GuideWhat Is a Straight Build in Gunpla?
The first time I heard "straight build" tossed around in a Gunpla thread I assumed it meant something technical, like a specific joint assembly or a grade of kit. It is much simpler than that.
A straight build is a kit assembled exactly as the manual shows it, snapped together with no glue, no paint, and no cutting or reshaping of parts. What you get out of the box, in the colors Bandai molded, is what ends up on your shelf.
That sounds basic, but I want to walk through what actually counts, because the line gets blurry once panel liners and top coats enter the picture, and a lot of newer builders worry they are somehow cheating by staying simple.
The core definition
Straight building means following the instruction manual step by step with nothing added and nothing altered. The plastic is pre-colored by Bandai's molding process, so a Gundam's white armor is a white sprue, the red thruster parts are a red sprue, and so on. You clip the pieces off the runners, clean up the attachment points if you want to, and click everything into place using the kit's own snap-fit joints.
No cement, no polycap swaps, no filing down seams, no airbrush. If you stopped at that point and put the kit on a shelf, that is a straight build. It is also, worth saying plainly, the way the vast majority of Gunpla ever built have been finished. Most owners never touch a paintbrush.
Why it is a completely legitimate way to build
There was a stretch of hobby culture online where straight builders got treated like they were doing the lesser version of the hobby, and I think that framing is backwards. Bandai engineers these kits so that color separation happens through the plastic itself, not through paint. A modern Master Grade or Real Grade kit can carry five or six colors molded into individual parts before you have touched a single tool. That is not a shortcut, that is decades of injection molding refinement doing real work.
Straight building also respects what a lot of people actually want from this hobby: an evening or two of focused assembly that ends with a display-ready robot, no drying time, no ventilation setup, no risk of ruining a good kit with an uneven coat. If that is the build you want, you are not missing anything by skipping paint. You are using the kit the way it was designed to be used.
How far you can push a straight build
Here is where the category gets interesting, because "straight build" has some accepted extras that do not count as painting in the traditional sense. Panel lining is the big one. Running a fine liner or panel line pen into the recessed lines molded into the parts adds contrast and shadow depth without changing the base color of anything, and it is done after final assembly rather than during it. Most builders I have seen discuss this treat panel lining as compatible with a straight build, since you are enhancing detail that is already molded in, not adding new color choices.
A top coat is the next step past that, usually a matte or flat spray applied over the finished, panel-lined kit. It knocks down the factory shine and helps the panel lining sit visually. Some purists draw the straight-build line right before top coat, arguing any spray can counts as finishing work outside the strict definition. I do not think that distinction matters much in practice. If you have not repainted a single part and you are still using the kit's own molded colors, calling it a straight build with panel lining and top coat holds up fine.
Where the line actually breaks
The straight build label stops applying once you introduce new pigment to a part's surface, whether that is a full repaint, a wash used to change a color rather than shade it, or paint markers used to add panel lines in a color the kit was not molded in. It also stops applying with any permanent modification, gap filling with putty, sanding away seams, or swapping stickers for waterslide decals with heavy setting solution work. None of those are bad choices, they are just a different category of build, usually called a semi-gloss build or just "detailed build" depending on how far it goes.
Nub marks are their own small debate inside straight building. Clipping parts flush and doing a light sand or scrape to remove the nub stub is still considered straight building by most people, since you are cleaning up a manufacturing artifact rather than reshaping the part. Leaving visible nub marks is also completely fine and extremely common, especially on a first kit.
A straight build is any Gunpla kit assembled from the box in its molded colors with no paint or permanent modification, and panel lining plus a top coat still fits comfortably inside that definition.
Common questions
Does panel lining count as painting?
Not in the way most builders use the term. Panel lining fills recessed lines already molded into the kit rather than adding new color to a flat surface, so it is generally treated as part of a straight build.
Do I need an airbrush to do a straight build well?
No. A straight build by definition uses no paint at all. The only tools most people reach for are a side cutter, a panel line pen or fine liner, and sandpaper or a hobby knife to clean up nub marks.
Is a straight build worse than a painted build?
Worse is the wrong word. It is a different result with different time and skill investment. Bandai molds these kits so a straight build looks accurate to the box art without any paint, which is exactly what a lot of builders want.