Getting started

Build, adjust, then edit polygons

• Choose a primitive: Box, Plane, Sphere, Cylinder, Cone, or Prism. Its button enters viewport drawing mode.
• Draw or enter values: draw the object in a viewport, or use Create at origin with the displayed parameters. The next guide page explains each shape.
• Adjust the primitive: select it and change its dimension or segment spinners. Only parameters supported by that shape appear.
• Convert to Editable Poly: freeze the current primitive mesh to unlock Vertex, Edge, and Face selection. Undo can restore the primitive parameters.
• Right-click menu: right-click in a viewport for Select, Move, Rotate, Scale, and tools for the current subobject mode. The lower section switches Object/Vertex/Edge/Face on Editable Poly objects, or offers Convert to Editable Poly for primitives. Orange highlights hovered or keyboard-focused labels. Click outside or press Escape to dismiss.
• Tool shortcuts: Q selects, M moves, R rotates, and S scales. Use Key bindings before Getting Started to change shortcuts or assign modifier combinations. Lighting is in each shaded viewport’s lightbulb flyout. The shading dropdown has a checkbox beside Wireframe to control edges over shaded surfaces. New primitives reset to dimensions of 1 unit, one segment per box/plane dimension, 6 sides for cylinders and cones, 3 sides for prisms, and 12 segments × 12 rings for spheres. Cones keep a zero top radius for a pointed tip.
• Numeric spinners: click an arrow for one step, or hold and drag up/down to adjust continuously. Dragging does not add a click step. You can also type a value.
• Save project: keep an .autumn3d file to preserve parametric objects, converted meshes, layers, and editor settings.

Find your controls

• Left panel: layers, object names, color, and opacity.
• Right panel: creation parameters, transforms, selection levels, modeling operations, and pivot controls. Click a rollout heading to collapse it.
• Guide pages: use Previous / Next or the topic menu to jump directly to a tool.
• Hover tips: short explanations follow the cursor over buttons and tools.
• Existing models: older projects and imported OBJ geometry remain editable meshes; they do not gain primitive parameters.

Primitives: draw & adjust

Draw a primitive in a viewport

• Box: press at the first corner and drag to the opposite base corner. Release, move the mouse up/down to raise or lower the height, then click to finish.
• Plane: drag between two opposite corners and release to finish.
• Sphere: drag outward from its center to set Radius; release to finish.
• Cylinder / Prism: drag the base radius and release. Move up/down to set Height, then click to finish. Prism uses a regular polygon base; Sides = 3 makes a triangular prism.
• Cone: drag its base radius and release. Move up/down for Height and click, then move right to set Top radius and click again. Top radius = 0 produces a point.
• Construction plane: Top and Perspective draw on the ground plane; Front and Side use their corresponding view planes. Grid snap applies to base sizing and height.
• Finish or cancel: drawing mode stays active for another object. Stop drawing or Escape exits it; an unfinished preview is discarded. Right-click also exits drawing without opening a menu.
• Create at origin: creates a new primitive at the world origin using the current parameter values.

Adjust the selected primitive

• Box: Width, Length, Height, and independent Width / Length / Height segment counts.
• Plane: Width, Length, and Width / Length segment counts.
• Sphere: Radius, Segments around the sphere, and Rings from pole to pole. There is no separate Number of sides field.
• Cylinder / Prism: Radius, Height, Sides, Height segments, and Cap segments.
• Cone: base Radius, Top radius, Height, Sides, Height segments, and Cap segments.
• Live controls: only relevant fields appear. Dimensions reshape the primitive; segment spinners change subdivision without moving the object or its pivot. Parameter edits support Undo/Redo and are saved with the project.

Convert when ready for subobject modeling

• Convert to Editable Poly: preserves the current shape and transforms, removes primitive parameters, and unlocks vertex, edge, and face tools.
• After conversion: use polygon modeling operations to change the mesh. Undo conversion to recover its parameters if that undo step is still available.
• Preview safety: unfinished primitive draws are excluded from autosave, project files, and OBJ export. Finish or cancel a draw before continuing other edits.

