. The scene I'm using it in is in my signature: Florida Megascans UE4 environment. I'm a train guy, feel free to ask me if you ever need help with railroad modeling or texturing.

Regarding your model, this is what I see in Max:



Is this correct? If it isn't, could you collapse your stack before saving the file and/or kick out a FBX of the high and low contained in the same file?

Olly89

Hm nope that's not it. This is for export to UE4 so a lot less polys, think the whole scene is around 20k. But stacks collapsed file is here. And individual files are wheel here, and HP here. Thanks for the help.

Synaesthesia

Alright, so this works properly. I've taken a look at your model and adjusted the UVs a bit. Here's before:



After:



You've got duplicate faces on the model that need vertices welded, just as a QC check.



It looks like your issue stems from simply not having enough geometry to support the silhouette of the shape. This is with MightyBake's rounded normals projecting furthest to try and capture everything. My advice would be to add more geo to the shape to closer match the high-poly. When I Flow Connect to add geo to the surfaces, your low-poly becomes apparently oval shaped - so you'll want to rebuild the low to match the high a bit closer. Otherwise, this is all I can see that's wrong with it.



I've attached the files I edited so you can take a look at how I adjusted your model: http://www.filedropper.com/trainwheel

Not pictured is the adjustment I made to the ring of your UVs on the strip surrounding the front face of the wheel. It was laid out oddly so I cut it and flattened it out so it would bake better. 

From a purely aesthetic and functionality viewpoint, I've never seen a wheel with that flange attached to it. You might want to consider removing it. Train wheels generally only have a flange on the outside ring rather than a flange on both the inside and out.

Olly89

Damn that's more help than I expected, really appreciated. It's late here (UK), but I'll rework the model tomorrow with your advice. Thanks again.

Olly89

Right so I've tweaked the UVS as you suggested, also welded those extra vertices and increased the resolution of the low poly (below). I then baked with xNormal and imported into your fine program.

Low Poly:


This is the render.

Looks pretty good, but did expect less 'waviness' around the edges. Any way to reduce that?

EDIT: Did manage to remove most of the waviness, but had to increase the LP polys again to 386. Much cleaner result though.

Synaesthesia

That's a really good result. Definitely closer to what it looks like your original intent was.

I'd love to see this project when it's done - regardless of what tool you decide to use when you paint it. Could you shoot me a message on Facebook?

Olly89

No Facebook but sure I'll send you a message on here. Thanks again for the help.