TL;DR:
What is the correct export configuration in Substance Painter to alleviate the need for subsequent output modifications in 3ds Max / Corona---
I have reviewed the available documentation and forum posts describing how to achieve parity between Substance Painter's Iray and realtime viewport with Corona Renderer. Almost all conversation concerning this topic points to Dubcat's
post, which was last updated a little over 2 years ago.
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All exported textures use the following color depth settings:
[TARGET APPEARANCE]
Substance Painter 2018.2.1 - IRay
Substance Painter 2 Corona export preset [rendered in Corona; texture import: Automatic]
Right off the bat, the glossiness is incorrect; never mind the fresnel IOR
Substance Painter 2 Dubcat export preset [rendered in Corona; texture import: Automatic]
I have prepared the material based on what is described in the forum
post. Glossiness is incorrect, reflection color looks incorrect, but may be a function of the fresnel IOR(?) I am certain there is something wrong with the material graph for this shader, but I am unsure what exactly.
Substance Painter 2 Corona export preset [rendered in Corona; texture import: Automatic;
glossiness tweak + IOR map]
Critically, the above material is a layered material. In any realtime renderer (e.g. UE4, Unity, Marmoset), a single shader could be used to accurately render the texture set for each asset; in fact, in UE4 only three textures are required, including a channel packed ORM (occlusion, roughness, metallic) texture. However, in 3ds Max / Corona, seven different textures, including a blend mask, a unique output curve, and two shaders are required to achieve the desired result.
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It is clear that I am misunderstanding something essential about how to achieve parity between Substance Painter and Corona Renderer in terms of export / import settings, color depth, or the like.
Given that glossiness and fresnel tweaks go a long way to recovering the appearance from Substance Painter, the question becomes:
What is the correct export configuration in Substance Painter to alleviate the need for subsequent output modifications in 3ds Max / Corona