Selection & deletion

Select exactly what you need

• Plain click: select only the clicked vertex, edge, or face.
• Ctrl+A / Cmd+A: select every vertex, edge, or face at the current subobject level.
• Shift-click: add a component. Clicking one already selected keeps it selected.
• Ctrl-click / Cmd-click: remove only the clicked component.
• Select tool: drag a dotted rectangle over objects or components. Dragging empty space in other tools also starts a marquee.
• Shift + marquee: add. Ctrl/Cmd + marquee: subtract.
• Show back-face subobjects: in Selection Level, turn this off to hide rear-facing vertices, edges, and faces and exclude them from picking and box selection. Works in wireframe and shaded views; overrides Select through for rear components.
• Select through: include back-side or obscured components. Without it, shaded views use visible surfaces for picking.

Delete and recover

• Delete / Backspace: remove selected objects or components. The toolbar also offers Delete.
• Face deletion: leaves a hole. Deleting vertices or edges also removes their incident faces.
• Undo / Ctrl+Z: recover edits and deleted geometry. Redo / Ctrl+Shift+Z: restore an undone edit.
• Escape: cancel an active drag; otherwise clear selection or cancel a pending tool operation.

Transforms & precision

Move, rotate, and scale

• X / Y / Z handles: drag along one axis. Rotation uses colored rings.
• XY / XZ / YZ panels: move or scale on two axes.
• Center square: free movement in the viewport plane, or uniform scaling.
• Grouped transforms: select several components, then drag the gizmo to keep the group selected.
• Coordinates: objects use world coordinates; vertices and edges use object-local coordinates. Face rotation aligns X/Y to the surface and Z to its normal.

Numeric values and snapping

• Transform fields: update with edits. Type exact X/Y/Z values, then Enter or Apply. Position is absolute; rotation is in degrees; scale 1 is the original factor.
• Grid snap: enable it and choose 0.1, 0.25, 0.5, 1, or 5 units.
• Shift + Move: lock the dominant movement axis. Release Shift to move freely.
• Shift + Rotate: snap the angle change to 5° increments. Shift-click away from the gizmo still adds to selection.

Viewports & display

Navigate the model

• Top / Front / Side: orthographic views for precise editing. Perspective: inspect depth and shape.
• Alt + drag in Perspective: orbit. Middle-button drag: pan. Mouse wheel: zoom.
• Frame all / F: fit visible objects into the viewports.
• Viewport maximize button: enlarge that view. Orthographic views: restore the four-view layout.
• FOV: click the Perspective header button and enter 15–120 whole degrees. Lower values give a narrower view.

Shading and work lighting

• Shading menu: choose Wireframe, Flat shaded, or Smooth shaded independently for each viewport.
• Show polygon edges: overlay topology on shaded surfaces. Translucent layers also show dim rear edges; opaque geometry still blocks them.
• Work light: choose Flat or Smooth shading to reveal that viewport’s lightbulb. Its flyout controls Work light independently for that view. These display settings never export.
• Mesh statistics: show polygons, quads, rendering triangles, and vertices.

Vertex tools

Reshape and combine vertices

• Create face: activate Create face, then click four boundary vertices in order. Each fourth click creates a quad; continue with another four vertices, or click Create face again to exit; existing vertices and edges are shared, keeping the patch connected. Each selected boundary edge must have one attached face.
• Chamfer vertices: activate Chamfer vertices, then drag the diamond viewport handle up/down or edit Chamfer amount. Apply commits; Cancel discards and exits. Vertices split along their incident edges. Each corner is left open; new boundary vertices remain selected. Undo restores the original corners.
• Collapse: merge selected vertices at their average local position.
• Weld vertices: merge selected vertices into nearby groups using the weld threshold. Each group merges at its average position; vertices outside the threshold remain separate.
• Target weld: drag a vertex onto another joined to it by an existing edge. The source fuses into the target position.
• Align X / Y / Z: set that coordinate to the selected vertices’ average to form aligned rows or planes.
• Converge: overlap selected vertices at their center without welding them.
• Rejected merges: the editor blocks several degenerate or non-manifold results rather than applying them.

Cut new connections

• Cut tool: click a starting vertex, then an unconnected endpoint. A dashed preview follows the cursor.
• Crossing polygons: the cut follows a connected surface corridor in the active viewport, including folded surfaces.
• Crossed edges: receive shared intersection vertices; affected polygons split into new faces.
• Cut selected pair: use exactly two selected vertices and the active viewport.
• Escape: cancel the pending start. If no continuous cut is found, try another view or shorter cuts.

