Exploded Axonometric
Axonometric drawings that separate and display building components to reveal spatial relationships and construction logic.
An exploded axonometric is a measured three-dimensional drawing in which a building or object is pulled apart along one or more axes, so that each layer, component or floor can be seen on its own while still lining up with the parts around it. It combines the scale accuracy of an axonometric projection with the clarity of an assembly diagram, which is why architects use it to explain structure, construction sequence and programme in a single image.
What is an exploded axonometric?
An axonometric is a parallel projection: lines that are parallel in the building stay parallel on paper, and nothing shrinks with distance. The Wikipedia article on axonometric projection explains that the word means "to measure along the axes", and that because scale does not depend on position, the drawing can relay precise measurements in a way perspective cannot. Architects use four main families:
- Isometric: the three axes are equally foreshortened and sit 120 degrees apart, so one scale works in every direction.
- Dimetric: two axes share a scale and the third is drawn at a different one, set by the viewing angle. Trimetric drawings, with three separate scales, are rarely used in practice.
- Oblique: one face is drawn in true shape and the depth recedes at an angle. In cabinet projection the receding axis is drawn at half size, a convention popular in furniture illustration.
- Plan oblique: the true plan is rotated, usually by 45 degrees, and the heights are projected straight up. Wikipedia describes this as military projection, in which the plan is rotated but not skewed. It is the quickest axonometric to build from an existing plan.
English usage is not fully consistent. In German literature "axonometry" covers every parallel projection, oblique included, while English texts sometimes reserve the word for views that rotate the object rather than skew it. On an architecture board the word usually means any of the four.
"Exploded" adds movement. An exploded-view drawing shows the components of an object slightly separated, as if a small controlled explosion had pushed every part an equal distance from its original position. In architecture the parts are usually floors, roofs, structural frames, envelopes and furniture layers, separated vertically so that each one can be read in plan and in relation to the rest.
"Three-dimensional (isometric) illustration that shows the mating relationships of parts, subassemblies, and higher assemblies. May also show the sequence of assembling or disassembling the detail parts."
The exploded axonometric is one member of a wider family of 3D diagrams, and it overlaps with the axonometric diagram, which keeps the building together but strips it down to one idea.
A short history of the exploded axonometric
The exploded view itself is a Renaissance invention. Wikipedia traces it to the early fifteenth century notebooks of Marino Taccola, refined by Francesco di Giorgio and Leonardo da Vinci, whose design for a reciprocating motion machine is one of the first clear examples. The measured axonometric came later. William Farish of Cambridge published detailed rules for isometric drawing in 1822, and from the middle of the nineteenth century isometry spread from engineering into architectural training.
Architecture's own tradition begins with Auguste Choisy. In his Histoire de l'architecture of 1899, as the Dictionary of Art Historians records, he developed single drawings that combined plan, elevation, section and perspective. Many are seen from below, so that the plan sits at the bottom of the page and the vaults rise out of it.
The historian David Watkin, quoted in the same dictionary entry, wrote that Choisy
"interpreted architecture exclusively in terms of the history of construction, demonstrating what he believed to be its essence in a series of grimly clever diagrams."
David Watkin, The Rise of Architectural History (1980), quoted in the Dictionary of Art Historians
The axonometric became a modern design tool in the 1920s. According to Jan Krikke, cited on Wikipedia, its popular acceptance came when architects from the Bauhaus and De Stijl embraced it, and Theo van Doesburg's axonometric designs caused a sensation when exhibited in Paris in 1923. His counter-constructions go further than a building view: planes of colour float apart from each other, already halfway to an exploded drawing.
Later in the century, the Wikipedia article on architectural drawing notes, axonometrics featured prominently in influential 1970s drawings by Michael Graves and James Stirling, including worm's-eye views, exaggerated rotations of the plan and exploded elements. Today the projection is a standard feature of CAD systems, so a model can be exploded in minutes rather than redrawn by hand.
Key principles of the exploded axonometric
Choose the projection for the building
Plan oblique suits buildings whose plan is the main story, because the plan stays true and can be traced from the drawing set. Isometric suits objects that need to be read equally from every side, such as a structural node or a pavilion. William Farish's 1822 drawing of an optical-grinding engine, below, shows why isometric suits machines and nodes: every bar and wheel is drawn at one scale, so the parts can be measured straight off the page.
Explode along one axis, in the order of assembly
Most architectural explosions are vertical: foundations at the bottom, roof at the top, each layer lifted by the same distance. Wikipedia notes that in mechanical drawings the part closest to the centre is usually assembled first, while outer parts come off first. The same logic works for buildings. Keep the separation equal and use thin dashed lines to show where each layer returns to.
Keep the assembled view close by
The United States Patent and Trademark Office rule for design drawings is a good habit for architects too: an exploded view is only supplementary to a fully assembled view, and a bracket shows which elements belong together. A small assembled axonometric in a corner of the sheet lets the reader check that the parts add up to the building.
Cut away or explode
Not every interior needs an explosion. A cutaway removes the roof or one wall and keeps everything else in place, which suits a continuous sequence of courtyards or galleries. urban:PROCESSOR by Milica Jovičić, which treats a membrane as an "urban dam" between heavy traffic and a green oasis of cultural and recreational spaces, is drawn this way.
Annotate the layers
Labels turn a pretty drawing into an explanation. In Visualization' 20 - The Hollow Project by irem metin, a co-housing project near the historical wall in Istanbul, entered in the Visualization '20 competition, a section perspective names the steel load-bearing system, the reinforced concrete and the raft foundation, with floor levels listed beside the cut.
