We have tested for you: Corona 4 for 3ds Max and C4D

Caustics at last!
Even though Corona made it possible for artists to create among the most beautiful images of the past few years, caustics were missing for certain views. Reflective and refractive caustics are calculated but also, more difficult for pathtracer, at the bottom of a pool (caustics seen through transparent material).  To be noticed: caustics also work with the LightMix. Caustics are an option within Corona. You must activate them in the material and in the renderer. Thus you can target your materials. So of course, the image becomes more realistic but also requires more calculation and rendering durations increase significantly. You need to remain vigilant if you want to stay in the standards we know with Corona.

A new denoiser
The list grows bigger with the arrival of the Intel denoiser (open image denoise). It’s the one I use and I find it very qualitative. It’s less reactive than the Nvidia one but the image you get can be used for intermediate presentations. Indeed, Corona places it between the Nvidia one and their own denoiser. It also has the great advantage to work with any CPU.

One render, several environments
That’s something new that I find very interesting: the possibility to have several setups of sun/environement in your scene that you can then activate in the LightMix. This new feature enables to place several suns and environments or even different HDRI, render everything at the same time and then select them individually post-prod. Congratulations! It is less “bling bling” than the caustics but it is focused on production.

Materials and textures switch in 1 click (for 3ds Max)
A “small feature” (I guess, from a development point of view) totally production oriented. Corona select map and Corona select material make it easy to create various textures and / or materials set ups for one scene. Very useful to switch in a click from concrete floor to wooden floor or test different furniture veneers in a kitchen. You can also use Corona map select to quickly change HDR in an environment. It’s almost my favorite new feature considering the productivity gain it allows. Next step: automatisation to launch the rendering of a set up pack?

Object selection and focus in the interactive rendering
It is not my favorite feature but it is true that being able to do the lens focusing by clicking in the image is quick and convenient. I don't use the object selection in the rendering window that much. This feature already exists in other renderers. Is it just a trend or are we shifting towards this for lighting and shading ? 

Let's finish by noticing the appearance of a fisheye camera lens and the fixing of a disturbing bug when several OpenVDBs (like clouds for instance) overlapped. 
With caustics, Corona 4 adds a must-have feature for any renderer. The integration is convincing to me. Of course, the price to pay is longer rendering durations. The new denoiser, multi-environment and new nodes (for 3ds Max) are the most interesting features to me. They show that the development team remains focused on customers' needs.  

Christophe Bicchierai

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