How To - Working with Collision Boxes in Dungeon Alchemist

Step-by-step

1. 1

   Pick the right collider type for the shape

   Screenshot

   Collider type picker showing Box / Cylinder / Ring / Basket options

   Start by matching the collider primitive to the silhouette of your asset. Box for rectangular props, Cylinder for round-sided objects, Ring for hollow tubes, Basket for open containers. Picking the wrong primitive forces you to over-scale and creates dead space around the mesh.

   Do

   • Use Box for chests, crates, tables, walls.
   • Use Cylinder for barrels, columns, round pedestals.
   • Use Basket for pots and open baskets that need contents to sit inside.
   • Use Ring for open tubes and rims where the center should be empty.

   Don't

   • Wrap a round barrel in a Box collider — corners will block placement.
   • Use Cylinder on tiny props where a Box is cheaper and cleaner.
   • Use Basket when nothing is meant to be placed inside.
2. 2

   Hug the mesh — minimize dead space

   Screenshot

   Box collider tightly hugging a mesh from front / side / top ortho views

   Scale each collider so it sits as close to the mesh surface as possible. Empty space between the mesh and its collider is the number one cause of assets that "feel wrong" — they refuse to stack, snap, or sit next to walls the way players expect.

   Do

   • Check the fit from Front, Side, and Top orthographic views.
   • Use the side handles to nudge each face in until it just touches the mesh.
   • Split a complex shape into multiple smaller colliders rather than one oversized box.

   Don't

   • Leave a single giant box around an irregular asset.
   • Rely only on the perspective view — it hides gaps.
   • Scale from the Object GUI corners; use the collider face handles instead.
3. 3

   Get the stackable top surface right

   Screenshot

   Box collider with lightly tinted stackable top surface highlighted

   A Box collider's top face becomes a stackable surface when it is wide enough and has no rotation. That tinted top is what lets players drop candles on tables, books on shelves, and minis on platforms. If the top is tilted or too narrow, stacking silently breaks.

   Do

   • Keep the top face flat (no X or Y rotation) whenever stacking is expected.
   • Confirm the light tint appears on the top face — that means it's stackable.
   • Disable the surface from the expanded menu if you deliberately don't want stacking.

   Don't

   • Rotate a Box collider on its side and expect the top to still be stackable.
   • Shrink the top face below the width needed for the smallest asset you want to stack.
4. 4

   Stack multiple colliders for complex shapes

   Screenshot

   Chair asset with multiple stacked colliders (seat, backrest, legs)

   Chairs, staircases, and L-shaped furniture need more than one collider. Duplicate a collider using the icon at the base of the GUI frame and position each piece to cover a distinct section of the mesh.

   Do

   • Use one Box per major volume — seat, backrest, legs region.
   • Overlap colliders slightly so there are no gaps at seams.
   • Name the intent in your head: 'this one is the seat surface, this one blocks the legs.'

   Don't

   • Force one enormous collider to cover an L-shape — the concave gap becomes solid.
   • Leave a visible slice of mesh with no collider covering it.
5. 5

   Fine-tune with numeric input

   Screenshot

   Expanded collider menu with numeric X / Y / Z fields and surface toggle

   Expand a collider in the side menu with the arrow key to type exact values. This is how you match the game's grid, mirror one collider to another, or line up two assets that need to sit flush.

   Do

   • Type identical values across duplicated colliders for symmetry.
   • Round to the grid unit when you want clean snapping.
   • Use numeric entry to toggle a Box's surface on or off explicitly.

   Don't

   • Drag by eye when two colliders need to be pixel-identical.
   • Leave odd decimal values from a drag when a clean number would do.
6. 6

   Test in-scene before shipping

   Screenshot

   Asset placed in a Dungeon Alchemist scene with props stacked and against a wall

   Place the asset in a real map next to walls, on tables, and with other props on top of it. Rotate it 90° and 180° to confirm the colliders still behave. Collision issues almost always surface the moment the asset meets another asset.

   Do

   • Drop a mini onto every stackable surface to confirm it lands cleanly.
   • Push the asset against a wall and check it snaps flush.
   • Rotate and re-test — bad rotation on a collider only shows up at certain angles.

   Don't

   • Ship without in-scene testing just because the Blender preview looked fine.
   • Ignore small gaps 'players won't notice' — they always do.