Edge tools

Select and connect topology

• Select loop: start with one edge. Border edges follow the connected open boundary; interior loops follow regular quad topology.
• Loop limits: interior loops stop at irregular vertices or non-quad faces. Separate boundaries stay separate.
• Chamfer edges: activate Chamfer edges to open the controls and enable viewport dragging. Drag a highlighted edge or the diamond viewport handle up/down to adjust the amount. Release keeps the preview; Apply commits and deactivates Chamfer. Cancel or clicking Chamfer edges again discards the preview.
• Chamfer settings: adjust Amount and Segments in the open rollout. One segment creates a flat bevel; 2–8 segments round it. Connected corners are joined; open borders add an inset strip. Apply commits one undoable edit; Cancel or Escape restores the mesh. Keep amounts small enough to avoid overlap.
• Select ring: follow opposite edges across connected quads.
• Connect midpoints: select two non-touching edges per affected face to split between their midpoints. Select a ring to connect across several quads.

Extrude an open border

• Extrude border edges: select one or more open edges, then activate the tool.
• Arrow handle: drag freely in the viewport plane. New quad strips connect the original border to the new outer edges.
• Shift while dragging: lock the dominant local axis. Releasing Shift restores free movement.
• Outer edges: remain selected for another extrusion. Shared endpoints remain connected.
• Restrictions: edges must have one attached face. Drag outward rather than along the selected edge. Escape cancels; Undo restores.

Face tools

Add depth and detail

• Extrude: select faces, activate Extrude in Face Operations, then drag the selected face or arrow handle. Connected selected faces extrude as one welded region with boundary walls; separate islands extrude independently.
• Bevel: connected selected faces form one welded region. Drag vertically for height and horizontally for inset; side walls are created only around the region’s boundary. Disconnected selections bevel separately. Drag the handle or a selected face to bevel the full selection. Very large insets or complex intersections may need smaller steps and manual cleanup.
• Numeric distance: enter Distance / inset and use Apply numeric distance.
• Quad tessellate: split each selected quad into four. Neighboring faces share new edge points and may become n-gons; triangles and n-gons are skipped.
• Attach objects: in Object Operations, select an Editable Poly, activate Attach object, then click the other object in a viewport or its layer-list row. The clicked object merges into the selected object without moving. Primitives attached this way become polygon geometry. Live symmetry on either object is baked into the merged geometry. The base object keeps its name, pivot, transforms and layer. Escape or a second click on Attach exits.
• Weld after attaching: in Object Operations, set Weld distance (world units; 0 welds exact overlaps) and click Weld overlapping vertices to check all vertices. For only a subset, use Vertex mode, select the seam vertices and Weld vertices. Attach does not remove interior faces or perform a Boolean union; remove unwanted touching cap faces before welding a seam. Unsafe welds are rejected. Attach and Weld each support Undo.
• Detach faces: select faces and click Detach faces to move them into a separate Editable Poly object. Connected faces stay welded within the new object. Position, transforms, layer, and face winding are preserved. The source is left open without a cap; if all faces are detached, the empty source is removed. The new object is selected in Object mode. Undo restores both.
• Delete faces: open a hole without adding a cap. Use border extrusion to extend its boundary.

Normals and edit safety

• Flip normals: activate the button, then click faces to reverse their normals. Click the button again to exit. Each flip supports Undo. Shift-click adds to selection; Ctrl-click removes.
• Unify normals: select faces, then Unify normals. Connected selected faces are made consistent with the majority winding; a cube with five outward faces and one inward face becomes outward. Ties retain the first selected face’s winding. Unselected faces stay unchanged.
• Recalculate outward normals: repair winding on closed geometry. Open surfaces have no enclosed outside and remain two-sided.
• Interactive edits: each completed extrusion or bevel drag is one undo step. Escape restores the pre-drag mesh.
• Model checkpoints: save projects before substantial topology changes. This remains a developing modeler, not a complete production modeling suite.

Object pivot

Choose what the editor affects

• Affect pivot only: move the transform origin without moving the visible geometry.
• Affect object only: on an Editable Poly, move, rotate, or scale geometry while the pivot stays fixed. Convert a primitive first to use this mode.
• Visual editing: use the gizmo. Numeric editing: use the rollout coordinates, which describe the pivot or object center depending on the mode.
• Recenter in pivot mode: preview the pivot at the object’s world bounds center.
• Recenter in object mode: preview the object’s center on its fixed pivot.

