Building a Martian Gunpla Diorama Base: Barbatos vs Hashmal Part 3
TL;DR: In Part 3 of this Gunpla diorama build, the raw foam and textured terrain finally becomes a Martian battlefield. Using dark base colours, washes, dry brushing, earthy reds, dusty browns, and weathered highlights, the base starts to feel dry, hostile, and battle-worn. The result is the perfect stage for Gundam Barbatos and Hashmal.
After all the cutting, carving, layering, and texture work from Part 2, the diorama had finally reached the stage where everything starts to come together.
Paint.
Up until this point, the base was still obviously foam, paste, sand, gravel, and rough construction. The shape was there, the story was there, and the composition was working, but it still needed life.
Painting is what transforms terrain into a believable environment. It is where the battlefield stops looking like a project and starts becoming a world.
For this build, that world was Mars.
More specifically, it was the harsh, dust-covered battlefield from Mobile Suit Gundam: Iron-Blooded Orphans, where Gundam Barbatos faces the relentless Hashmal.
The colours needed to feel dry, hostile, and heavy. Not bright red like a clean sci-fi postcard version of Mars, but something darker and more grounded. Dusty earth tones, weathered rock, deep shadows, scorched ground, and the kind of surface that looks like it has been scarred by centuries of conflict.
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Starting With the Dark Base Colours
For the base colour, I started with dark.
That is one of the biggest lessons I have learned with terrain painting: always begin darker than you think you need.
It is much easier to build highlights upward than it is to recover depth after starting too bright. If the first layer is already too light, the terrain can quickly look flat, dusty in the wrong way, or too clean.
This battlefield needed weight.
The first layers were deep browns, muted reds, and dark, earthy tones across the cliffs and ground. These colours became the foundation of the Martian surface.
Rather than trying to create every colour variation immediately, I focused on building the shadow first. The cracks, cliff bases, low points, and broken ground all needed that darker foundation before any dust or highlights could work properly.
Depth matters more than colour.
Why the Martian Colour Palette Matters
Mars is usually associated with red, but for a diorama, using one flat red would have made the base look unrealistic.
Real terrain needs variation. Even a red planet needs browns, greys, ochres, dark shadows, pale dusty highlights, and worn edges. The goal was not to paint the base “red.” The goal was to make it feel like dry, damaged, Martian ground.
For this build, I wanted the colours to suggest heat, dust, erosion, and old violence.
The terrain had to support the story of Barbatos and Hashmal. It could not feel like a clean display stand. It had to feel like a place where something brutal had already happened, and something worse was about to happen.
That was the mood I kept coming back to while painting.
Not clean.
Not bright.
Not pretty.
A battlefield.
Adding Washes for Shadow and Age
Once the darker base tones were established, I moved into washes.
Washes are where the atmosphere starts to happen.
Thin dark washes were worked into the cracks, around the cliff bases, between rock layers, and into the deeper ground details. This helped create shadow, age, and a stronger sense of scale.
The texture work from Part 2 really started paying off here. Every carved crack and rough surface gave the wash somewhere to settle. That is why texture is so important before painting. Washes need detail to grab onto. Without that surface variation, they do not have as much impact.
The washes also helped break up the cleaner base layers. They made the ground look older, dirtier, and more lived-in.
Battlefields should not look fresh.
I wanted the terrain to feel like it had existed long before Barbatos arrived, like Hashmal had already torn through this place before the final confrontation even began. That history matters.
Dry Brushing the Rocks and Broken Ground
After the washes had settled, I began layering lighter shades over the raised surfaces.
Dry brushing is one of the most effective techniques in diorama painting, especially for rock work. It catches texture naturally and instantly gives the surface more dimension.
Lighter dusty browns, soft stone greys, faded reds, and pale earth highlights were gradually brushed across the raised areas. I focused on the cliff edges, broken ground, rubble, and any section where the texture needed to stand out.
This is where the cliffs really came alive.
All the cutting, carving, and rough texture work suddenly became visible. The cracks looked deeper. The layers of erosion stood out. The ground started to feel old and worn instead of freshly built.
That is the magic of dry brushing: it rewards good texture.
Building Up Dust Without Losing Detail
With a Martian base, dust is everything, but too much dust can flatten the whole scene.
I wanted the terrain to look dry and powdery without covering all the work underneath. The trick was to build it slowly, especially across the open ground and rubble.
The dusty highlights helped connect the different areas of the base together. The cliffs, broken surface, and lower battlefield all needed to feel like they belonged in the same environment.
