Extensions¶
A building doesn't have to consist of a single body. On the free floor plan you add up to ten extensions next to the main building — each with its own height and its own upper end. You create them in the Floor plan step; you set their top end in the Roof step.
What an extension is¶
An extension is a self-contained secondary body next to the main building — not a projection of the main building, but a body of its own with walls of its own.
- An extension always has just one floor. Only the main building gets the floors from the Floors step.
- Every extension has its own eaves height. It doesn't depend on the ceiling heights of the main building.
- Main building and extensions share one base plate. Wall heights and roofs are created independently of it.
- Extensions exist only with the floor-plan shape Free — not with rectangle, L, T and U.
- More than 10 extensions per floor plan are not possible. If you want another one after that, remove an existing one first.
Creating extensions¶
Extensions are created in the Floor plan step, when you apply your drawing:
- Draw all outlines in the drawing editor — main building and extensions together.
- Click "Apply floor plan".
- Click the main area first, then the extension areas one after another.
- "Done" completes the assignment.
An extension has to adjoin the main building — or an extension you have already assigned before. An area that doesn't connect anywhere can't be applied as an extension.
Every extension gets a fixed color of its own — with ten extensions ten different ones, none repeats. The color is the same in the drawing area, in the "Extensions" panel and in the 3D preview, so it's always clear which body is meant.
Changing an existing floor plan¶
If you click "Edit" on a saved floor plan, the main building and the extensions come back as a drawing — each extension as its own area.
- Change the outlines as you did the first time.
- Click "Apply floor plan".
- Assign again: the main area first, then the extension areas, then "Done".
Guide lines do not come back
What is restored are the outlines, not the drawing you built them with. Guide lines and the undo history start empty.
Height, Active and Passage¶
The assigned extensions are listed on the right in the collapsible "Extensions" block — one row per extension with a colored dot, name and a number tile — the same one as for the floor-to-floor heights above, with which it is also flush.
Minimum distance to the main building's eaves
If an extension touches the main building, its eaves must stay at least 0.50 m away from the eaves of the main building. The values in between therefore never appear in the tile at all: if the main building is at 3.20 m, the button jumps from 2.70 m straight to 3.70 m.
If the extension only hangs off another extension and touches the main building nowhere, the distance does not apply. Its eaves may then sit at exactly the same height as the eaves of the main building.
| Setting | Range |
|---|---|
| Height (eaves height above the base plate) | 0.30 m to 20.00 m |
| Step size | 0.10 m |
| Starting value of a new extension | 2.00 m |
In addition there are two switches per extension:
- Active — off: the extension is not built. All its settings are kept, and you can switch it back on at any time.
- Passage — opens the dividing wall over the clear inside width of the extension, so that the two rooms flow into each other. For room colors and floor textures, main building and extension then count as one single room; without a passage they stay two.
Passage: to the main building first¶
The passage always goes to the main building first: if the extension touches it, it is exactly that dividing wall that opens — even when the extension also adjoins further extensions alongside. Only if it doesn't touch the main building at all does the passage go to the neighboring extension. So if extension 2 hangs on extension 1 and not on the main building, its passage opens the wall between the two extensions.
Who owns the dividing wall makes no difference here — the passage opens it either way.
At the top the passage always ends where the roof begins at that spot — and it does so on both sides of the wall:
| What lies above the passage | Where it ends |
|---|---|
| Sloped roof (its own extension roof, the main roof or the roof of the neighboring extension) | at the underside of the roof face — the cutout follows the pitch |
| Flat roof, roof terrace or "No roof" | at the eaves height of the body concerned |
| Floor slab of the main building (multi-storey main building) | at the underside of the slab |
Of two limits the lower one always applies: the passage never stands above a roof out in the open.
Who owns the dividing wall?¶
Two adjoining bodies share one exterior wall as the dividing wall — between the two interiors there is therefore one wall of 0.40 m and not twice 0.40 m. It is built only once, and by exactly one of the two bodies.
Who owns it is decided by whose wall runs through at that spot:
- If the wall of one body runs on past the shared stretch and the other's doesn't, the wall belongs to the body that runs through. That can be the extension too — the main building then builds no wall of its own there.
-
If both run through or neither does, the old ranking applies, in this order:
- The main building always wins.
- If an extension hangs on another extension, the one it hangs on wins.
- Among the remaining neighbors — above all two extensions on the same body — the taller one wins.
That keeps the wall line continuous: it doesn't step by one wall thickness just because the owner changes along a run of wall.
The roof outline moves along
If the wall that runs through belongs to the extension, it sits one wall thickness outside the outline of the main building. The roof of the main building moves outwards with it at that spot — otherwise the wall above the extension roof would stand next to the roof out in the open.
If the extension is taller than its neighbor, it sits on the same wall flush at the top.
Extensions and upper floors¶
If you draw an upper floor, those areas of the extensions that reach past the underside of that floor are locked. They lie hatched in the plan and can't be applied as an area there.
What is locked is the applying, not the drawing
Over a locked zone you may keep drawing — guide lines stay allowed. Only the area itself can't be applied there.
The upper end¶
You set what happens on top of an extension in the Roof step. There you first pick the body — Main building, Extension 1, Extension 2 … — and then one of three options:
| Choice | What the extension gets |
|---|---|
| Roof of its own | A roof just for this extension. You then pick the roof shape; that includes "No roof" — the extension then ends flat at eaves height and stays open at the top. With a gable or shed roof you click the ridge reference edges on the outline of the extension. |
| Roof terrace | A flat roof with a railing on the exposed edges. Edges against a taller wall don't get one. |
| Extend the roof of the main building | No roof of its own: the main roof is built over the main building and the extension, and the walls of the extension run up to underneath it. |
Choose the ridge reference edges again after extending
With "Extend the roof of the main building" the outline of the main roof changes. You have to choose the ridge reference edges of the main roof again afterwards — see Roof.
Minimum distance between the roofs¶
The roof surfaces of extension and main building must not touch: at the narrowest point 5 cm of distance must remain, roof overhang included. If the distance falls below that, the app reports it and doesn't build.
Whether the distance suffices depends on the heights: the extension roof rises from its eaves height, and once its ridge reaches the main building's roof slab, no distance is left. The app then names both ways out — make the main building taller or the extension lower.
A measured example: main building 12 × 9 m with a flat roof, extension 4 × 4 m with a 30° gable roof and an eaves height of 2.60 m. At 3.80 m main building height the app refuses; at 4.00 m it builds. Lower the extension's eaves height to 1.50 m instead and it builds as well. So a main building with a flat roof does carry an extension with a roof of its own — it just has to be tall enough.
What else an extension has of its own¶
An extension is a body of its own in the following steps as well:
| Area | What the extension has of its own |
|---|---|
| Openings | Its own windows, doors and cutouts in its walls — including several windows spread evenly across an extension façade. See Openings. |
| Interior walls | Interior walls of its own inside the extension. They snap to its inner edges just as in the main building and divide the rooms there in the same way. See Fit-out & Add-ons. |
| Textures | A façade texture and a roof texture of its own, independent of the main building. See Textures. |
| Visibility | A switch of its own in the "Visibility" panel. See Tools. |
| Printed parts | In individual-part mode, extension walls are separated using the same corner profiles as the main building walls and oriented for printing. Its roof is a printed part of its own — in the monolith model from 1:100 as well. See Connectors & splitting. |
| Connectors | At the dividing wall the extension plugs into its neighbor with a dovetail joint — up to 1:99. See Connectors & splitting. |