3D Level Design: Adding Emissions to Texture Maps

Intro

In this article, I will cover how to add emissions to texture maps. Emissions allow you to an emissive light to the material that will light surrounding object (if it is static).

Exporting Texture Map

The first thing we need to do is to see if the texture map needs to be altered.

Going to the game object and looking at the materials, we can set the Emission true or see there is no Emission Map.

The whole game object is set to Emission and we only want the green tube section.

Looking at the texture map, we can see the areas of green we need to create the emission map for.

We will find the texture map in the Finder or Explore

and importing it into your photo editing software. I will be using Photoshop in this example.

Creating an Emission Map

When imported into Photoshop, the green areas are already transparent so we want to be able to select this are.

In the Select window, we can load a selection layer.

In this case we want to the select the Transparency layer which will be all of the areas that are not transparent. If we Invert it, we can select all the areas that are Transparent.

If the area wasn’t already transparent, we would have to use the selection tools to isolate those green areas that we want to make emissive.

But, we have those transparent areas selected so lets create a new layer with it.

Once we have this new layer, we are going to fill in the transparent with a grey color so we can adjust it in Unity.

We want to make sure those areas are 100% filled in.

This area is where the Emission will come through, but we need to black out the areas we do not want to be emissive.

We Duplicate the Emissive Layer and order it behind the Emissive Layer. Select the remain area and fill it with Black.

It is ready to be exported.

Exporting Emission Texture Map

We will “Save a Copy…” which allows us to save it as a PNG. It needs to be a PNG.

We append the name with _Emissions and save it to the tex file of the game object in the Unity project folder.

The Emission texture map will be automatically imported into the Unity project since we saved the PNG file into the project file.

We will go back to the game objects material options and drag the new Emission texture map to the Emission Map.

We can see how just the green area is now emissive and not the whole object.

From here we can set the color and intensity to the desired levels.

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