Modifiers

Modifiers change how the scene looks without adding data of their own. A modifier is not a layer — it carries no dataset, and you cannot download or filter it — but it names the layers, terrain, or buildings it applies to. Two kinds live in the Modifiers section of the Layers panel: clipping cuts, which cut geometry away so you can look inside it, and zones, which colour features by the polygons of another layer they fall inside.

Opening the Modifiers section

The Modifiers section appears below your layers in the Layers panel, as soon as the project has at least one layer. Click its header to expand or collapse it. A count badge shows how many cuts and zones currently exist.

Click + on the section header to add a modifier. The menu offers:

Menu item	What it creates
Clipping cut	A new clipping cut, ready to configure
Zone (pick on map)	Starts zone creation by clicking polygons directly on the globe
Zone (from a layer)	Opens an inline form where you choose the mask layer from a dropdown, without clicking anything on the map

Zone (pick on map) and Zone (from a layer) are disabled if the project has no polygon layer to build a zone from.

Shared row controls

Every modifier row — clipping cut or zone — has the same controls:

• Eye icon — turns the modifier on or off without deleting it
• Double-click the name (or the pencil icon) — renames it inline
• Chevron — expands the row to show its settings
• Trash icon — removes it

Only one row can be expanded at a time across the whole Layers panel — expanding a modifier collapses whatever layer or modifier row was open.

note

Clipping cuts and zones are listed as two separate groups rather than one merged list, because dragging means something different for each: zone rows are drag-ordered (see Which zone wins), and clipping cut rows are not ordered at all.

Clipping cuts

A clipping cut removes part of the terrain, OSM buildings, or a 3D layer so you can see what is underneath or inside it — a half-space plane cut, or a box cut.

Configuring axis, position, range, and which objects a cut applies to works the same way whether you create the cut from the Modifiers section or from the Tools panel. See Clipping Plane for the full walkthrough.

A few things specific to the Modifiers row:

• Targets are shown as chips on the row — terrain, OSM buildings, or specific 3D layers. A cut can target several objects at once.
• A greyed, struck-through chip means another clipping cut already claims that target — only one clipping cut can apply to a given object at a time. Turn off or remove the earlier cut to free it up.
• If no target is selected, the row shows a warning that nothing is being clipped.

Zones

A zone colours the features of one or more layers — or the OSM Buildings tileset — by the polygons of another layer, a drawing, or an analysis result (such as a flood outline or a shadow study). Use it to show which buildings or features fall inside a flood extent, a planning boundary, a construction zone, or any other area of interest.

Creating a zone

You can start creating a zone from any of these doors:

1. Modifiers → + → "Zone (pick on map)" — click the polygons that define the zone directly on the globe, then click the features you want coloured. This is the quickest route when the mask layer is visible on screen.
2. Modifiers → + → "Zone (from a layer)" — pick the mask layer from a dropdown, without clicking on the map. The mask is the whole layer.
3. A polygon layer's Advanced menu → "Color what's inside" — build the zone starting from the layer that defines the area (a zone plan, flood extent, planning boundary).
4. A non-polygon layer's Advanced menu → "Color by a zone layer" — build the zone starting from the layer you want coloured, then pick which zone layer's polygons should colour it. Polygon layers show door 3 instead: from there you pick this layer as what the zone colours.

All four doors produce the same kind of zone, and any of them can also colour the OSM Buildings tileset.

Door 2 has no confirm button: the zone is created as soon as the mask layer is picked, and every later change on that row — what gets coloured, the colour, Inside/Touched — is applied straight away. Doors 3 and 4 need an explicit Color now button: nothing is coloured until you press it, and a later change to the colour or Inside/Touched only takes effect on the next press. Close the form when the result looks right, or delete the zone from its row in Modifiers.

When picking on the map, the mode stays open until you confirm it — click the polygons that make up the mask, then confirm to move on to picking which features to colour, then confirm again. Press Escape at any point to leave without creating anything. Clicking an already-picked polygon or feature removes it, so a mis-click costs one click, not a restart.

tip

Tick Color by attribute while creating a zone to make one coloured group per attribute value, instead of a single flat colour for everything the zone matches.

Match modes

Every zone uses one of two match modes to decide which features count as "inside":

Mode	What it includes
Touched	Any feature that overlaps, crosses, or touches the mask polygon at all — a half-flooded building still counts.
Inside	Only features that fall entirely within the mask polygon.

Change the match mode from the expanded zone row. Changing it re-computes the zone, so it may take a moment on a large layer.

Colour by attribute

When a zone targets the OSM Buildings tileset, you can tell the matched buildings apart by one of their own OpenStreetMap tags — for example building type or use — instead of colouring them all the same. Expand the zone row and use Group by to choose the tag; only tags the matched buildings actually carry are offered. Once a tag is chosen, click any colour swatch in the list to override that value's colour.

Which zone wins where they overlap

Zone rows are drag-ordered. Where two zones colour the same feature, the topmost row in the list wins. Drag a zone row up or down by its handle to change its priority.

Managing a zone

Expand a zone row to:

• Recolour it and adjust its opacity
• Change its match mode
• Add or remove which layers (and OSM Buildings) it colours
• Swap its mask layer, using the dropdown on the row — this asks for confirmation if it would discard an attribute grouping
• Recompute the zone from its current source with the refresh icon
• Fly the camera to the zone's mask

Removing a zone asks for no confirmation — nothing is lost, since a zone's colouring is never written into a layer's own style. Undo the removal from the toast notification that appears.

The zone legend

While a zone is colouring a layer or the OSM Buildings tileset, the Map Legend shows a key for that zone's colours instead of the layer's own colour key. This is visible in shared links and video exports too, since a citizen viewing a public share has no Modifiers panel to read the colours from directly.

Saving in scenarios

Clipping cuts and zones are both saved in scenario snapshots — their targets, colours, visibility, and (for zones) match mode and priority order. Create a new scenario or use Update snapshot to store the current modifiers. Switching to that scenario restores them exactly as they were saved.

warning

If you create or edit a modifier but do not create or update a scenario snapshot, that change is not stored in the scenario.

note

Matching for zones that target OSM Buildings depends on OpenStreetMap building footprint coverage for the area you are studying. In well-mapped urban areas, matching is usually strong; in rural or less-mapped areas, some buildings may be missing or have incomplete footprints.