Corona is a big player in the ArchViz industry. It is safe to say that almost every artist has heard of Corona or used it at some point. The reason being, it's very good. I have known about Corona for years, but never given it much of a try until now, making it the third renderer I have used for ArchViz after VRay and FStorm. So, here are some of my thoughts on it in comparison to my favourite renderer at the moment, FStorm.
Obviously, this will come down to your PC specs. For reference, I have an i7 7700K, 32GB of RAM and a GTX 1080Ti. My GPU is definitely more powerful than my CPU, also costing about double the price, so it is expected that GPU rendering would be faster on my PC than CPU rendering. But still, I feel this is still important.
Corona is pretty fast, especially using the interactive mode which gives you results very quickly and allows you to make changes as needed. The majority of my time spent rendering, is for doing test renders, so this is important. Final rendering time is also important, but in my opinion, less important since it doesn't affect my day to day work. In my experience, FStorm is simply faster at everything. With a better CPU, perhaps I would see less of a difference, but from my testing, FStorm is able to generate a high quality render in seconds and a final quality, low noise image, often in under an hour, if not 15-30 minutes depending on the scene. If speed was my only goal, I would have to go with FStorm. Another thing being that I can simply add more and more GPU's to improve my rendering speed, something that isn't really possible with Corona since it is a CPU renderer. Adding more than one CPU requires a special motherboard and anything beyond two is going to be difficult and very expensive. With GPU rendering though, you could have 2 or more GPU's in your desktop PC without the need for a separate render farm.
In short, I found Corona to be quick, but not as quick as FStorm. If time is not an issue or you have the power of multiple CPU's, it is capable of producing an image in very little time. Not to mention it has a built in denoiser, something that FStorm does not have.
Quality is very subjective. I personally find that FStorm is able to produce a very realistic render with very little tweaking to the lighting, materials or render settings. This could also be down to the fact that I am much more comfortable in FStorm than any other renderer. In Corona, I found myself struggling a little bit to achieve the desired results. I think what it comes down to is tone mapping. I've read many posts about FStorm having the best tone mapping out there and I believe it to be true. It is able to give very photographic results, very easily. Corona on the other hand might make you work a little more to do the same thing.
I found that once I did get comfortable with Corona, the results were very nice, giving a very sharp and clean result with satisfying highlights and shadows. With some renderers, it can be difficult to create a bright image without overexposing parts or completely losing any contrast. But Corona handles this very well, which is one of the reasons it is so popular with ArchViz.
I prefer certain things about FStorm materials and the UI, but overall, Corona is better at this. The one thing that won me over was the displacement. I always found FStorm displacement was lacking and often gives unwanted results. Corona on the other hand does this perfectly. Using displacement is easy, plus it's quick. It's so nice to be able to plug in a displacement map and have it work exactly how you want it.
Corona materials are a bit more complex than FStorm, but I do like the options it provides and the fact that it works with the default maps in 3DS Max. I prefer some of the FStorm maps and controllers, especially the FStorm colour correction node. But overall, Corona materials are easy to understand and manipulate, with lots of options and a lot of control. Corona also has a good material converter built in, though it doesn't work with FStorm. Since most of my models are either VRay or Corona, this isn't a big issue.
I've talked about this a little bit already, but in my opinion, FStorm is much more simple than any other renderer I have personally used. It just works, with very little tweaking required. Corona is also very simple though. There's no need to go searching through the settings to try and improve your image as the default settings just work. In terms of simplicity, it comes very close to FStorm but with more options for everything from materials to render settings. It's nice that Corona gives you these options, but FStorm is still very new and doesn't have a team behind it.
'In conclusion, I think Corona is a fantastic render engine. It's able to give very good results, very easily and quickly. It does almost everything quite well when it comes to ArchViz and is widely supported which is even nicer. It doesn't have the speed that FStorm has, at least not for a single workstation PC, but it is not slow by any means. I love the materials in Corona, especially how great the displacement works and with very little effort.
Whether I will be getting a monthly subscription to Corona, I'm not sure, but I am excited to use more. I think it will only get better and better and its very much built with ArchViz in mind, which is great for people like me. It's very stable and I found it much easier than VRay. I think that everyone who works in ArchViz should get familiar with Corona and give it a try. Plus, the they offer a 45 day trial of the full software which is really nice. Corona has a great team behind it with exciting new features coming out all the time. FStorm will be my go to renderer for the near future, but I like what Corona offers and having more options is always good. I plan on using it more in the coming weeks as I spend more time on studies and learning new skills so I can be proficient in more software.
Be sure to check out my Instagram, where I post almost every render I make, including studies that don't quite make it into my portfolio. I'll be using Corona a lot more now and posting the results as I improve. Thanks for reading!