When we sample the information in 5D domain, we can use uniform distribution.
But we may not use 5D uniform distribution, but a 3D in the special and 2D in temporal with different sampling rates.
For instance, we are more curious about the pixels changing in the special domain, so add more samples here. But for temporal changing, using grid sampling is also acceptable.
So, we can finally use 3D uniform x 2D grid sampling to render the pixels.
When we sample the information in 5D domain, we can use uniform distribution. But we may not use 5D uniform distribution, but a 3D in the special and 2D in temporal with different sampling rates.
For instance, we are more curious about the pixels changing in the special domain, so add more samples here. But for temporal changing, using grid sampling is also acceptable.
So, we can finally use 3D uniform x 2D grid sampling to render the pixels.