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RED+
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Lighting

Show Lightmap Density

Show Lightmap Density draws the outline of every lightmapped face in the Free Look (perspective) view, coloured by how many lightmap texels the face gets per unit. Use it to find surfaces whose baked lighting will look blurry before you look at a bake.

Where to find it

  • View, Show Lightmap Density (RF+)
  • RED+, Show Lightmap Density (RF+)

The command is a toggle. Both menus show a check mark while it is on. It is off each time the editor starts.

Reading the colours

The density is the number of lightmap texels per world unit that RED gave the face's lightmap surface. Where the surface's two directions differ, the lower value is used.

ColourTexels per unit (default bands)
Redless than 2
Orange2 up to 4
Yellow4 up to 8
Green8 up to 16
Cyan16 or more

A face exactly on a boundary takes the higher band, so a face at 4 texels per unit is yellow. The bands are the same on every map, so a colour always means the same density.

The lightmap detail setting caps how many texels one surface can have along each side. A large floor or wall is held at that cap, so its texels are spread over more units and it shows a lower density. See Lightmap detail and file size.

If a bake reports that large flat areas have fewer texels per unit than the rest of the level, because the level needs more lightmap surfaces than RED allows (32,767), those areas show in a lower band.

What it outlines

  • Only the Free Look view shows the overlay.
  • Only the outlines are drawn. The faces are not tinted.
  • Faces without a lightmap and portal faces are not outlined. RED gives no lightmap to faces that are Full Bright when it lays out the lightmaps.
  • In Render Using Portals and Render Current Room Only, only faces in the rooms that mode draws are outlined. In Render Everything and Render Nothing (Except brushes), every lightmapped face is outlined.

Changing the bands

Add density_overlay_thresholds to the [editor] section of redplus.ini in the RED+ folder. The file already has that section.

[editor]
density_overlay_thresholds=2,4,8,16
  • Give four numbers separated by commas, with no space before a comma. Each must be larger than the one before, and the first must be above 0. They are where orange, yellow, green and cyan begin.
  • If the value is missing or not valid, the default bands are used.
  • RED+ reads the value once per session. Restart the editor after you change it.

See redplus.ini and Where settings live.