Projectors

Projectors

A projector paints a texture onto whatever geometry falls inside its volume — a headlight on the road, a lamp pool on a wall, a mark on the ground. It carries no mesh of its own: the game works out as it draws which surfaces the volume overlaps, maps the texture across it and paints them.

Add ▸ 4DS ▸ Projector builds one. Set Frame Type: Visual and Visual Type: Projector on an empty to make one by hand.

The volume

Two units across and one unit deep along local +Y, carried by the frame's own transform — so the object's scale is how big the projection is, and nothing about the shape is stored in the file.

Shape	The volume
Orthographic	a box, the same width all the way through, so the projection is one size however far it reaches
Perspective	the pyramid inscribed in that box, spreading from the frame's own point, so the projection grows with distance

Depth Falloff

How the paint is weighted from the near face to the far one.

Constant	full strength throughout, no depth term at all
Linear	full at the near face, fading to nothing at the far one
Triangular	nothing at either face, full at mid-depth

Tip

A surface sitting exactly at the far face of a Linear projector takes no paint at all — that is the falloff reaching zero, not a fault. If a projector seems to paint nothing, check that what you want painted is inside the volume and not at its very end.

Blend Mode

Additive	adds to the surface, so it can only brighten and black adds nothing. For light: headlights, lamp pools, glows
Alpha Blend	draws over the surface, hiding it where the texture is opaque. For marks: tyre tracks, scratches, decals

The two together make the six mode values a file can carry. Anything else in that byte is read as Alpha Blend with no depth term.

The material

A projector needs a material, and paints its diffuse texture and nothing else. The format keeps a material number and zero is not one, so the export refuses a projector without one, and warns about one whose material writes no diffuse texture — it would draw nothing.

What reaches the paint:

• the diffuse texture;
• the transparency the material keeps in a second image, where it has one — a color key, a truecolor texture carrying its own alpha, or an additive material each settle transparency on their own and the second image is left out;
• the color key, which cuts its own color out of the paint;
• an animated texture, which cycles as it does anywhere else.

What does not: the material's colors, its opacity, its environment map, its switches. None of them reach a projector in game. The color a projector is tinted with is its own, and the format has nowhere to keep it — so it is always full strength.

A projector has no mesh and so no material slot, and never appears in Blender's Material tab. Edit it from Material Settings inside the projector's own panel, and use the + beside the picker to make one set up the way the game reads it.

Seeing it in Blender

The viewport paints the projector onto the surfaces it covers, with the volume shape, the UV mapping, the falloff and the blend the mode asks for, stopping at the first thing in the way. Project Textures in the 4DS Model tab turns it off. It is drawing only — nothing about the model changes either way.

Note

One thing the viewport cannot do: Blender composites an overlay over the scene rather than adding into it, so an Additive projector cannot brighten the surface it lands on. It is drawn with its brightness carried in its opacity instead — black shows nothing, the brightest paint shows fully, and the falloff fades it away. The shape, the texture, the falloff and where it stops are exact; only the brightening is not, which shows on a light surface more than a dark one. Alpha Blend is exact.