Apply, cancel, and continue

• Apply: commit the preview and turn both affect buttons off. Pivot fields and Recenter lock until you re-enter a mode.
• Cancel: restore the previous geometry and pivot. Escape cancels a drag or pending preview.
• After Apply: ordinary object transforms use the applied pivot. Committed origins survive project saving and Undo/Redo.
• Unapplied previews: do not enter project files or OBJ exports.

Layers & files

Organize objects with layers

• Expand / collapse: click the small arrow beside a layer name to show or hide its object rows. Collapsing keeps the objects visible in the viewports and preserves selection. The collapsed state is saved with the project.
• ＋ New layer: create and name a layer. Click its name to make it the active layer for new objects.
• Trash can: delete the active layer and move its objects to a remaining layer. The objects are kept; Undo restores their assignments. The last remaining layer cannot be deleted.
• Go to layer: use the dropdown to expand a layer, select its first object, and bring that object row into view. This does not move objects between layers. Empty layers clear the object selection.
• Assign objects: drag an object row onto the destination layer header.
• Eye icon: hide or show every object on that layer.
• Rename a layer: double-click its name. Rename an object: double-click the object name, then press Enter or click away to commit; Escape cancels.
• Object state: a faint label at the bottom right of each object row shows Object for a parametric primitive, or Editable Poly after conversion.
• Select an object: click its row. A brighter layer-colored fill and orange outline mark selected objects.

Layer color and viewport opacity

• Color chip: click the small chip at the right of a layer header to open its appearance controls. Choose a color to apply to every object on the layer; click Done to close.
• Opacity slider: drag left for more transparency or right for more opacity. Layer opacity affects the objects in Flat and Smooth shaded viewports: 100% is opaque, lower values are translucent, and 0% makes the layer’s geometry invisible.
• Rear edges: translucent objects can show dim backside wireframe edges when the checkbox beside Wireframe is enabled in that viewport’s shading dropdown.
• Layer-colored rows: the dark fill, matching text and border, and bright right-side strip follow the layer color. These row colors stay fully visible when you lower viewport opacity.
• Save your setup: layer names, assignments, visibility, color, and opacity are preserved in project files and browser autosave.

Save, open, import, and export

• Right-click menu: right-click in a viewport for Select, Move, Rotate, Scale, and tools for the current subobject mode. The lower section switches Object/Vertex/Edge/Face on Editable Poly objects, or offers Convert to Editable Poly for primitives. Orange highlights hovered or keyboard-focused labels. Click outside or press Escape to dismiss.
• Tool shortcuts: Q selects, M moves, R rotates, and S scales. Use Key bindings before Getting Started to change shortcuts or assign modifier combinations. Lighting is in each shaded viewport’s lightbulb flyout. The shading dropdown has a checkbox beside Wireframe to control edges over shaded surfaces. New primitives reset to dimensions of 1 unit, one segment per box/plane dimension, 6 sides for cylinders and cones, 3 sides for prisms, and 12 segments × 12 rings for spheres. Cones keep a zero top radius for a pointed tip.
• Numeric spinners: click an arrow for one step, or hold and drag up/down to adjust continuously. Dragging does not add a click step. You can also type a value.
• Save project: choose a destination for .autumn3d. It preserves primitive types and parameters, converted geometry, transforms, pivots, layers, and editor settings.
• Open project: select an .autumn3d file to replace the workspace. Save your current work first if needed.
• Import OBJ: select a file to add polygon geometry for continued editing. Export OBJ: choose a destination for the scene’s geometry, including hidden layers and live symmetry.
• File pickers: saving/exporting require browser support for the system Save As picker. If it is unavailable, the app explains the limitation and does not auto-download.
• Autosave / recovery: use the Autosaves button for earlier snapshots (details on the Copies, snapping & recovery page). Each tab has its own independent workspace, preserved when that tab refreshes. Duplicating a tab may copy its initial workspace, but subsequent edits and autosaves remain independent. Save a project file before closing a tab; tab autosave is not a permanent backup. FBX, rigging, and animation are not implemented. UV mapping and materials are described on the final guide page.

