Hi! I’m new to Unreal Engine, I want to build 3D characters from scratch—especially a robot—with rigging that I can later use for movement/animation (e.g., hooking up movement animations, setting up the skeleton, etc.)
Could someone explain what tools/workflow I should use, and the overall process for building the character? For example:
how to design the 3D character, should I break the character the into movable parts?
how to set up nodes for limbs and a rig/skeleton
how to handle rigid vs flexible parts (so some body sections stay solid and don’t twist)
If there are any recommended resources or best practices, I’d really appreciate them.
Setting up a character from scratch is quite the task, you usually break it down into different stages, or what’s called a pipeline. Let’s cover the overall process, step by step, and I will add a few resources for each one:
First, the character design, your robot. Start with a drawing, try to keep it very simple, as it’s your first attempt. And as you mentioned, breaking it into movable parts is a great approach. It doesn’t matter if your first model is made of cubes, you will improve with each iteration, and practice. For modelling the character, I would suggest using Blender, as it’s free, and there are hundreds of resources to learn. I will leave you a good example for a simple robot (I would try to add a regular set of legs, though):
Now that you have a model, the next step is to setup it’s rig/skeleton, which can be done in Blender as well, using an Armature. Just add bones following the distribution of your movable parts, give it enough articulations to be close to a human-like character, while keeping the parts themselves rigid using weight skin, as it’s still a robot character. Here’s another video guide for this stage:
Next, take your mesh and skeleton, and export them from Blender to Unreal, following these parameters for FBX files:
Make sure that Armature and Mesh are checked
Set “Apply Scalings” to FBX Units Scale
Look for “Add Leaf Bones” and turn it off
Once inside UE5, drag your files into content browse, to get the import window
Make sure all relevant “Import” checks are enabled (mesh, skeleton, etc)
End result should be a Skeletal Mesh asset, a Skeleton asset, and a Physics Asset
Finally, animation in UE, which is an entire subject on it’s own. I recommend following the control rig UE doc to learn how to manipulate your character, as well as the video course below for Sequencer. You can also experiment using the engine’s default character, Manny, which has lots of animations already designed for it in FAB:
Not to rain on your parade, but you are asking for a way to explain something that would normally take about 1000 pages of a small print book in a forum post…
The best answer I can give you is: “just do it” (no, Nike didn’t pay me).
It takes about 3 years of hands-on learning to go from 0 to a finished character via trial and error. You can shorten the time dramatically by taking classes and following some learning courses.
Let’s assume you want a robot like you mentioned. Metal doesnt really bend (well spring steel would but let’s excude that for simpleness).
Normally, anything that doesn’t require a soft body would need to be made without a skeleton (because you really don’t want to deal with the character/engine stuff and skeletal meshes due to lighting if you can avoid it).
This one case you obviously should use skm and characters.
As such, you need to structure your mesh and bone structure so that it makes sense. Every metal part that would not bend becomes a single armature/skeleton bone.
Because it is a robot and the piece will only ever move with that one bone, you can get by 100% by weightpainting the specific part to the bone with a full weight paint (eliminating a lot of the issues you normally get).
For the stretching part, you shpuld probably avoid them honestly. But when you need them they usually involve painting the weight paint to multiple bones based on taste.
Latest take a classic spring leaf or “bow” exmple.
You have the handle and the tip of the limb.
In the simplest of cases, your handle has a bone which weights the handle area at full weight, while the tip has a bone that moves, which weights the rest of the mesh in a gradient like fashion, where the tip is at full weightpaint and the handle’s end (or riser if you know bows) is at 0. Thus, dragging the tip bone around will cause the bow to “flex”.
Everything else is done similarly, it just becomes much less straightforward and time consuming to apply a good weight paint, which is normally just trial and error on soft bodies.