How to draw an exploded axonometric
By hand, the traditional tools are a parallel rule and set squares. The architectural drawing article notes that drafting with 30/60 and 45 degree set squares fixed the angles used in these views. A practical sequence:
- Decide what the drawing must explain and list the layers in order of assembly.
- Trace each floor plan and roof plan, rotate them to the same angle (45 degrees for plan oblique, 30 degrees for isometric) and stack them on one vertical axis with equal gaps.
- Project walls and columns upward from each plan to their true heights, using the same scale throughout.
- Draw thin dashed guide lines between the layers at a few corners so the eye can reassemble them.
- Use line weight to separate cut edges, outlines and background, and add tone or one accent colour only where it carries meaning.
Digitally, the process is the same but faster. Set the modelling software to a parallel (not perspective) view, place each layer on its own group or layer, duplicate the model, and move each group along the vertical axis by a fixed distance. Export the linework as vectors and finish line weights and labels in a drawing or layout program, where it is easier to control than in the model.
Exploded axonometrics on uni.xyz
uni.xyz members use the technique for everything from a single house to a space colony, often as the drawing that holds a competition board together.
Fast forward to the FUTURE by Hamed Behkam and Hila Khatat is the most liked project in this topic and a winning entry in the Memory competition. The team writes that architecture is for the future rather than the past, and frames a Grand Arc of Aleppo that refers to the past while serving what comes next, with participation spaces that draw on the existing layers of the site.
The series "a home exploded" takes the technique literally. Two volumes appear as projects: a home exploded, vol. 4 by Joyce HuangOoi, Tomy Stankiewicz, Ryan Lew and Marco Luna, and a home exploded, vol. 2 by Michael L., Raina Lee, Gabriela Guevara and Darlene Ifeorah. Michael L. has also published the series as four journals, from volume 1 to volume 4. The project statement argues that a home takes its identity from what its inhabitants fill it with: memories, traumas, possessions and people. Pulling a house apart becomes a way of showing those contents.
"A house cannot be a home without its host."
Project statement for a home exploded, vol. 4 and vol. 2 on uni.xyz
Affordable Housing For the Bede Community by FATEMA-TUZ ZOHORA, entered in UnIATA '24, proposes adaptive heritage dwellings and peels one apart layer by layer with its materials keyed beside it, while Proximity Land by Amreen Imran repurposes an old oil rig and separates its decks and frames on a dark ground. Other members push the technique into new building types. Glashaus by Tim Hardeman and Diana Kuzina, entered in the Bauhaus Neue competition, houses 24 foreign students for two months at the Bauhaus and groups them by floor regardless of ethnicity, a plan idea that an exploded stack of floors explains directly. OR1GYN: space habitat by Isabela Nakamura and Luís Pereira takes its form from the sunflower, with connected petals of 1,000 people each holding its own biome as the colony grows from 2,000 to 10,000 inhabitants. Tectonic Variation by Sara AlJaljuli and Habiba Mohamed, which received an Institutional Excellence Award in the Cultural Conserve competition, displays the traditions of Shirakawa-go on a wooden tectonic facade, the kind of assembly that exploded drawings were made for.
Challenges and future directions
The exploded axonometric is easy to overdo. When every wall, beam and chair floats free, the drawing becomes a cloud of parts that no one can reassemble. The fix is restraint: fewer, larger layers, consistent gaps and one clear sequence. A second risk is that the drawing explains the construction while hiding the experience of the space, so it works best beside a section or a perspective rather than instead of them.
Digital tools have changed the economics. An explosion that once took days of hand projection can now be generated from a building information model, and animated so that the building assembles itself on screen. That makes it tempting to explode everything by default. The drawings that still stand out are the ones where the separation reveals something, such as a hidden structural move, an unusual stacking of programme or a construction sequence that matters to the design.
Exploded axonometrics for students and designers
For a thesis, the exploded axonometric is a natural spine: one drawing that shows structure, envelope, programme and circulation as stacked layers, supported by plans and sections. Good research angles include comparing Choisy's up-views with contemporary BIM explosions, testing how far one exploded drawing can replace a set of plans, or documenting a local construction system layer by layer.
ANGANWADI by satish kumar, entered in the Grassroots competition, aims to give street children a place to learn away from the drudgery of city roads. Its board already stacks plans from ground to roof, and turning that sequence into a single exploded axonometric is a good exercise for any student. Related reading on uni.xyz includes technical drawings and architectural assemblage, and the uni.xyz competitions page lists open briefs where a strong exploded drawing can carry a board.
Frequently asked questions
What is the difference between an axonometric and an isometric drawing?
Isometric is one type of axonometric. In an isometric the three axes are equally foreshortened and sit 120 degrees apart; other axonometrics, such as dimetric, trimetric or plan oblique, use different angles and scales.
What is a plan oblique drawing?
A plan oblique keeps the floor plan in its true shape, rotated on the page, and projects heights vertically from it. It is quick to construct from existing plans and is widely used for architectural exploded views.
Why do architects use exploded axonometrics?
They show how a building is assembled: which layers sit on which, how structure relates to enclosure, and how programme stacks from floor to floor. Because the drawing is measured, it can explain construction as well as concept.
How far apart should the layers be in an exploded axonometric?
Far enough that every layer reads clearly, usually about one floor height or slightly more, and always the same distance between layers. Dashed alignment lines help the reader put the building back together.
References and further reading
- Axonometric projection, Wikipedia
- Oblique projection, Wikipedia
- Exploded-view drawing, Wikipedia
- Architectural drawing, Wikipedia
- Choisy, Auguste, Dictionary of Art Historians
- Design Patent Application Guide, United States Patent and Trademark Office