Finish borders & surfaces

Find and close open borders

• Select border: in Edge mode, select an open edge, then Select border to expand around its loop. With nothing selected, it selects all borders. Interior edges are rejected.
• Cap border: select a border loop (or one seed edge), then Cap border. It creates a welded polygon cap. Multiple selected loops are capped separately; this does not create a single cap with an inner hole.
• Bridge borders: select at least one edge on each of two separate border loops on the same object, then Bridge borders. Attach separate objects first. The tool aligns the loops and creates quads, with triangles where vertex counts differ.
• Bridge limits: choose loops that should connect without crossing. Branching borders, loops sharing vertices, duplicate faces, and non-manifold results are rejected. Twisted or intersecting geometry may need manual cleanup.

Inset and extrude a connected region

• Inset faces: select faces, enter Inset distance, then Inset faces. Connected faces stay welded and the surrounding strip is created only at the boundary; no height is added.
• Connected Extrude / Bevel: drag a selected face or the tool handle. Shared selected edges stay internal; side walls follow the selection boundary. Disconnected face islands are handled separately.
• Closed elements: Extrude on a fully selected closed element offsets its vertices along averaged normals. Inset and Bevel with an inset need an outside boundary.
• Selection helpers: Grow adds neighboring components, Shrink removes the selection boundary, and Select connected element expands from the current selection through connected vertices, edges, or faces. These are selection actions, not geometry edits.

Control hard and soft shading

• Surface Smoothing: in Object Operations, enter an angle from 0–180° and Apply auto smooth. In Smooth shaded viewports, neighboring face normals blend when their angle falls within that limit.
• Hard edges / Smooth all: apply 0° or 180°. These apply to selected objects; they do not add or remove geometry. Flat shaded viewports remain flat.
• Cylinder example: start with 45° to smooth the sides while keeping cap transitions crisp. Smoothing angles save in projects, and OBJ export writes the resulting normals.
• Undo and feedback: each committed topology or smoothing operation is undoable. Invalid operations explain the reason, and the latest operation stays in the bottom status area.

Copies, snapping & recovery

Duplicate objects and components

• Duplicate Selection rollout: select objects or Vertex/Edge/Face components. Set Copies (1–100) and the X/Y/Z world-space offset per copy, then Duplicate selection. Ctrl+D uses the same settings unless rebound.
• Shift-drag Move: hold Shift as you begin dragging a Move handle to make copies using the rollout count and the distance you drag. The original remains in place. Shift also constrains the movement to a dominant axis.
• Component copies: duplicated faces keep their internal shared vertices but separate from the source. Vertex copies are standalone points; edge copies are standalone edges. Use Attach, Weld, Create Face, or other modeling tools to join geometry as needed.
• Selection and Undo: new copies become selected. The entire duplication is one Undo step, including Shift-drag copying.

Snap precisely and frame your work

• Geometry snap: enable it in the top toolbar and choose Vertex, Edge, or Face. While using Move, the moved selection snaps to visible target geometry. A blue marker shows the snap position.
• Move anchor: dragging near a selected vertex uses that vertex as the anchor; otherwise the selection center is used. Vertices and edges snap when the anchor comes within about 14 screen pixels of a target. Face snap projects onto the surface under the anchor.
• Constraints: geometry snapping respects the chosen move axes and Shift constraints. It does not weld anything. Grid snap remains a separate control. Hidden layers are excluded; Select through permits rear targets.
• Frame selected: select objects or subobjects, then Frame selected (Shift+F by default). All viewports fit that selection. Frame all (F) still fits the scene.

Recover earlier autosaves

• Autosaves button: open the recovery list in the top row. Choose a dated snapshot and confirm to restore it. Your current workspace is kept as another recovery snapshot before restoration.
• History: each tab keeps up to 20 snapshots, with additional periodic snapshots during editing. Storage limits can reduce the available history. Current autosaving takes priority if storage fills.
• Corrupted current autosave: when possible, the app falls back to the newest stored recovery snapshot.
• Permanent backups: recovery history belongs to this tab and is not cloud storage. Save project files before closing the tab or doing substantial work. Separate tabs do not overwrite one another.
• Interrupted tools: Escape, lost pointer capture, and leaving the window cancel incomplete drags so another tool can be used. Releasing a normal drag commits it.

