Lots

What a lot is

A lot is a parcel inside a region, and it carries one building. When a region is set to a built land use — Residential or Commercial — the engine subdivides it into lots and runs a building on each of them. Regions come first: the editor's own empty state in this mode reads “No lots yet — Lots are parcels inside blocks — create a block and it splits into lots, or draw a lot directly.” See regions for how a parcel gets typed in the first place.

Reach the mode with Alt+4 or the Lots tab on the left rail of the iCity Editor. The status bar names it back to you as Lots (Alt 4) and lists the mode's vocabulary: D Draw Lot, click to Select, Shift+click to Extend, drag to Box Select, A Select All.

Everything on this page needs the engine running. Your city lives in that separate process, not in your .blend — see how iCity fits into Blender. With the engine stopped the rail is not built and no lot is pickable (the engine).

Selecting a lot and reshaping it

Lots are picked through the addon's gizmos, not Blender's click — keep Blender's own Select tool active in its toolbar or the handles hide (selecting and editing). Click a lot outline to select it, Shift+click to add more, A for all, Ctrl+I to invert.

A selected lot grows a flat square on every corner and a slim bar at the midpoint of every edge. Hold-drag a corner square to move that corner, or an edge bar to move both of its corners together; the reshape is committed when you release. The status bar's drag hint on a selected lot reads Reshape, not Move.

Del on a selected lot runs Delete Lot. That deletes the building sitting on the lot and leaves the lot itself in place, vacant. The confirm says what it means: “This is a persistent edit — a regenerate will not bring it back.” Ctrl+Z is the way back, and only while the last thing you did was an iCity edit.

D arms Draw Lot: click corners, Enter to confirm, Esc or D to exit. Fewer than three points is dropped. The engine registers the polygon on the region containing it — or as a free floating parcel of its own if it sits outside every region — and generates the building for just that lot.

Building or Green

Every lot has one of two content types. Building is the default: the lot carries a building. Green makes it a green surface with no building — switching a building lot to Green deletes the building that was on it. The two buttons sit directly under the selection header in the parameters column of the iCity Editor, and they act on every lot in the selection at once.

Each click rebuilds the lot objects, so the outline you clicked is deleted and replaced by a fresh one behind the scenes. That churn is why the right-click element popup exists as well: it holds on to the anchors of the lot it bound to instead of re-reading the live selection, which is what lets you press Green and Building back to back there without the next press landing on a different lot. The buttons in the parameters column read the selection at the moment you click them.

The type survives into dressing. In Design, Lots mode offers the material categories Soil, Sand & Gravel and Grass — the ground the lot shows where no building covers it. See materials.

Loop cutting a lot

Loop Cut Lot is the first of the mode's own tools on the Lots rail, under the Select tool that leads every mode, and it works like Blender's own loop cut: hover, wheel, click. Its rail tooltip is the whole instruction — “Hover a 4-sided lot: wheel = cuts, click = apply”.

1. Arm Loop Cut Lot from the rail. The status bar switches to Hover Lot · Cuts · Apply · Exit Tool.
2. Hover a four-sided lot. Orange lines preview where the cuts will fall, and the edge they are measured along is highlighted white. The caption reads Loop Cut: 1 Cut.
3. Scroll the wheel to change the count, between 1 and 10. Off a lot, the wheel zooms the viewport as usual.
4. Click to apply. The lot is replaced by evenly spaced strips, each its own lot.

A lot that is not four-sided cannot be loop cut. Hovering one draws no preview and the caption reads Loop Cut: Not 4-Sided; clicking it reports “this lot is not 4-sided — loop cut needs a quad lot”. Corners are counted by turn angle, so a gently curved side still reads as one side.

Cutting a Green lot gives you Green strips. The whole cut is one undo step: a single Ctrl+Z restores the source lot and its building and removes every strip, rather than leaving you on a half-finished intermediate.

Merging lots

Merge is not a rail tool. Select two or more lots, then press Merge Lots, which sits at the foot of the parameters column, below the values that describe what it will act on. In the viewport the same verb is on the right-click element popup for a multi-lot selection.

1. In Lots mode, click one lot, then Shift+click the ones next to it.
2. Press Merge Lots at the bottom of the parameters column. The lots become one lot carrying one building.

Two refusals are worth knowing before you click. With fewer than two lots selected the warning reads “shift-click 2+ adjacent lots (in Lots mode), then click to merge them”. If the lots do not all touch along an edge, the warning is “the selected lots are not all edge-adjacent (their union is not a single face)”. Warnings from these buttons land in Blender's Info editor and the status bar, not in a toast.

A merge is permanent user intent, so the engine keeps it across re-splits. The merged lot stays Green only when every source lot was Green; a merge that swallows one buildable lot produces a buildable lot.

What changes when you split a lot

Splitting or merging is never only a parcel edit. Each source lot and its building are recorded as deleted with the engine first, then each replacement polygon is added, and only when every one of those commands has been accepted are the old objects removed. If the engine is busy, the tool keeps retrying rather than leaving you with deleted lots and no replacements.

Massing then re-resolves for every new lot. A replacement building does not inherit the storey count of the lot it came from: the add command carries no height, so each one starts at the lane's default of around three storeys and the massing type resolves the rest — 3.5 m per storey, or a 6 m ground floor for Mixed Use. Set the count you want afterwards with the floors arrow or the Floors field, which is what massing covers.

A dressed city does not follow along by itself. Changing lots changes the geometry the theme was linked onto, so the city needs re-dressing — see re-dressing and what survives a redress.

How the engine splits a region into lots

The automatic subdivision is a property of the region, not of the lot. Select a region in Regions mode (Alt+3) and the parameters column draws the region's whole chain in order: Land Use, Massing Type, Subdivision Method, Setback Mode, Lot Settings and Building Height. Pick Residential or Commercial for Land Use — Parks & Open Space stops at a Park Type, and Empty Block draws the boundary and nothing else. Setback Mode appears only for the methods that actually cut lots, because a setback needs a lot edge to measure from.

Subdivision Method is the one that decides whether there are lots at all. It is a dropdown with four entries, listed in this order:

Lot Settings under it changes with the method. The setbacks and a Lot Elevation Mode row (Preserve Slope, Minimum Elevation, Maximum Elevation, Average Elevation) come first, then the chosen method's own numbers. Pick Footprint Map and the section says so instead: “Footprint Map places buildings from a 2D map clipped to the region, so there are no lot constraints.” Straight Skeleton is the method whose fields talk about lot size directly — after Group Angle, Dissolve Angle and Align Offset it offers:

The full set of knobs behind each split algorithm, and how they interact with the rest of generation, is on generation parameters.

• —Splitting is per region, so two regions in the same city can split different ways.
• —Footprint Map skips lots entirely — there is nothing for Lots mode to select inside a region set that way.
• —Hand edits sit on top of the algorithm: a merge is kept across re-splits, a loop cut is kept only while the region keeps the shape it was cut from.