Download

Mesh Distance Fields for large indoor scene

Trying to get my head wrapped around Mesh Distance Fields.
They seem to have several uses and benefits but primarily used to increase the performance and quality of shadows in the far distance for outdoor scenes.

I am lighting a large indoor stadium scene with over 200 Stationary and Static Spotlights, and a Stationary Skylight. Target is Windows desktop only and am using a combination of baked GI and Ray traced Reflections, Shadows.

Would there be any benefit for me to use Mesh Distance Fields?
Also they are referred to as Ray Traced Distance Field Shadows. Does that mean Ray Tracing must be enabled for them to work?

they do not require rtx, its a sort of software raytracing or better said, ray marching through the volume that is created by the sdf.
the mesh distance fields increase memory consumption dependent on the settings that you use (i.e how detailed should the sdf be)
i think the performance gain from switching to sdf is significant but depends on HW

1 Like

Keep in mind that as soon as you turn on Mesh Distance Field Shadows on your lights, your Skeletal Meshes will no longer cast shadows. I leart this the hard way.

Depends one what else you are doing.

If you need materials to detect nearest surfaces for instance, you need distance fields on anyway.

There’s multiple reasons to turn them on and set each mesh to a proper resolution, aside from better lighting.

On older high end cards the distance field shadows far outperform any other type of shadows.

1 Like

Yes its just too bad the ‘whens and whys’ aren’t more fully explored in the documentation.
There also seems to be some advantage in simply enabling Distance Field shadows on your static meshes without explicitly enabling on your lights.

It may be on by default on your skylight maybe?
The docs on dfao were pretty extensive (were because they changed layout again and some links became invalid).

The cost of the shadows is next to none compared to cascade. The downside is it cannot animate.
Skeletal meshes have trouble with it (bypassed by making a shadow only static mesh accompany the skeletal one).

The shorter the range of cascade shadows, the less geometry/tris count to shade, the better the performance at the cost of the scene looking great.

Also, distance fields are required for flow maps for instance. Where rocks and other things can offset the flow of water shaders by their presence on the water.
That’s not something you will even find documented until they release that feature on their own water system thing (though there’s plenty of Brucks talks on it).