[Paraview-developers] Manta plugin in TPD mode?

[David E DeMarle]

>> 1) shadows, reflections and refractions are incorrect with parallel
>> server side rendering
>
> Ouch.
>
> Is this true in all rendering situations, I mean, is the rendering of
> shadows and such fundamentally broken?

When you are rendering on a single node it isn't a problem. And you
can render with multiple threads on that node if it has multiple
cores.

But yes in distributed memory parallel it is fundamentally broken.
Paraview is data parallel, where the data is divided amongst
processors. Secondary rays on any given processor miss then when they
should actually hit some other processor's data. You are left then
with images that are not much better quality than standard
rasterization for big data. There are solutions to this in the
literature (communicate rays or communicate data) but are costly and
not trivial to implement.