Ray traced soft shadows problem!

I have a skyscraper(Building) in my game and i want to enable “Ray-traced soft shadows” but i get very ugly resolution problems even with the quality set to 100.0, I get these problems because my
building mesh is too big! I was recommended two options,

    • Divide your building mesh into more modular pieces and enable RTSS(Ray-traced soft shadows) on each part (which would solve my problem) but inflicts another problem (see below)
    • Increase the “RTSS” resolution volume manually in the source code.

Now with solution 1, it would take me 40 X longer if i was to divide my mesh into 40 parts, and that’s a problem when i have hundreds of large assets!.
With solution 2, Unfortunately there is absolutely no documentation. So i’m asking (you) the forums to see if there are any other options or solutions to my situation. Thanks for considering my question :smiley:

Hello AndrewM47,

Thank you for your post. I am attempting to replicate your issue, but I am having a bit of trouble. In order to narrow down some of the possibilities I was hoping that you could answer a few questions.

  1. What version of the engine are you using?
  2. could you possibly provide a screenshot that would show what you are referring to when you say " very ugly resolution problems.
  3. Would you mind including a screenshot with any settings that you have changed in order for me to make sure that I am setting up my reproduction scenario as close as possible to yours.

Thanks,

I am using 4.7.2 but this problem has been occurring since 4.6.1,

Hi ,

You’ll want to break the model into smaller chunks to use effectively with Distance Fields. They do not work well for larger meshes.

I also see that Daniel provided a more in-depth answer as well:

I’m afraid you’re out of luck,
there’s just no way to represent huge
objects with distance fields in volume
textures as the memory needed is
unreasonable. Internally a single mesh
is limited to 128^3 resolution (4mb)
and the entire atlas is limited to
512^3 (256mb). The 128 clamp is in
MeshUtilities.cpp somewhere (don’t
have the code in front of me). Even if
you raised it, at best you would get a
x2 or x4 increase in resolution which
is not going to make huge objects
work.

One thing you can do to handle huge
objects is to use ‘Far’ cascades that
are coming in 4.8. These are cascaded
shadow maps that only include
Landscape and other static meshes
tagged as bFarShadow. These can be
pretty efficient with proper LOD. In
the open world GDC demo we used the
far cascades for huge rocks and
Landscape. RTDF shadows are only for
trees + medium rocks.

Also, take a look at the documentation for DFAO and RTDFSS with regards to the limitations. The limitations listed in both are not specific to either, but to DFs as a whole.