Why did you use neural networks? There are faster techniques in analytical geometry that can extract surface contours from color gradients from images, and they do this faster and directly.
2) We don't extract surface contours, we learn a volumetric radiance field! To oversimplify, we learn a (smooth) function that, given a position in space, produces the differential opacity and color at that space. To render an image from a camera viewpoint, we approximately integrate along rays emitted from each pixel of the camera.
Check out NeRF and our paper to learn more about this representation!
One of the best non-classical methods is this one (https://grail.cs.washington.edu/projects/sq_rome_g1/), and our method is significantly improves upon it. We do not compare directly with it, but Neural Rerendering in the Wild does, and we improve upon it.
also they're way higher quality than traditional techniques