Hello. I’m creating a night, future city scene, lit by a lot of neons, holograms etc. When the light falls onto tiling, modular ground meshes, lightmap seams are visible. In the examples from my scene, the road on the left catches more of the red light, and the road on the right catches more yellow, and the transition is not smooth.
It doesn’t seem to be a lightmap UVs issue, as everything is OK without emissive lighting. Is it a bug, am I missing something? I would like to avoid faking this with actual lights place on each “hologram”, unless there would be some advantage to it.
Here is the problem recreated using an empty scene and basic models, and then screenshots from my actual scene, lit and unlit.
File → New Level → Default
Alt-drag the floor object with grid snapping set to 100, so that there are 2 adjacent pieces.
Create a material with a Constant3Vector set to a bright color, multiplied by 8, linked to the emissive input. Duplicate with a different color.
Drag a basic cube onto the floor object, scale it up, set first material, alt-drag a second cube onto the second floor object, set second material.
Turn on the “Use Emissive for Static Lighting” parameter of both cubes.
As a workaround, I just created a wider road mesh, but I knew the problem would reappear sooner or later, like where two meshes touch on a road intersection. And even on a modular sidewalk, where each piece has lowered edges, meaning there’s a little groove which hides the place where those pieces touch, the uneveneness of lighting is still visible when I zoom out. Here’s an example in Lighting Only view mode.
In the actual scene, I have a lightmass volume covering the scene. Also tried higher lightmap resolution, lighting quality and scalability settings.
Thank you! Just changing the scale seems to have solved it (although the building process takes a bit longer, as it warns in the tooltip for this option). Also thanks for those two links, they seem to have many pages worth of information, I’ll be sure to dig into them.
