Armoured Train [UE4] WIP and Breakdown
greentooth
Hey people
I have (yet another) UE4 project (that will inevitably get mothballed and forgotten in the future) hugely inspired by the behemoth tank in the Battlefield 1 DLC, and BF1's train behemoth itself.
It's been quite a quick turnaround so far, with most of the work shown being done over a long weekend with my place to myself, some peace and quiet. Substance Painter has been a huge help in speeding up mask-making.
I was looking at Soviet and German armoured trains, and figured it would be a neat thing to do, and probably something good to have on my 'folio as making a medium or large scale asset can be a different thing altogether from 90% of props.
So I'm thinking that some people on here, mostly new/aspiring artists, might not have much experience with making large-scale stuff like this. I know I didn't before my first job, so here's something that explains my process with this asset.
First thing I did was whip up a base painted metal material in Substance Designer. I was after something with subtle variation in the albedo, but it needed to remain a light grey to work with colour tinting properly when I got it into Unreal. There's a bit of normal information, faint bumps, dents, scratches, but most of the normal map stuff comes later. And as you'd expect, I made it quite glossy so that I could dirty and rough it up later. It looks like it has super obvious tiling when you see it here, but it seems to work in-engine, so the roughness has dirt/scratches even up close:
To add most of the normal detail, I'm floating quads and strips of quads on top of the main meshes (as a different Material ID) - the material used here is a deferred decal material in UE, affecting Normal and Roughness. So the bolts, welds, etc on the texture appear raised and also aren't quite as shiny as what's underneath. I still have plenty of space on this sheet I can use in the future:
Now what makes the most impact would be the UV2 masks each piece of the train uses. Each segment has a unique unwrap on UV channel 2 (UV1 just supports the tiling painted metal and the trim sheet) that I've used for an AO bake, as well as greyscale masks - 1 for blending between the base metal and a tiling rust, and 1 for adding roughness (as well as a slight brown/orange tint) over the top.
Irritatingly, I don't think there's a way to paint on UV channels other than 1 in Substance Painter, so what I've been doing is just duplicating all my train segments, moving UV2 UVs to UV1, then exporting them out separately just to take into Painter. For actually painting these masks - especially the roughness bland masks - I didn't worry too much about getting them too neat, I just made sure there was variation and things like drips/leaks that would have a significant visual impact when it's all in the Unreal Material. Painter is also what I used to bake the UV2 AO - I just used a copy of the exported mesh as the "High Poly".
Here's an example of the roughness UV2 mask for the largest carriage of my train:
I'd recommend channel-packing masks like these to make Tech Artists like you, as they're just black and white maps.
And finally, here's how my Max scene looks as of right now - you can see my multi-material in action, with the first material being a checker so all the parts that use the tiling painted metal have the same density, another for seeing the trim sheet details, etc. My decal sheet texture isn't showing up on this PC, but those floating grey squares are where the signage/painted decals are. There are still some unique-unwrapped assets in grey that I have yet to finish up, but those are just made as normal props and placed at appropriate points along the train asset:
Hope this helps someone
This sort of process can work pretty well for lots of larger assets, vehicles, etc. Sorry this has been half Showcase, half Tech Talk
I have (yet another) UE4 project (that will inevitably get mothballed and forgotten in the future) hugely inspired by the behemoth tank in the Battlefield 1 DLC, and BF1's train behemoth itself.
It's been quite a quick turnaround so far, with most of the work shown being done over a long weekend with my place to myself, some peace and quiet. Substance Painter has been a huge help in speeding up mask-making.
I was looking at Soviet and German armoured trains, and figured it would be a neat thing to do, and probably something good to have on my 'folio as making a medium or large scale asset can be a different thing altogether from 90% of props.
WIP Art:
ArtStation link: <a rel="nofollow" href="https://www.artstation.com/artwork/WVRnJ"><b>https://www.artstation.com/artwork/WVRnJ</b></a>
Mini-Breakdown:
So I'm thinking that some people on here, mostly new/aspiring artists, might not have much experience with making large-scale stuff like this. I know I didn't before my first job, so here's something that explains my process with this asset.
First thing I did was whip up a base painted metal material in Substance Designer. I was after something with subtle variation in the albedo, but it needed to remain a light grey to work with colour tinting properly when I got it into Unreal. There's a bit of normal information, faint bumps, dents, scratches, but most of the normal map stuff comes later. And as you'd expect, I made it quite glossy so that I could dirty and rough it up later. It looks like it has super obvious tiling when you see it here, but it seems to work in-engine, so the roughness has dirt/scratches even up close:
To add most of the normal detail, I'm floating quads and strips of quads on top of the main meshes (as a different Material ID) - the material used here is a deferred decal material in UE, affecting Normal and Roughness. So the bolts, welds, etc on the texture appear raised and also aren't quite as shiny as what's underneath. I still have plenty of space on this sheet I can use in the future:
Now what makes the most impact would be the UV2 masks each piece of the train uses. Each segment has a unique unwrap on UV channel 2 (UV1 just supports the tiling painted metal and the trim sheet) that I've used for an AO bake, as well as greyscale masks - 1 for blending between the base metal and a tiling rust, and 1 for adding roughness (as well as a slight brown/orange tint) over the top.
