Terrain Calculator — Scenic Material Quantities
Estimate plaster, foam, sand and scenic materials needed for terrain features on your diorama base.
Extra material for offcuts and mistakes
How We Calculate This
The calculator estimates terrain material volume based on your base area, maximum terrain height and a coverage factor for the terrain type.
Formula
- Foam fill volume = Base area × Max height × Coverage factor
- Flat terrain uses ~10% fill, rolling hills ~30%, rugged ~50%, urban ruins ~40%, trenches ~35%
- Plaster weight = volume × density. The default 1.2 g/cm³ assumes lightweight modelling filler or microsphere-loaded paste. Solid cured plaster of Paris is heavier at ~1.5–1.7 g/cm³ — raise the Plaster Density advanced option if you are mixing real POP, or it will under-order weight.
- XPS foam sheets are counted from the fill volume against a real sheet volume (standard 600×600mm hobby sheet × your chosen thickness), and floored at the number of stacked layers needed to reach the terrain height — so a tall, narrow build is never under-counted.
- PVA and sand/scatter figures (0.15 ml/cm² and 0.3 g/cm²) are rule-of-thumb basing rates and vary with how thickly you texture.
Frequently Asked Questions
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Last updated: February 2026
All calculations are estimates. Always verify quantities before purchasing materials.