I decided to try out Corona Renderer and see how it compares to V-Ray in terms of quality and speed. Below are the renders using V-Ray’s different GI methods and I tried the progressive sampler of which until reccently I didn’t know off. The last but not least is the Corona render. These are all raw renders converted to 8 bit and rendered at 1920 x 1080 on i7 2600 with 16 GB of RAM.
Irradiance map + light cache materials have higher subdiv values than Brute force GI method and latter in Adaptive image sampler Color threshold is 0.014, Adaptive DMC min, max 1/10 compared to 0.03, 1/12. Irradiance map + light cache has little more red in the shadows then Brute force GI + light cache, because Brute force method was rendered with different camera white balance so I matched it using Photoshop.
Irradiance map + light cache method using progressive sampler is very good and even gives cleaner render and it took 2 hours and 28 mins compared to 6 hours and 37 mins.
Corona using progressive importance sampling has the same render time as Irradiance map Light Cache progressive sampler so you can see the difference.
In Corona I converted V-Ray materials using Corona Converter script that is installed with the main Corona plugin into the 3dsmax scripts directory. Then I added Corona render elements and optimized materials of wall and chair by the pool because in Albedo render pass they were shown in red, which meant that the brightness was too high and that can cause problems such as washed out look and excessive render times. Here you can read more about Albedo https://coronarenderer.freshdesk.com/support/solutions/articles/5000515614-what-is-albedo-
In my case the material preview was not showing the diffuse so I replaced color correction node with color correct node. I had a issue with alpha in leaf materials. The issue was with Turkish pine provided in Laubwerk Plants Kit Freebie which was fixed with the latest Laubwerk Player for 3ds Max update.
I think Corona is very good and the price is very affordable. I really like how much effort Chaos takes in improving V-Ray and progressive sampling is amazing because I can see general render quite quickly and the results are very good. Not to mention that all feature of V-Ray work with progressive sampling.
Hope you find this post informative. Let me know what you think.