Irritatingly, I don't think there's a way to paint on UV channels other than 1 in Substance Painter, so what I've been doing is just duplicating all my train segments, moving UV2 UVs to UV1, then exporting them out separately just to take into Painter. For actually painting these masks - especially the roughness bland masks - I didn't worry too much about getting them too neat, I just made sure there was variation and things like drips/leaks that would have a significant visual impact when it's all in the Unreal Material. Painter is also what I used to bake the UV2 AO - I just used a copy of the exported mesh as the "High Poly".
Here's an example of the roughness UV2 mask for the largest carriage of my train:
I'd recommend channel-packing masks like these to make Tech Artists like you, as they're just black and white maps.
And finally, here's how my Max scene looks as of right now - you can see my multi-material in action, with the first material being a checker so all the parts that use the tiling painted metal have the same density, another for seeing the trim sheet details, etc. My decal sheet texture isn't showing up on this PC, but those floating grey squares are where the signage/painted decals are. There are still some unique-unwrapped assets in grey that I have yet to finish up, but those are just made as normal props and placed at appropriate points along the train asset:
Hope this helps someone
This sort of process can work pretty well for lots of larger assets, vehicles, etc. Sorry this has been half Showcase, half Tech Talk
Replies
I have some additional questions just to clear things up for me a little!
So in short, you basically use a tilable material on the main mesh, which has some floating planes above it to add decals like the seams and bolts?
I have never worked with UV2s, so this is basically a new UV channel, and you can use UE4 to access it and blend it between the additional roughness you created? How would you set it up in the material editor?
Wouldn't it be easier to just use vertex painting to blend between a "clean" and a "worn" version in the material? Or did you use UV2s because you had some additional resolution to work with?
I have some experience in the CryEngine, and I never knew that something like this would be even possible. Is this somesort of a UE4-exclusive?
Once again, thank you for this post, I hope my questions aren't too nooby!
-Crimi
Essentially yep, just tiling textures with floating polygons, and the details (buffers, weapons, etc) are just gonna be standard props. The trick is to approach something this scale in almost the same way you should approach texturing (and material-ing) and environment - good materials, blending to add interest and hide the tiling, then dress with detail, decals, and props on top. UE has the Texture Coordinates ("TexCoord") node which lets you select the "Coordinate Index" (UV Channel) you want to use, then plug that into the texture(s).
This method definitely isn't Unreal-exclusive. It's pretty close to how Star Citizen achieve their superb results on large ships in Lumberyard (previously CryEngine). You can do the same thing with vertex painting - especially if you mask the transition with a nice mask texture - but that requires more geometry than I wanted to use, and I prefer working with masks personally.
(although I am also using the red vertex colour channel to darken my main material near the bottom of the meshes)
The roughness blending in my material is pretty simple. While I use a Lerp to blend between painted metal and rust, for roughness I just add the UV2 mask to the base roughness, and as I paint my roughness in white, the grime/leaks/etc I paint in Substance Painter become rougher areas in Unreal.
I'm blending between the base roughness (glossy) and the rust roughness (almost 100% rough), then just adding my mask's white values over the top
That clears things up then. As I thought, you used the mask instead of the Vertex Painting to get the additional resolution, because, of course, for vertex painting it's important to have enough vertices for detailed painting.
Yes! I actually read a LOT about the techniques in Star Citizen! And I read they use vertex painting, and no 2nd UV channel to break up the obvious tiling. And I have never done big environments before.
Anyways, that clears things up. Thank you for your time, I really love learning things with breakdowns like that, especially because I only created some props, and no big environment.
That trick with darkening the lower part using vertex painting is pretty clever too!
Thank you once again!
- Crimi
What resolution are you using for the roughness map in UV2?
Also, if I understood it correctly you're using a tiling rust texture and using a mask in UV2 to show it in areas?
Yup, the base painted metal has a tiling set of textures for plain, and another for rusted. The rust shows up in any areas that are white in the UV2 rust mask via a simple Lerp.
Latest Update - new lighting and PP, more things are textured:
I've added some interesting (I hope) details via meshes with UV1 normal & ao maps (AO is also affecting Roughness in the Material) and UV2 for the same tiling, tinted painted metal:
Latest shots:
Adding some wooden munitions crates on one of the back carriages: