Randomly generated characters?

I have a couple of questions surround the generation of unique characters in engine. At the moment I need to understand the high concept processes.

How would I go about spawning randomly generated characters in engine? I understand the concept but I don’t know how to perform it in engine.

For example how would I set up masks to randomize the colour of certain pieces?
How could I set up modular pieces like the torso, head ect then attach those back to something like a bone system?

I cannot help you with modular skeletal meshes.
But this wiki might come useful: A new, community-hosted Unreal Engine Wiki - Announcements - Unreal Engine Forums

For customizable colors, you could do something like this: (this is for each model)

  • Create a texture that define the area where color can be changed. Since a texture has 4 channels, you can have upto 4 custom colorable parts per model. The values range between 0 to 255 for each channel (I usually use 255 for colorable area and 0 for masked area).

  • Create a material like usual. Create 4 Vector4 params (1 for each colorable part).

  • Add the texture we created for this model into the material. Multiply each channel with the corresponding Vector4 param.

  • Add the results of these multiplication togethor (you can have weights and other fancy stuff instead of simple addition).

  • Calculate the diffuse. emissive…as usual.

  • Add the result we got from the addittion to the calculated diffuse.

  • Feed it as the diffuse input for the material.

  • Go ahead a create a material instance from this materil and apply it to your mesh. Now you can change the 4 params from within c++ or blueprint to change the custom color of the parts.

The above method is very basic, but you can extend upton it (for instance custom emissive). I usually use the first 3 channels for custom colors and Alpha channel for emissive.