UV mapping & materials

Project a texture onto your model

• UV Mapping button: click the checkered button at the far right of the top toolbar, after Frame all, Frame selected and Maximize view. The right panel switches to a focused UV rollout for the active selected object. Click another object in a viewport or layer list to map it. Click the checkered button again, Back to modeling, or a main tool button to return to modeling. The Materials button beside UV Mapping opens a separate material panel. Both panels keep the modeling rollouts out of the way.
• UV Mapping: the focused panel maps every face of the selected object. Box maps each face along its dominant axis; Planar uses one axis; Cylindrical wraps the sides and projects end caps; Spherical wraps around the selected axis. From view projects along the active viewport.
• Viewport UV handle: enable it, choose Move/Rotate/Scale UVs, then drag the cyan diamond above the selection in any viewport. It edits texture coordinates without moving geometry. Move follows screen horizontal/vertical directions; Rotate and Scale use horizontal/vertical dragging. Toggle it off to resume normal picking. Escape cancels a drag. Numeric controls and the UV editor provide precise placement.
• Axis and placement: choose X/Y/Z, set U/V tiling, offsets and rotation, then Apply mapping. Tiling and U/V offsets update immediately while typing or dragging their spinners, with one Undo step per adjustment. Existing UV island placement is preserved. Apply mapping establishes or replaces the projection on the chosen faces; use it after changing projection, axis or rotation. A checker preview reveals distortion and texture scale. Primitives can be mapped, but map again after changing primitive segments or dimensions for the best result.
• Seams: each face corner has its own UV coordinate. A seam does not split or unweld the geometry. Cylindrical and spherical projections cross the wrap seam continuously; poles and caps may need adjustment or separate mapping.

Edit the UV layout

• Open UV editor: opens the active object's UV layout. Choose Face selection inside the editor to adjust individual faces. Click a face or island; Shift adds, Ctrl removes. Select all selects the faces available in this editor.
• Move / Rotate / Scale: choose a tool and drag the selection. Rotation and scale use the selected UV center. Use numeric U/V offsets, angle and scale with Transform selected for precision. Each completed gesture or numeric action is undoable. Escape cancels an active drag.
• Navigation: wheel zooms around the cursor; middle-drag pans. Reset view returns to the 0–1 tile. The image of the selected face's material is shown behind the UVs when available; otherwise a checker appears.
• Fit 0–1: uniformly fits the chosen UVs into the texture square with a margin. Pack islands places separate UV islands in a grid with padding. Packing is basic and does not equalize texel density or optimize space. Seam marking and relaxed organic unwrapping are not included.

Create and assign materials

• Materials button: beside UV Mapping at the far right of the top toolbar, opens the focused Materials panel. Swatches show material names and colors. The small sphere previews color, image, opacity and roughness. Close with the toolbar button or Back to modeling.
• New material: adds a named scene material. Set its name, base color, opacity and roughness, then Apply material changes. Changes affect every face using that material. Roughness controls a simple viewport highlight, not a full physically based renderer.
• Duplicate / Delete: Duplicate copies the chosen material and its image without assigning it; edits to the copy do not affect the original. Delete asks for confirmation and returns faces using that material to layer color. Both are undoable.
• Objects / Faces: choose the assignment level, then select targets in the viewport or layer list. Face assignment needs an Editable Poly. Select faces using material selects all matching faces on the active Editable Poly, including faces inheriting an object material. The UV Mapping shortcut opens mapping for the active object.
• Assign material: applies the chosen material to selected objects, or selected faces in Face mode. Use layer color removes assignments on the selection. Unassigned faces retain their layer color. Show materials toggles material appearance in shaded views without deleting assignments.
• Load image: choose a PNG, JPEG or WebP. Images are converted to PNG, limited to 1024 pixels per side, and embedded in project files. Image colors multiply base color; use white for the original image colors. Material opacity multiplies image alpha and layer opacity.
• Save and export: projects, Undo and tab autosave preserve materials, images and UVs. Large images can exhaust browser autosave space; save a project file. Export OBJ includes geometry, normals and UVs. Export textured OBJ saves a ZIP containing the entire scene, autumn-model.obj, autumn-materials.mtl and PNG textures. Extract the ZIP together before importing elsewhere. OBJ import reads UVs; external MTL/image loading is not included.
• Topology edits: existing face UVs and materials are retained where possible. New side walls receive a simple projection and inherit a nearby material. Inspect the checker and remap new faces after substantial topology edits.