Every brush entity compiles into its own NIF, and its properties decide what goes into that NIF beyond the geometry: how it is lit, how it blends, how its textures are sampled and animated, and how its nodes are arranged. Worldspawn takes them too, for the map’s main mesh.
Everything here is optional. Leave a property unset and the compiler uses the NIF default, which
is what an ordinary wall wants. The definitions live in Nif.fgd.
For geometry that needs these properties but no game record of its own, use nif_geometry: it
compiles to a plain static, like world_Detail.
Material#
Applied to the whole entity.
| Property | Effect |
|---|---|
Material_Diffuse_color | The surface color under light. |
Material_Ambient_color | The surface color under ambient light. |
Material_Emissive_color | Light the surface gives off itself: glowing runes, lava, a lit window. |
Material_Specular_color, Material_Glossiness | Highlights, and how tight they are. |
Material_Alpha | Opacity, from 0 (invisible) to 1. Needs blending, below, to show. |
Transparency#
Blending mixes the surface with what is behind it; testing cuts pixels out entirely. Use blending for glass and smoke, testing for leaves, grates and anything with hard holes.
| Property | Effect |
|---|---|
Material_Alpha_UseBlend | Turn alpha blending on. |
Material_Alpha_BlendSourceMode, Material_Alpha_BlendDestinationMode | The blend equation. Source Alpha with One Minus Source Alpha is ordinary transparency; Source Alpha with One is additive glow. |
Material_Alpha_TestEnable | Turn alpha testing on. |
Material_Alpha_TestFunction, Material_Alpha_TestThreshold | Which pixels survive the test. The threshold is 0 to 255; anything else is ignored and the default used. |
Material_Alpha_NoSort | Skip sorting this object’s triangles. Faster, and wrong for overlapping transparent faces. |
Texturing#
| Property | Effect |
|---|---|
Nif_Texture_ApplyMode | How the texture meets the vertex and material color: Replace, Decal, Modulate (the usual), Highlight. |
Nif_Texture_FilterMode | Nearest for crisp pixel art, Trilinear for everything that should not shimmer at a distance. |
Nif_Texture_ClampMode | Wrap to tile the texture, Clamp to stop it at the edge, per axis. |
Nif_Texture_DarkMap, Nif_Texture_DetailMap, Nif_Texture_GlossMap, Nif_Texture_GlowMap, Nif_Texture_BumpMap | Extra texture slots, by path. |
The dark map slot is where baked lighting goes. Set Nif_Texture_DarkMap and your texture wins
over the lightmap for that entity; the compiler says so when it happens.
Moving textures#
Set Nif_UV_Mode to Scroll, then Nif_UV_U and Nif_UV_V to how many texture widths per
second the texture moves along each axis: water, lava, a conveyor of doom. The compiler works out a
loop length that ends on whole tiles, so a wrapped texture never visibly jumps back.
Set it to Oscillate for a texture that sways back and forth instead: seaweed, a heat shimmer, a
banner in a draft. Nif_UV_U and Nif_UV_V are then how far it swings each way, in texture widths,
and Nif_UV_Period is how many seconds one full swing takes. Oscillate needs a period; without one
the compiler warns and leaves the texture still.
Structure: groups and links#
Some nodes wrap geometry rather than decorate it. Place these as point entities inside a TrenchBroom group, and they wrap every brush in that group:
| Entity | Wraps the geometry in |
|---|---|
nif_node_billboard | A billboard: the geometry turns to face the camera, pivoting at the marker. Nif_Billboard_Mode says how: Always Face Camera (the default), Rotate About Up for things that stay upright, Rigid Face Camera, or Always Face Center. Those four are all a Morrowind NIF can hold, and OpenMW draws the last one as Always Face Camera. |
nif_node_sort_adjust | A sort node: Nif_Sort_Mode Inherit, Off or Subsort, for transparent geometry that sorts badly. |
nif_node_collision_root | Nothing visible: it moves the mesh’s collision node (RootCollisionNode) to the marker, without moving the collision itself. One per mesh; any more are ignored with a warning. |
Markers in nested groups nest in the same order: the outer group’s node contains the inner group’s. Where a marker sits matters, because it is the node’s pivot.
To say which node goes inside which, name one with Nif_LinkName and point the other at it with
Nif_Target. A brush entity can set Nif_Target too, to hang its geometry under a named node
instead of the innermost one. TrenchBroom draws these links as lines. Outside any group a target is
looked up across the whole map; inside one, only within that group’s chain.
The compiler refuses, with a message naming the problem:
- a
Nif_Targetthat matches noNif_LinkNamein its scope, or matches more than one; - two markers with the same
Nif_LinkNamein one scope; - targets that loop back on themselves.
A map with no groups and exactly one nif_node_collision_root is a special case: that marker
applies to all ungrouped geometry, since there is nothing else it could mean.
Rotation#
mangle is an entity’s rotation: pitch, yaw and roll in degrees, which TrenchBroom writes as you
rotate the entity, so there is rarely a reason to type it. The compiled reference gets the same
rotation, and a brush entity’s mesh is built along the entity’s own axes, so the object faces the
way it does in the editor and turns about the same axes in game. That matters to anything that
uses its axes: a billboard inside it, a door from the catalog swinging on its hinge, an item picked
up and dropped again.
For TrenchBroom to keep mangle, leave Update angle property after transform on in the Rotate
tool; it is on by default. Brushes rotated with it off are placed as they look, but the object’s
own axes stay the map’s.