Nvidia Research Turns 2D Photos into 3D Scenes

Post by crubier » Sat, Mar 26, 2022, 1:05 PM UTC

sorenjan wrote: post #44

I don't really understand why NeRFs would be particularly useful in more than a few niche cases, perhaps because I don't fully understand what they really are. My impression is that you take a bunch of photos in various places and directions, then you use those as samples of a 3D function that describes the full scene, and optimize a neural network to minimize the difference between the true light field and what's de…

Post by ghgr » Sat, Mar 26, 2022, 1:39 PM UTC

Mandelmus wrote: post #184

CobrastanJorji wrote: post #157

Earlier quoted context omitted.

That's more interesting than I realized. In this example, I assumed that the model was generating some sort of 3D mesh representing the woman. Is that not at all the case? Would this technique be unable to generate a model or volumetric information despite being able to reasonably render her from many directions?

No, there is no mesh. A NeRF is a neural network trained to work as a function f(x, y, z, θ, φ). You put in your viewing position (x, y, z) in 3D space and the direction (θ, φ) you're looking into (where θ and φ are the angles for up/down and left/right, respectively), and the function will output a tuple (r, g, b, σ) of the colour (r, g, b) and the material density (σ) of whatever you see at the pixel in that direct…

Post by Chris2048 » Sat, Mar 26, 2022, 2:22 PM UTC

ineedasername wrote: post #62

olladecarne wrote: post #46

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There's so many things we invent with good intentions but in the end go terribly wrong and I think this is one of those things. I think it's ok to mourn and remember the past, but moving on and accepting reality is important to a healthy life. Let's be real though, the startup that makes this but appeals to our worst instincts make bank. I can't imagine how much more messed up future generations will be as we keep ma…

"mourn and move on" is a somewhat Western concept of dealing with death. Plenty of cultures around the world have developed different practices, up to religious forms of ancestor worship.

Post by ravenstine » Sat, Mar 26, 2022, 2:24 PM UTC

chrstphrknwtn wrote: post #163

Jach wrote: post #109

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Don't knock it til you try it? I mean, already in recent years people have made some very low fidelity 'resurrections' and gotten some measure of comfort from it, never mind the many years of history of people who visit gravestones to 'chat' (some even believing they get replies to some extent or another). When markov chains were hip, "talk with Charles Dickens!" (play with a markov model trained on his works) was at…

I suppose... but I'll always know that it's some sort of cheap trick to make me think they're still here when really their consciousness ceased. Will the simulacrum age? Will it change? Will it ever surprise me or intrigue me? And if it does, is it something the dead person truly would have done? It's sort of like a photograph; a photograph seems to capture reality but all it shows is some abstraction of a physical r…

Post by Chris2048 » Sat, Mar 26, 2022, 2:30 PM UTC

dtgriscom wrote: post #208

lowdest wrote: post #47

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>Imagine living a quadrillion years. Even as a god, that would be miserable. This seems very subjective, I don't agree at all.

In Ursula Le Guin's book "Changing Planes", there's a story called "The Island of the Immortals." Spoiler alert: living forever is no fun.