How to Model a Robot

Alex Novitskiy did a detailed breakdown of his Terminator-inspired project.

10 min readJun 24, 2018

Introduction

Hi, my name is Alex Novitskiy and I’m a CG Artist from Kiev, Ukraine. In this article, I’m going to tell you how I built a badass rusty robot.

Idea

I’m a big fan of old sci-fi movies and books. I spent a lot of time reading books of Isaak Asimov, Ray Bradbury, Robert Sheckley, Kurt Vonnegut, Strugatsky Brothers and watching movies like Terminator, Blade Runner, etc. I looked for a good idea to practice hard surface modeling combined with advanced texturing techniques. I thought It would be great to make old-fashioned sci-fi robot.

Style

I decided to develop my own concept for this idea, which I based on an old-school heavy design from VHS movies from 80’s and 90’s like Terminator and Judge Dredd. I mixed it with a chopped polygonal style I love very much in franchises like Deus Ex and Dishonored.

As any old-fashioned mechanism, this robot should look like a mess of raw metal parts, cylinders, hoses, and wires, covered in rust, of course. It’s a brutal way I like.

This iron bastard represents war, he is a bad guy. So, let me ask you: what do you know about war? Which associations you have? Feelings? Death? Fear? What else?

In our imagination war is always associated with death. Skull is a symbol of death in most cultures in the world. That is why classic sci-fi movies use the skull to emphasize feel of danger and fear as the main and the most recognizable element of almost any human-like killing machines, cyborgs.

Idea was to create an awakened mechanism, so I found many references with the same idea: old and rusty ABC from Dredd, self-repairing M.A.R.K. 13 from Hardware, T-600 from the first Terminator, a raw welded mask of Corvo Attano from Dishonored. All of them uses the skull as a core element of the character as a symbol of death.

First, I created many similar face models using different approaches which are based on different styles based on characters from games and movies I like. I took best elements from many concepts I made and combined it into one.

Model

This old junk is not a simple rusty tank. It’s an old, human-like perfect killing machine. He can run, catch you, kill you, but he is not too fast. For the maximum variety of movement, his body was made close to a human anatomy. On the other hand, he is a heavy guy, his armor designed to catch bullets and handle small explosions.

I used human skeleton and muscles as a reference in my work. I researched T-600 and T-800 as well as many other robots from old sci-fi movies for an understanding of how they were built. It helped me to combine flexible human shapes with heavy solid pieces.

Tip: All humanoid robot designs are based on human anatomy, so understanding of it is a clue to a believable model.

Head

Let’s talk about construction first.

The skull is the core element of character representation. So I tried to combine both design and functionality. I think the skull (not a concept, but the final model) and chest were the hardest parts.

Head has many holes and sockets, you can see what does each hole and socket mean on the images below.

Skull is a cast metal piece, so there should be a hatch for repair and easy way to access inside. For extra cases and quick access, I added a small hatch too. Also, I added sockets for charging some elements without opening head on the top of the hatch.

The bottom of the head not just looks complicated, it really is. All the spine and chew hydraulics start here.

Head is the main object, it’s a container of the positronic brain! So it should be solid and looks well protected.

To make my character more live, I decided to make a movable chew, so I designed a hydraulics for it.

Tip: Elements like movable chew can make your character more interesting. It can’t be used on the battlefield, but it’s a good idea to make the robot more human-like.

Body

This part gathers head, arms, and pelvis into one structure. It’s a heavy, massive and brutal piece of cast metal. The chest has three main tasks: protection, movement, and design. I tried to achieve brutality in design, and save all necessary functionality robot should have.

To achieve a believable look, it’s necessary to understand the meaning of each detail, even if it’s only a design element. For example: if you creating a hatch, you should understand what this hatch should hide from our eye. If you want to add some detail and you do not know what it means, you’re adding it only because “it looks fine”, you should not add it.

Shoulders have all necessary degree of freedoms to move hands in any direction.

