[Paraview] Volume Render Plot - Unreasonable results with vector components or magnitude

[Utkarsh Ayachit]

> There is also another bug or feature of volume rendering: I couldn't make it
> render for all domains, it only renders one domain (for example, when I load
> a CFD study results in EnSight Gold format).

Currently, the volume rendering only supports rendering 1 block in the
multiblock dataset. We're working on a solution that can handle
multiple blocks seamlessly. In the meantime, you can use "Merge
Blocks" filter to merge all blocks into a single block, or use the
"Resample To Image" filter to resample the dataset to a single image
dataset and then volume rendering the result.

Utkarsh