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September 29, 2019 at 4:56 pm #2221Jeremy Hill
19.3.0 is up on the builds page.
Sky dome & sun
In this build we add a skyDome and sun, based on the excellent Hošek & Wilkie model. By default, the skyDome node works very simply, rendering a physical sky simulation with sun, based on date, time, and location values built into the node. UTC offset is computed automatically, so all that is required is to choose your desired location and time.
Optionally though, you may explicitly link the skyDome to a sun node, which will override computation of the sun direction, using either the transform of the sun node in the scene, or dateTime and location nodes optionally linked to the sun. When using a sun node, it also becomes possible to alter the size and power output of the sun. This approach of linking a sun node is also the method used to render sun when using colorDome or imageDome.
This build also introduces extensive export for complex IOR materials, through the new complexMaterial and complexLayer nodes. These nodes keep things simple by embedding data for many types commonly used in rendering, and therefore avoid introducing external dependencies (though they also support referencing external files, or even copy/pasting IOR data directly). As should be expected, Bella uses the complexMaterial node to faithfully render complex IOR-based metals, glasses, plastics, crystals, and such.
However, beyond this, the complexLayer also allows layering complex IOR over substrates (whether conductor, dielectric, or complexMaterial), using a configurable virtual thickness. The idea for doing this initially arose from the observation that many complex IOR datasets seem to be measured for thin-film metallic coatings and the like, and that where many such datasets have been fairly useless for rendering in the past, Bella’s thin-layer simulation may be able to make use of these in a way not previously possible (to our knowledge). For a quick example, here is a conductor with thickness-mapped diesel soot IOR layer on the left, and an aluminum complex IOR, with a green soda-lime glass complex IOR layer on the right:
That said, this is being added purely on the theory that given Bella’s physical layer simulation, and the physically-measured IOR data, we may end up with visually-useful results — but to be frank, we cannot really be sure how useful this will end up being, since it really all depends on the data. On the other hand, we also realize that artists never cease to amaze with their ingenuity when given powerful tools, so we have added the functionality on that basis, and we will be curious to see what you are able to do with it.
Though the core Bella material types strive to expose a minimal interface, they are fairly abstract, and it can often take two or more nodes to produce a desired look. As such, we have also been creating a set of “smart” materials, which are simple, concrete types (plastic, ceramic, etc), with just a few parameters each. Though you obviously give up a measure of control by using these, the fact is that in practice, the majority of materials actually used do not require it.
These are just the first examples, and we welcome any input, whether on how these can be improved, or on new types you would like to see implemented, and how. For instance, if you find that you are often constructing a type of material according to a “recipe” where it is just a common set of values or textures that change, it may be that it would be worth encapsulating that recipe in a new material type.
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