Directional light shadows issue with modular meshes

Hi,

In our current project we are creating a small building from modular wall, roof and floor pieces. The building generation is working correctly and is lit fine with HDR but after adding a directional light into the scene and enabling shadows we are seeing light leaks and shadow map artifacts.

The attached screenshots show:

1) The issue with the current full building generator, we’ve changed all the shadow map types (except ESM, we get shader errors in the console when exporting from Maya with ESM and half the meshes don’t load) etc. to test based on the Maya Lighting documentation page but nothing seems to fix it. If ESM is a candidate to get the shadows working then we will investigate the shader error further but I wanted to see what option is best first.

2) I’ve stripped the GLTF file back to only include one type of building (there are 8 types and all their meshes are cloned and hidden on load). This seems to show a different lighting issue as there are now bigger triangles of linear shading happening.

3) A wireframe from the Maya viewport of a couple of example mesh pieces. We use many of these pieces to generate the building by cloning and placing them all and then showing and hiding them based on user input.

4) The settings for the directional light.

Is there a flaw in our workflow or the way we are using the shadows? As this project has so many parts I’m trying to strip it down for testing but it’s taking a while, if you have any questions about the way things are setup please let me know.

Thanks!