Does near and far paramaeter affect?

in `blender.py` the near and far parameters are defined as:
```
# bounds, common for all scenes
self.near = 2.0
self.far = 6.0
```
What does this affect?

If I'm training on my own synthetic dataset, in what circumstances do I need to modify these two factors?
Thank you :-)

Start in blender.py at the definitions of self.near and self.far, then trace where these parameters are used in the training or rendering flow. Document what each parameter affects and the circumstances in which someone using a synthetic dataset should change it; the issue is resolved when those questions are answered clearly.

Written by the indexing model from the issue text.