Projecting occupancy grid sampled points back to image space

[YiftachEde]

Hi! i'm attempting to use nerfacc with pixelnerf, and for that usage, i want to be able to first, generate an occupancy grid of a general scene, and then, sample points on it and project them back to an image space. i'm finding it difficult understanding how to best project those points to get the appropriate points in the images planes. is there any guide on what transformation occurs when the points are "squished" to be in the aabb region?

Thanks!