Today I stumbled across the concept of using environment / HDRI textures to light a scene. I have some questions about it:
aside from the fact that env textures are static and so do not support dynamic lighting or shadow casting, are there any other disadvantages to relying on them primarily to light a scene?
from what I’ve read so far, it seems to me that the effect of environment textures could be compared to ambient lighting, with the difference that env textures support different intensity lighting depending on the angle that light is emitted/bounced off. Is this a reasonable thing to think or am I wildly off-base?
It is kind of a nice comparison for the diffuse part but you also have the specular one creating nice reflections in your scenes. Basically a fully glossy metallic object would almost fully reflect the “environment” You can basically think of it as a 3d photo surrounding your object where every pixel is used as a light.
Ambient lighting won’t generally participate very much in your material’s light characteristics, as it’s indirect. An environment texture, as @sebavan mentions, gives every pixel of the background a light value which can then be used by a Physically-Based Rendering material (PBR) to calculate the various lighting factors (specular, diffuse, etc.) in a close approximation of how the light would behave in a real-world scene.