The main purpose for creating a blender add-on was to test out a theory that I had. I wanted test painting specific vertices a specific grayscale value based on a directory of values for isolation in Unreal Engine. The idea was to reduce the amount of material slots down to 1 material slot. I noticed that all of the freely available vehicle models had sometimes 20+ material slots. When you add 40 vehicles in game, you now have theoretically 40*20 = 800 additional draws. Additionally, you now have to keep track of multiple materials and make sure that they are assigned. You could easily end up with a bunch of vehicles with missing materials.

After experimenting with some Python scripting, I realized that I could speed up a lot of processes by turning mundane tasks and operations into a single button press.

Here’s a list of some of the operators/functions:

  • Add Vertices To New Group and Paint: Will add vertices to a new group and paint them specific value.
  • Paint Vertex Color by Group: Will paint selected vertices a a color based on their vertex group.
  • Clear All VP: Basic clear all vertex colors.
  • Parse Materials to VG: Will parse materials based on their name and create a vertex group if name resembles/matches a corresponding item the dataset.
  • Remove VG Groups: Will remove vertex groups only from the category choosen. (vehicle will only remove vehicle groups).
  • Remove All VG: Basic remove all vertex groups.
  • Remove All Materials / Add a Base: Will remove all materials and add a base material (Mi_CharacterMaster, MI_VehicleMaster, MI_BuildingMaster). These materials are the names of the corresponding materials in Unreal. When the asset is imported, the material will automatically apply.
  • Add Custom Properties: Originally to add custom properties based on the vertex value (Currently re-evaluated usefulness for Unreal python operations).
  • Remove All Custom Properties: Basic remove all custom properties.
  • Create Armature: Options to create a basic armature for the specific type of asset.
  • Dump Bone Data: Function to dump bone data.Inset
  • Extrude Poke: Function to perform the inset extrude poke operation.
House model courtesy of:

The image above shows a good overview of the plug in. My focus was to create tools for the main asset types that I typically work with in my projects. Currently there are sections for vehicles, characters, buildings, and a general purpose props. This was my first time creating a blender add-on so I will eventually refactor this into a scalable solution.

Each category has a list of options that are relative to that category. What’s shown in the image above for the building “add vertices to new group and paint” section is a list of typical pieces for a house. When you click on one of the options it will automatically add the vertices that are selected on the model > add them to a vertex group > then ultimately paint them a specific grayscale value. For example here is the data for a building.