Factory – pt 1

This blog post won’t mostly be about a factory, but if I title it this way, it might encourage me to finish something at home for a change 😉

My wife had a great idea that I should re-make some of my older art assets, so I’m going to have a crack at this one, that I made for Heroes Over Europe, 8 years ago:

I was quite happy with this, back in the day. I’d had quite a lot of misses with texturing on that project. The jump from 32*32 texture sheets on a PS2 flight game to 512*512 texture sets was something that took a lot of adjusting to.

I was pretty happy with the amount of detail I managed to squeeze out of a single 512 set for this guy, although I had to do some fairly creative unwrapping to make it happen, so it wasn’t a very optimal asset for rendering!

The plan

I want to make a UE4 scene set at the base of a similar building.
The main technical goal is to learn to use Substance Painter better, and to finally get back to doing some environment art.

Paving the way in Houdini

First up, I wanted to have a go at making a tiling brick material in Substance Painter.
I’ve used it a bit on and off, in game jams, etc, but haven’t had much chance to dig into it.

Now… This is where a sensible artist would jump into a tool like ZBrush, and throw together a tiling high poly mesh.

But, in order to score decently on Technical Director Buzz Word Bingo, I needed to be able to say the word Procedural at least a dozen more times this week, so…

I made bricks #Procedurally in Houdini, huzzah!

I was originally planning to use Substance Designer, which I’ve been playing around with on and off since Splinter Cell: Blacklist, but I didn’t want to take the time to learn it properly right now. The next plan was Modo replicators (which are awesome), but I ran into a few issues with displacement.

Making bricks

Here is the network for making my brick variations, and I’ll explain a few of the less obvious bits of it:

It a little lame, but my brick is a subdivided block with some noise on it:

I didn’t want to wait for ages for every brick to have unique noise, so the “UniqueBrickCopy” node creates 8 unique IDs, which are passed into my Noise Attribute VOP, and used to offset the position for two of the noise nodes I’m using on vertex position, as you can see bottom left here:

So that the repetition isn’t obvious, I randomly flip the Y and Z of the brick, so even if you get the same brick twice in a row, there’s less chance of a repeat (that’s what the random_y_180 and random_z_180 nodes are at the start of this section).

Under those flipping nodes, there are some other nodes for random rotations, scale and transform to give some variation.

Randomness

Each position in my larger tiling pattern has a unique ID, so that I can apply the same ID to two different brick placements, and know that I’m going to have the exact same brick (to make sure it tiles when I bake it out).

You can see the unique IDs as the random colours in the first shot of the bricks back up near the top.

You might notice (if you squint) that the top two and bottom two rows, and left two and 2nd and 3rd from the right rows have matching random colours.

Placing the bricks in a pattern

There was a fair bit of manual back and forth to get this working, so it’s not very re-usable, but I created two offset grids, copied a brick onto each point of the grid, and played around with brick scale and grid offsets until the pattern worked.

So each grid creates an “orientation” attribute, which is what rotates the bricks for the alternating rows. I merge the points together, sort them along the X and Y axis (so the the vertex numbers go up across rows).

Now, the only interesting bit here is creating the unique instance ID I mentioned before.
Since I’ve sorted the vertices, I set the ID to be the vertex ID, but I want to make sure that the last two columns and the last two rows match with the first and last columns and rows.

This is where the two wrangle nodes come in: they just check if the vertex is in the last two columns, and if it is, set the ID to be back at the start of the row.

So then we have this (sorry, bit hard to read, but pretend that the point IDs on the right match those on the left):

And yes, in case you are wondering, this is a lot of effort for something that could be easier done in ZBrush.
I’m not in the habit of forcing things down slow procedural paths when there is no benefit in doing so, but in this case: kittens!
(I’ve got to break my own rules sometimes for the sake of fun at home :))

Painter time

Great, all of that ugly #Procedural(tm) stuff out of the way, now on to Substance Painter!

So I’ve brought in the high poly from Houdini, and baked it out onto a mesh, and this is my starting point.
I’m not going to break down everything I’ve done in Substance, but here are the layers:

All of the layers are #Procedural(tm), using the inbuilt masks and generators in Painter, which use the curvature, ambient occlusion and thickness maps that Painter generates from your high poly mesh.

The only layer that had any manual input was the black patches, because I manually picked a bunch of IDs from my Houdini ID texture bake, to get a nice distribution:

The only reason I picked so many manually is that Painter seems to have some issues with edge pixels in a Surface ID map, so I had to try and not pick edge bricks.
Otherwise, I could have picked a lot less, and ramped the tolerance up more.

You might notice that the material is a little dark. I still haven’t nailed getting my UE4 lighting setup to match with Substance, so that’s something I need to work on.
Luckily, it’s pretty easy to go back and lighten it up without losing any quality 🙂

Testing in UE4

Pretty happy with that, should look ok with some mesh variation, concrete skirting, etc!
I’ll still need to spend more time balancing brightness, etc.

For giggles, I brought in my wet material shader from this scene:

https://geofflester.wordpress.com/2015/03/22/rising-damp/

Not sure if I’ll be having a wet scene or not yet, but it does add some variation, so I might keep it 🙂

Oh, and in case you were wondering how I generated the vertex colour mask for the water puddles… #Procedural(tm)!

Exported out of Houdini, a bunch of noise, etc. You get the idea 🙂

Next up

Think I’ll do some vegetation scattering on the puddle plane in Houdini, bake out the distribution to vertex colours, and use it to drive some material stuff in UE4 (moss/dirt under the plants, etc).

And probably export the plants out as a few different unique models, and their positions to something that UE4 can read.

That’s the current plan, anyway 🙂