Considering rain, some questions

[snacktimeParticipant]

First question, how easy is it to use the core ai/behavior tree system without having it control movement, animations, etc? All of our ai is server side, and it just needs to function as a brain and send data to the clients. Our character controllers all take input from classes derived from a common interface where we abstract local/remote commands that control movement and other actions. When it comes to controlling characters and interacting with the environment, our approaches are usually somewhat different just because of the scale we are working at.

I’m also curious about the navigation system. Is it navmesh based,grid based, hybrid? Our primary challenge for navigation is that our maps are huge, on average around 80 terrains 1000×1000. Unity’s navigation is a non starter here. recastnavigation works fine performance wise, but is a pain to extend.

[primeKeymaster]

It isn’t particularly difficult to just use the behavior tree system for decision making. You can replace any of RAIN’s basic elements with your own versions. If you don’t want movement and navigation to happen, then just create no-op standins. Or, you could create network standins that communicate commands rather than moving the AI directly.

RAIN’s navigation system is a navmesh generated by code based on Recast. Of course, so is Unity’s, Aron Granberg’s etc. Each has their unique quirks and advantages. 1000 x 1000 isn’t a problem in any of those systems (depending on your recast cell size resolution).

[snacktimeParticipant]

You misunderstood we have 80 terrains on average per scene, which is why I asked. We load/unload terrains in range dynamically as the player moves around. I’m very familiar with recastnavigation, and not all implementations are created equal. Unity’s navmesh like I said is a non starter, it won’t even bake our terrains without running out of memory most of the time. And since it doesn’t allow multiple navmeshes per scene, we can’t just bake each terrain individually.

[primeKeymaster]

Understood. There aren’t any hard limits on how many NavMeshes can be used with RAIN. You could certainly precompute the Navmeshes in RAIN and keep the NavMesh object attached to the associated Terrain. You just want to make sure that the navmeshes overlap some (if the AI will be wandering between them) or at least that “Allow Off Graph Movement” is enabled. You also want to make sure the the Navmeshes are being properly registered and unregistered as the terrains come and go.

There shouldn’t be any problem getting your terrains to bake with RAIN. There are plenty of options to get it to work if you have difficulty (increasing the cell size, working with the grid size, etc.

[snacktimeParticipant]

Got a chance to play around with the navmesh stuff. I like it. It generates fast, I can create as many nav meshes as I want. Not quite as many features as Unity but overall just better designed api and easier to work with.

I also spent some time playing with behavior trees and the ai stuff. It’s also nicely done but the strong focus on less experienced developers was making it more difficult to use. I wanted to know how to use the libraries directly and skip all of the ui, as a ui just slows me down basically. I absolutely hate the convention in the Unity community of having video tutorials for everything, as it usually takes away from actual documentation, and for experienced developers just slows down the whole learning process. Give me a solid library of usage examples on github any day.

Not so much a gripe about RAIN per say, I understand why it’s this way given the target audience. But it left me having a difficult time imagining what using RAIN would look like without all of the visual stuff, and that is essentially the question I’m still asking myself. When you strip away all the visuals, what is the real value. Probably half of what RAIN does I have already, like an integrated entity-component system and existing movemement/animation controllers, etc.. Most any professional game is going to already have some of what RAIN does to one degree or another. On the other hand RAIN is still interesting because of how it pulls a lot of the pieces together.

I haven’t actually made a decision on whether to use RAIN yet, just thought I’d give my impressions after an evening of playing around with it.

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