Premature Evaluation: Poly Bridge

Every week, Rob Zacny crosses the chasm of Early Access to find a treat on the other side. Sometimes the path across is perilous, sometimes it is as sturdy as a horizontal oak.

As something rolls across a painstakingly-constructed series of spans and supports in Dry Cactus' Poly Bridge [official site], you can see the structural elements changing color as load is added or subtracted and they draw closer to their failure point. A car followed by a heavy bus turns a set of struts and arches from a cheerful green to a neutral yellow to a wary orange to a bloody red, and it's right at that moment the excitement of civil engineering comes to life.

If that piece can just hold, and the car rolls onto the other half of the span with its added supports and pillars, then you've done your job and built a useful bridge. Alternately, the piece will wobble, collapse, and dump your passengers and a good part of your bridge into a canyon or a river.

That's not the troubling part. The troubling part is when I watch one of my bridges just barely survive its loading and unloading, where I can visibly observe the structure trembling on the verge of failure. Then it holds and I get the option to move on to a new bridge-building challenge or modify my structure, and I think, "Boy, that bridge is barely holding it together. But it's under-budget, and it did its job, so let's move on." It's at the exact moment that I conclude my, "Good enough!" calculation that I think about all the bridges I cross every day near my house, or on the long drive back to my family's home at the holidays.

How many, I wonder, exist in that red zone under their full legal load? How many are just a bad cable or rivet away from dumping me into a river or ravine, just for the sake of saving a few grand in construction costs?

With 58,000 bridges in the United States in need of repairs and rated structurally deficient, it's not something I like to think about. Yet Poly Bridge delights me, even as it puts me in charge of one impending engineering disaster after another, forcing me to think about all the forces trying to knock a bridge right out from under a car, and all the work required to overcome those forces.

I've always considered engineering to be a rather dry subject matter, but Poly Bridge makes it all relatively effortless and fun to get into. Pieces snap together with satisfying physicality that reminds me of World of Goo, and the aesthetic isn't that far removed from a Road Runner cartoon. A (slightly grating) bluegrassy playlist gives the whole thing a relaxed atmosphere that's more reminiscent of a backyard cookout than a math and physics test.

Still, while it's easy to start slapping together joints beams in Poly Bridge, it requires a bit more precision that it might let on at first. A latticework of support beams leading down to a single pillar in the middle of a span requires some pretty exact angles in order to deliver the load at the right place, at the right angle. Eventually, I was pretty glad that Poly Bridge includes a subtle graphing-paper backdrop that you can use as you move pieces around. The difference between 60 degrees and 70 isn't easy to eyeball in isolation, but it's easy to see the effects of a misjudged angle as an elegant substructure turns into a groaning mass of redundant pieces and excess weight.

Most of the time I didn't need to be too obsessive about the details of my designs, but the more challenging the terrain and the more efficient you want to be, the more you need to sweat those details. Also, if I'm being honest, it's pretty annoying to try and build a fairly standard truss bridge that I've seen a million time in my life, and end up with something that looks like it came out of a Doctor Seuss book.

I spent most of my time playing the campaign challenges, which are probably the most appealing part of Poly Bridge for someone like me. In the campaign, you're given a series of scenarios with different requirements and geographic features to take into account. Maybe your bridge needs to have clearance for large ships to travel the waterway below, or maybe it needs to climb to a much higher elevation on the other side of a canyon. Sometimes you'll have stable rock below to anchor support pillars, while in other places you'll have to span a wide river with almost all the support anchored on either shore. Sometimes, you just need to build a ramp so that a car or bike can go Evel Knievel-ing across a gorge.

It's a good way to learn the various types of bridges you can build, and the tools available to build them. However, at this stage I do feel like it could be slightly more effectively tutorialized. While the basic tutorial does a good job at teaching you simple truss bridge and raised bridges, it doesn't take long for the campaign to introduce new bridges and materials that it hasn't done much to explain. Figuring out how and where to build supports for a suspension bridge took me out of the game and down a long Google and Wikipedia rabbit hole.

That's not necessarily a bad thing, and it's pretty cool to play a game that simulates that kind of curiosity, but it also made for some frustrating trial-and-error, since building even a bad bridge can take quite a lot of effort.

In the campaign, each challenge also has a given budget, so you can't just cover the entire thing in reinforcements and steel pillars and brute-force your way across a gap. More materials cost money, so the challenges encourage solutions that are not only effective but elegant. Or in my case, solutions that are just barely functional but meet the design parameters.

The sandbox mode is a little more for pure-creation, engineering-for-engineering's sake play. It's less interesting to me, but it enables people to create and share additional challenges via Steam Workshop. Right now I feel like most of the challenges I'm finding are a little too hardcore or trollish for my taste ("build a bridge to catch a car dropped from a great height, and then launch it via ramp across a huge chasm"), but I expect over time there will be a few campaigns' worth of good challenges readily available.

If I have a reservation about Poly Bridge, it's that I do wonder how interesting bridge-building can get before there's nothing to do but seek out Rube Goldberg challenges. Once you've mastered a couple types of suspension bridge, is building a longer or more efficient one all that interesting? If greater efficiency is what will drive players to keep going, I do wonder if that begins to run up against the limitation of Poly Bridge's fairly easygoing interface, which doesn't make precision easy.

That's a hypothetical problem for me at the moment. Right now I've got a gorge to cross with enough clearance for a steamship, and no appropriate anchors anywhere along the way, and not enough material to build the suspension bridge I want. When I've mastered that, and bunch of other challenges, we'll see how Poly Bridge holds up. For now, I'm just having too much fun learning how bridges work, and how to build better ones for myself.

Poly Bridge is available on Steam for a sound, lightly-loaded £8.99 / $11.99. My impressions are based on build 1021999 on 12 April 2016.