The logic behind the system

Before starting working on the actual blueprints, I made a clear list of things that I’m gonna need to make it work:

• a footprint opacity map for each foot
• a footprint normal for each foot
• deferred decal materials for each foot using the dbuffer translucent normal blending mode
• blueprints for each feet that uses a decal component with the materials created before

The process

Textures and Materials

I went through a trial and error process trying to find the best footprint textures for the task. Here’s some of the ones I tried.

In the end I went with this one.

Then I proceeded to set up the materials like so:

Blueprints

The first blueprint I made is using a decal component that has the footstep material in the allocated spot. I made one for each foot.

Next up, inside the ThridPersonCharacter blueprint, I added two plane components (these are going to display our decal). I parented them to the character mesh (CharacterMesh0) by dragging them under it, and added parent sockets to each of them, foot_l for the left foot plane, foot_r for the right foot plane.

After that, I headed over to Mannequin>Animations>ThirdPersonRun to set a couple notifies when the foot touches the ground in the animation. I’m going to use these later on in the ThirdPersonAnimation blueprint.

I can now go back to my ThirdPersonCharacter blueprint event graph to set up a couple custom events. I start by making a SpawnFootprintL event that spawns an actor from my BP_Left_Footprint (the decal component blueprint that contains the material). I then drag and drop a reference to my Foot L plane that I set up at the base of my character’s foot, in order to be able to track its location.

Initially, I thought the rotation of the footprint should be that of the plane, but thanks to this tutorial I found out that it should actually just be the actor rotation.

I then went ahead and copy-pasted the code from the left foot and changed the reference and the class for the right foot (BP_Right_Footprint).

Now that that’s set up, I headed over to the ThirdPersonAnimation blueprint event graph. The logic here is that I want the footprints to spawn only when the feet touch the ground. I do that by getting an Event Blueprint Begin Play that’s casted to the ThirdPesonCharacter and an AnimNotify event for each foot. What this will do is esentially, every time the animation notify I previously set up in the run animation is called, it will trigger the custom events I just set up inside the ThirdPersonCharacter blueprint and spawn a footstep.

Phew, that was a lot. Surprisingly, when I hit play, everything worked accordingly. All I needed to do now was to adjust the sizes of the decal blueprints to match the size of the player’s foot. That took a bit of playing around, but in the end I got it to match pretty well.

Hope you enjoyed my little (not so little) tutorial. It was a long process, but thankfully google is a thing nowadays.

Resources I haven’t previously mentioned:

Normal map only footprints - this is where I got the idea to use a DBuffer Decal blending mode instead of translucent.

Unreal Engine 4 - Deforming Snow Tutorial - this was just general inspiration, I didn’t end up doing this