Unity 3D – Fix lights that shine on a single mesh only

This is a short post. It is short because it presents a very simple solution. However, it is a solution to a problem that took me two days to solve.

As I do not want you to lose the same time as I did, I will describe the problem in a few sentences. I will state the keywords below, just to make sure you find this post if you have the same problem … I couldn’t find the solution myself in any forum, I found out by having some luck 🙂 And it is so simple….

The problem:

When you use multiple meshes that are connected to each other, e.g. for modulair walls, or if you use multiple point lights, you might end up with an annoying effect: not all meshes get the same amount of light. The image below demonstrates this. It is a screenshot from a scene in Unity, presenting two identical walls, with two identical lights. There is not any other light source in the scene. Take a look at the difference in lighting:

Different light effect on identical meshes

A more real-world example can be seen in the image below:

Different light effect on identical meshes #2

The walls are simple quads, with the same (seamless) texture applied to it. The scene has multiple lights.

How to solve this? It is very simple! Simply go to the lights that shine or should shine on the wall or that should somehow affect your wall. Next, in the inspector set the Render mode to Important.

That’s it! Check the image below:

Lighting fixed by setting the light sources render mode to important

Problem Solved! … took me two days experimenting with textures, different meshes, shading, smoothness … the solution was build into Unity all the time 🙂

Keywords: Unity 3D Light, Bug, Light Error, same light different effect, light interference, light shows seams, light shines differently on multiple objects.

Do you like the scene with the tables? You can get it here:


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