Assembling and Finishing Terrain Models

Dry-fit before anything else

1. Lay out every tile by its label on a flat surface, base down, without glue.
2. Check the seams by running a fingertip across each join. A step means one tile sits higher (a warped tile or a thicker base) or an edge has a lip (elephant's foot on FDM).
3. Fix edges first. Trim or sand a bottom lip off the edge of the tile, not the landscape. If a tile is warped enough to rock, fix the warping and reprint it rather than forcing it flat with glue.
4. Check connectors. If you used dowels, plugs or snap connectors (PrusaSlicer's cut tool can generate all three), test each joint dry. A tight pin can push tiles apart at the top.

Joining tiles

Two approaches, chosen by how flat and accurate your tiles are:

• Edge to edge. Glue tile faces directly. Fastest, but every tile has to be flat and square, and the seam takes all the load.
• On a backing board. Glue every tile down to a flat, rigid board and to its neighbors. The board takes the load and holds the set flat, which makes small differences between tiles easier to manage. Formlabs notes that straight cuts without aligners need each part positioned by hand until the adhesive sets, so work one tile at a time from one corner.

Adhesive choice depends on the material. Formlabs, writing about resin parts, describes 5 to 30 minute epoxy as giving the strongest bond for large parts with time to adjust, cyanoacrylate for small and medium parts on a clean surface, and mechanical fastening for parts that must come apart. For FDM plastics and for which glue suits which material, see gluing and joining parts. Whatever you use, follow the adhesive's own label and SDS for gloves, eye protection and ventilation.

Filling and sanding seams

On terrain, the landscape surface is the detail. Sanding across it flattens ridges and fills valleys, so work only on the seam:

1. Fill the gap in thin layers rather than one thick blob. Formlabs suggests automotive putty in thin layers for joined parts (or resin cured with a UV pen on resin parts).
2. Sand lightly after each layer dries, keeping the paper on the seam. Formlabs gives about 150 grit to level seams and about 320 grit wet sanding to remove layer lines Starting point.
3. Where the seam crosses a slope, shape the filler to follow the slope rather than leaving a flat band.

Fillers and sanding dust carry their own hazards: follow each product's SDS, and see filling and priming and sanding 3D prints.

Priming

Formlabs' preparation steps: wash away dust with a toothbrush and water, wipe with a tack cloth in long, gentle strokes, then spray primer in short, rapid strokes 6 to 8 inches from the part, in thin coats Starting point. Primer shows where more sanding is needed. On terrain, the first primer coat is also where stair-steps and leftover seams become obvious: decide then whether to fill more or accept them.

Keep primer coats thin. Thick coats pool in valleys and soften fine detail, the opposite of what a terrain model needs. Formlabs lists gloves and a mask for priming; the primer's own label and SDS set the PPE and ventilation, so read them.

Painting

Painting methods, paint types and their safety steps are in painting 3D prints. For terrain specifically:

• Work by elevation. Lowlands, slopes and high ground read clearly when color follows height, as on a printed relief map. Paint the lowest areas first and work upward.
• Water last. Rivers and lakes sit in the lowest ground; paint them after the land so the edges stay crisp.
• Seal it if the model will be handled, using a product compatible with the paint underneath; check both labels.

Edges and display

The vertical sides of each tile show the terrain profile as a cross-section. On an edge-to-edge set, the outer sides can be sanded flat and painted a single color, or left as printed. A board slightly larger than the map gives a border for a title, scale and, if the model is exaggerated, the exaggeration factor (see vertical exaggeration).