I used the starter content's wall objects, an atmospheric fog, a directional light and this is the result:

enter image description here

As you can see, it's obvious where the new object starts.


  • \$\begingroup\$ What version of the Unreal engine are you using? And I know it's a silly question but have you rebuilt the lighting? \$\endgroup\$
    – Stephen
    Nov 22, 2018 at 11:18

1 Answer 1


Answering as of 4.21.1, one reason for problems with fluid lighting may be due to issues with UV maps of model. Check if:

  • UV map present or not.
  • Any faces overlapping in UV map


In this image:

  • Upper Left: No UV, light placed in editor
  • Upper Right: No UV, after building lighting
  • Lower Left: Non overlapping UV, light placed in editor
  • Lower Right: Non overlapping UV, lighting built

Lights are static 2cd intensity, 300 attenuation, enough to cover a single building. Materials are default material.

Good Luck.

Thank you Mr. Gregory for reminding about overlapping UV case. So, in case of overlapping UV, we get jagged lighting like this.


  • New Left: Overlapping UV, light placed in editor
  • New Right: Overlapping UV, lighting built

Ideally, we dont want corners to be lit up. Most low poly textures have baked ambient lighting which is least costly. If you absolutely want dynamic lighting, use ambient occlusion and proper texture/normal maps to remove corner effects.

Should look like this:

enter image description here

  • Upper part: In engine Ambient Occlusion 0.0
  • Lower part: In engine Ambient Occlusion 1.0

More customization(for low poly lighting) available if you make texture not light using by custom greyscale map from 3d modelling software.

  • \$\begingroup\$ Can you also show what the symptoms of an overlapping UV face might look like? That would cover the gamut of possible causes you've described. \$\endgroup\$
    – DMGregory
    Jan 6, 2019 at 15:10

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .