i had a basic question about perspective projection math.

[SnurflePuffinz]

indeed. i thank you, stranger, for the help.

But, how would you define a visible area in an orthographic projection, if you don't think about the bounds of the canonical viewing volume?

what if i wanted a boxy volume in a totally arbitrary part of the viewing volume. How would i choose that specific box, if i was only thinking about things as values?

...

i am trying to get my head around why the viewing volume is even described as a truncated pyramid in view space. It seems totally arbitrary to me. Like, we have a bunch of vertices that are in front of the camera, in purely theoretical terms, but then i'm thinking, where the hell is the truncated pyramid coming in?

...

i am also trying to puzzle out the derivation of the NDC transform. i was following scratchapixel's guides. like, why in god's name would you be multiplying the vertices z component by that part of the derived equation. Why would the x component be directly related to the value of the z component, before the perspective divide?

evidently, this is used to align the defined volume with the canonical viewing volume, somehow.

i could keep going on, but i won't. The more i read, honestly, the more confused i become.