Corona 7 was released last year with some interesting new features, but the developers are not slacking off in 2022. Corona 8 is already planned for release in the first quarter of 2022. There are three new major features, plus one extra material parameter. The new decal object, slicer material, and a new scatterer called 'Chaos Scatter.' There are also two minor additions in Corona 8, a tall parameter added to the physical material and a feature to randomize texture map coordinates by polygon.
Let's jump into the fray with the new decal object. To create one, you just need to go to the 'create' tab, select 'geometry,' then 'Corona,' and pick the 'CDecal' object type. The new object will appear as a bounding box in the viewport. Using this object, you can apply any material and project it onto any surface in the scene based on the bounding box limits.
For example, we can apply a simple material to the decal object, and everything that's within the object's bounding box will have the decal's material applied. If you go into the interactive rendering, you can see that the doughnut is projected everywhere from top to bottom of this car, no matter the material underneath.
In the object's options, there are a few useful features. You can change the masking, taking the opacity from the applied material or a custom map. You can control the bump and displacement by replacing the ones on the decal material. You can also control the depth limit of the decal, limit the angle to which it's applied or blur the projected material. One last useful feature is that you can exclude objects from the decal's effect. Such as if I wanted the decal to affect only the car body and not the road.
In the manhole cover below, you can see how the decal can affect the underlying material's displacement. The manhole on the left has the original displacement from the asphalt material, while the one on the right had it replaced with the one coming from the decal material.
Slicer is a new type of material in Corona that will slice through everything in the scene when applied to an object. You will find it in the material editor as a separate node under the Corona tab. Let's have a closer look at how the material woIf we apply the slicer material to a box, you can see it indiscriminately slices through all the objects. You can control what's sliced and exclude objects from the material options. You can cap the slice with a material or leave it open. One cool feature is that you can apply a custom material to the slice capping. What's even better is that it's working pretty much flawlessly with complex shapes and can work great as a lightweight material-based boolean.
If we apply the slicer material to a box, you can see it indiscriminately slices through all the objects. You can control what's sliced and exclude objects from the material options. You can cap the slice with a material or leave it open. One cool feature is that you can apply a custom material to the slice capping. What's even better is that it's working pretty much flawlessly with complex shapes and can work great as a lightweight material-based boolean.
We generated this effect by slicing the objects with an animated blob shape and applying a gold material to the slice caps. Apart from abstract uses, this material's most apparent use case would be to slice an architectural scene and create a perspective floor plan. Overall, it might come in handy for many architectural visualization artists.
Next, let's check the new UVW randomization mode for texturing. This mode is available for CoronaMultiMap and CoronaUvwRandomizer nodes. Here's an example using the CoronaMultiMap node with a variety of texture maps loaded.
Let's say we want to distribute all the maps on each particular polygon on those objects in the background. This wouldn't be possible with the previous modes, but now if we change to 'polygon' mode, each polygon is applied a random texture tile. Just as in the past, we can also add additional hue or gamma randomization to pronounce the effect. Additionally, we can do the same with the CoronaUvwRandomizer node to randomly distribute the same roughness or bump map across each polygon.
Chaos Scatter is a rebuilt version of the current Corona Scatter with some new and highly requested features available. It's still a long way from taking over Forest Pack as a complex scattering tool, but it seems to be going in the right direction. One significant difference is that the Chaos Scatter is now a separate tool, so the first thing you would need to do to get it running would be to run the supplied installer for your 3ds Max version. Then in 3ds Max, you can find it in the 'geometry' tab, under 'Chaos,' labeled ChaosScatter.
The first new thing is support for excluding and including splines. If you assign a spline to 'spline includes,' it will limit the distribution to that spline area. And the other way round, splines added to 'spline exclude' will remove objects from beneath the selected splines. You could also change the projection from the Z-axis to any axis.
And the distribution will follow the target splines even when animated. One thing to consider, though, is that if you want to avoid random seed per frame, you will need to turn on 'temporal consistency' to freeze the distribution on the frame you choose.
Also new, you can now distribute objects based on geometry slope. You can set the distribution to cover only a particular slope angle. It's obviously pretty useful for distributing plants in an environment, but as you can see, you can use it in a lot of different ways.
One last major feature in the recent daily build is that you can use a surface color map for your distribution. This one is available in a different menu, in the 'Chaos' tab under ChaosScatterSurfaceColor. You can use it in the diffuse slot, just plug it into the distributed objects' material and switch to using the custom bitmap. You can also control hue and gamma randomization, and Chaos will apply it to the whole distribution.
Tail is a minor addition to the Corona physical material. It's an additional parameter that you can find in the advanced options under 'base tail,' which can go between zero and one.
The idea behind the tail parameter is that it will only blur reflections in the reflection peak, the parts around the fringe of the object. The effect is subtle unless you bump the value above 0.8 or mix it with roughness values above 0. What's nice about the tail parameter is that you can generate sharp reflections but taper this effect as the reflection peaks around the object's edge.
Here you can see the comparison of how tail relates to roughness. With roughness, you get a consistent reflection diffusion. But with tail, you get a smoothed-out reflection while the convex detail outside the reflection peak will still render quite sharp reflections.
In short, Corona 8 is already shaping up to be a fantastic release for artists no matter what kind of art you’re creating. The new material types and options increase flexibility and the new Chaos Scatter is a big step forward as an integrated scattering tool.
If you use Corona in your workflow, then be sure to check out our Corona render farm. We provide fully automated rendering with 24/7 support and we will be adding support for Corona 8 soon! I hope you’ve enjoyed this introduction to the new features coming to Corona. Don’t forget to let us know your favorite new feature down in the comments.