I also kept the dust tones slightly uneven. Some areas were warmer and redder. Others were more faded and grey. This helped stop the base from looking like one solid colour.
A battlefield should feel irregular. Dust gathers differently around rocks, cracks, slopes, and impact zones. Adding that subtle variation made the surface feel more natural.
Making the Terrain Feel Battle-Worn
At this stage, the base was no longer just Martian terrain. It needed to feel like a battlefield.
That meant thinking about where the action would happen. The central area needed to feel disturbed. The rear cliffs needed to frame the confrontation. The front still needed to stay open enough for the viewer to see the full scene once Barbatos and Hashmal were added.
The painting had to guide the eye.
Darker tones helped create weight in the deeper cracks and around the base of the cliffs. Lighter dry brushing helped pull the raised edges forward. Dusty red tones tied the whole surface together.
I wanted the viewer to feel the harshness of the environment before the mobile suits were even placed on it. That is the power of a good diorama base. It does not just hold the model, it sets the scene.
Knowing When to Stop
Knowing when to stop is part of the skill.
It is very easy to keep adding more paint, more dust, more shadows, more highlights, and more weathering. But eventually, the battlefield was done.
The cliffs framed the rear of the base exactly how I had imagined. The broken ground carried the weight of the confrontation. The dusty red tones gave the entire scene that unmistakable Martian atmosphere.
Most importantly, it felt like a story.
That is what I wanted from the beginning. It was not just a display stand or a background. It was a moment.
A battlefield where Barbatos could stand against Hashmal, and the environment itself would support that tension.
Why Painting Changes Everything in a Gunpla Diorama
Looking at the finished piece reminded me of why I love building dioramas so much.
A great Gunpla build is satisfying on its own, but a custom base changes everything. It gives the model context. It gives it emotion. It turns a finished kit into a scene worth stopping for.
Part 1 gave this build its story and layout.
Part 2 gave the battlefield its shape and texture.
Part 3 gave it atmosphere.
That is the difference paint makes. It connects all the earlier decisions and makes the whole scene feel intentional.
The foam disappears.
The texture becomes rock.
The sand becomes dust.
The base becomes Mars.
Key Takeaways
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Start darker than you think when painting terrain.
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Use muted reds, browns, greys, and ochres instead of one flat Mars red.
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Washes help add depth, age, and shadow to cracks and rough texture.
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Dry brushing brings out carved rock, rubble, and raised surface detail.
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Dust effects should be built slowly so they do not cover the texture underneath.
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A good diorama base should support the story, not distract from the model.
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Painting is what turns raw materials into a believable environment.
Frequently Asked Questions
What colours should I use for a Martian diorama base?
For a Martian diorama base, use a mix of dark browns, muted reds, rusty oranges, ochres, greys, and dusty highlights. Avoid using one bright red across the whole base, as this can make the terrain look flat and unrealistic.
Should I paint terrain dark or light first?
It is usually best to start dark when painting terrain. Dark base colours create depth and shadow, while lighter tones can be built up gradually with dry brushing and highlights.
Why are washes useful for dioramas?
Washes settle into cracks, gaps, and textured areas, helping create shadow and depth. They are especially useful for rock faces, rubble, damaged ground, and weathered terrain.
What does dry brushing do on a diorama base?
Dry brushing catches the raised texture on rocks, rubble, and ground surfaces. It helps bring out detail, makes edges stand out, and gives the terrain a more realistic, weathered look.
Can I use these techniques for other model bases?
Yes. The same techniques can be used for Gunpla bases, model railway terrain, military dioramas, fantasy miniatures, sci-fi displays, and other scale model scenes. The colours may change, but the process of dark base colours, washes, dry brushing, and weathering is very versatile.
Final Thoughts
For now, this battlefield feels complete.
Barbatos has its ground. Hashmal has its stage.
And what started as a few pieces of foam has become one of my favourite display projects I have built so far.
Sometimes the best part of Gunpla is not the kit itself. Sometimes, it is the world you build around it.
Missed the earlier parts of the build?
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In Part 1, I planned the overall concept, layout, and Martian battlefield composition for the Barbatos vs Hashmal display. Building a Martian Gunpla Diorama Base: Barbatos vs Hashmal Part 1
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In Part 2, I built up the cliffs, carved the terrain, added texture paste, and used sand, gravel, and rubble to create the broken battlefield surface. Building a Martian Gunpla Diorama Base: Barbatos vs Hashmal Part 2
Catch up on Parts 1 and 2 before starting Part 3, then follow along as the full diorama comes together.
For more tips and tricks, follow me on socials @rosie_custom_gunpla
