OT: Renderer Comparison

Gordig

I present to you a comparison of the three render engines I've been experimenting with in C4D. I am very far from an expert in rendering or texturing, so take whatever I say with a grain of salt.

Shot 1: Cycles 4D
This was my original engine, and I've had to move on because it's become unusable on my system for reasons that are as yet unclear. Because I couldn't use it to render beyond a certain point, it's also a less developed version of the shot with fewer kinks worked out.
Pros: Great at procedural textures and most flexible in terms of displacement because displacement isn't directly tied to mesh density. The road definitely looks best in this version, and to reach this level of detail with Octane or Arnold would have required a very dense mesh, where I could use a completely undivided mesh in Cycles. It's good for skins, and it's also by far the easiest to use with X-Particles because it can shade the particle simulations directly, rather than requiring the simulations to be cached as VDBs. Insydium also provides a wealth of shader presets with the Fused subscription, so you have a lot of pre-made shaders to use. Cycles has the most flexible options for altering the colors of texture maps, where I struggled a bit with Octane and Arnold to accomplish the same things I was able to do easily using Cycles.
Cons: Some of the presets are built in ways that are a bit too complex for my tastes, and I felt like I didn't have as much control over, for example, the fire as I would have wanted because it was hard to identify which part of the complex node system would make the change I was after. It also colors any object with missing texture maps or incompatible shaders an obnoxious bright pink, which I can understand from the perspective of identifying things that need to be fixed, but is still annoying.

Shot 2: Octane
Pros: Probably the easiest to use, and a good all-around renderer. Even if I never rendered in Octane again, I'd definitely keep my subscription if only for the free monthly KitBash3D set (most of the architecture in this shot comes from the Shangri-La set).
Cons: I had the most trouble getting displacement to work well at all, and it seems to pretty ill-equipped to make procedural textures. I'm not in love with the way a lot of the operators worked, and even in the node editor, you seem pretty limited on what you can actually do. I watched a few tutorials on how to make good skin in Octane, and even the makers of those tutorials seemed to think that Octane wasn't the best option for skin, and I agree with that. I had a shockingly hard time figuring out how to make transparent materials work, and it seems like that should be one of the simplest things to do. Octane's out-of-core rendering system seems like a great feature until you really try to use it, and on a complex scene like this, I would reach points where it just wouldn't render any more. I did eventually figure out how to increase out-of-core memory, but it's an annoying limitation, especially considering that Cycles and Arnold don't require a GPU at all.

Shot 3: Arnold
Pros: Very good for skins, incredible for hair (though this shot doesn't show it off very well). For my money, Arnold is the most realistic of the three renderers being compared, and also the most cinematic looking. Very flexible, comparable to Cycles in that respect.
Cons: I don't know what the experience of using Arnold in 3DS Max or Maya is like, but the integration into C4D is pretty bad. There's absolutely no ability to use texture maps that are already in the scene, so EVERY SINGLE IMAGE must be loaded through file explorer. If, like me, you like to use absolute paths for textures instead of saving them with the scene, that means that converting shaders to Arnold requires a whole lot of digging through directories to get everything moved over. I definitely would have preferred Autodesk develop their own GUI for Arnold rather than using a modified version of XPresso. The Arnold volume object refused to work properly in this scene, so I couldn't really affect the size, position or orientation of the simulation. This definitely isn't a limitation of the object itself, because it worked as expected in a new scene; it just refused to work in this scene for unclear reasons, so I had to use C4D's native volume loader. Fewer options are available for controlling samples for different render elements when rendering with GPU versus CPU, which makes absolutely no sense to me. The Arnold Parameters tag adds a lot of useful functionality, but it's becoming apparent that you need to apply it to almost everything, so I wonder if more of the functionality could have been incorporated into the shading system instead. There's also an exceptionally irritating quirk where the picture viewer will only render whatever is currently selected, so you have to remember to unselect everything before you render. If there's a way to disable this behavior, I haven't found it.

I also gave Corona a shot, but I hate it, so don't expect a full breakdown.