Tip: Before creating part like this, think how it will move. Create a simple blockout first, then try to animate it.

Pelvis

This is third important part of the iron bad guy. You can see below how leg connects to a pelvis with ball hinges.

At the back, I made some hatches for quick service and for easy access inside pelvis cast piece.

I tried to support main shapes of the head and body with raw, brutal lines in design. This thing is less massive and acuter then chest.

Tip: To make details more interesting, you can think about different types of similar joints. As an example, my robot has silent blocks in some places and different types of joints.

Arms

Hands without armor look like skeleton hands as you can see below. Armor makes it feel more solid and heavy.

Tip: Armor should not look like design element only. It should save hand from the damage in the battle.

Legs

Design of the legs is close to other parts of the body. It’s raw, acute and looks dangerous. Hydraulics here I made very similar to a T-600 from the first Terminator.

Tip: If you model foot, think how the robot will step on it. Add amortization on the heel and think how it will handle the weight of the robot.

Materials

Materials here represent the history of the machine, how it was used and where. I like when textures can speak for itself. It’s a story of the object.

My robot is an old mechanism created for death and destruction. Now he was awakened by a new host to kill for them.

I worked in PBR pipeline (Spec\Gloss) on BRDF shader in Mari. I created mask stacks and shared it with all channels for each material to make workflow flexible and comfortable.

I used gradients to highlight the main parts. It was a black falloff from legs-to-head and orange gradients with color spots in the top of edges on each part. This is the way Blizzard uses to create textures for their characters. My robot is less cartoonish so I made these gradients less visible.

There are total six materials on the model:

1.Metal

It’s just a steel. Old, scratched steel.

2. Coating

The coating layer is very simple in my case. With little turbulence in albedo.

3. Paint

It’s the most complicated material here. I used turbulence node for the base color, 3 types of gradients (dark, bright and color spots) for uneven color effect and grunge maps (albedo and gloss).

4. Rust

Rust was made with 2 grunge maps and curvature map. I made little paint effect all over the model to make it more live. The same scheme as in the paint: grunge maps in albedo and gloss.

5. Dirt

Dirt is just grunge map based on the cavity.

6. Oil

I have totally 2 oil colors: green and black. Black is an old, dry. Green is fresh.

For scratches, I used next principle: smooth scratches all along borders with sharp blotches. Smooth scratches helped me to achieve style effect I wanted. If you will use only smooth scratches, it will make your texture seems very low res, so there should be some small blotches with sharp scratches as you can see on the image.

All scratches should vary. The robot is a complicated mechanism, so different parts of him have different wear. Some places can be more scratched, some — less. The type of scratches can vary too. Everything depends on the part. You should understand how it was used, when and where robot got all this wear.

To demonstrate that this robot is old, I erased all factory signs a little. After that, I added new signs of use — a sign of peace on his back made by a human. So now you know that someone scratched it for some reason. This is a part of a story you can read from materials.

Tip: Try to make your Albedo as deep as possible. In flat color, it shouldn’t look as solid color. Add some spots here and there, vary color with turbulence or noise, feel free to add gradients, etc. Paint it a little, at the end. It will make your material more live.

Some words about mesh and UV

An accurate mesh is highly desirable for a cool final result. I like precise topology and clean meshes. It will be much easier to work with UV if your model is accurate. Do not forget to make the same texel for all the UV’s and pack it well!

Tip: To work with the whole model in Mari you should previously save your model as obj or fbx, not as a single mesh. It should be one file with selection groups. To make this, select object(s) in Maya, then choose to Create — Set — Quick Select Set…, then create one per object(s). After you import it into Mari, you will find your model with saved structure. So now you can turn off any part and work with a desirable element.

Renders

The light here is a clue to a character representation. I chose a scheme with a Spot above (main light), two Directional sources at the back and one Omni at the front for ambient. I moved lights for each render individually.

Tip: do not make all lights with the same color and temperature. Vary it a little. It will make the final result more live. Use warm colors at the front and cold in the back.