DarkRadiant User Guide (2025)

Figure 1. Components of the 2D view

Customising the grid appearance

The appearance of the grid can be customised using the options in the Grid tab of the Edit→ Preferences dialog. Separate styles can be chosen for major and minor grid lines.

Use background image

Master toggle to show or hide the background image.

Image file

Click on the widget to show a file chooser which allows you to find and*select the background image to show.

Opacity

Drag the slider to control the opacity of the image, from fully transparent*(invisible) to fully opaque.

Scale

Adjusts the size of the image.

Horiz. offset

Adjusts the position of the image from left to right.

Vert. offset

Adjusts the position of the image from top to bottom.

Keep aspect

If checked, the image will always be displayed at its native aspect ratio.If unchecked, the image will have the same aspect ratio as the containing 2D view.

Zoom with viewport

If checked, the image will change size as the 2D view is zoomed in orout. If unchecked, the image will always have the same size regardless of the 2D windowzoom.

Pan with viewport

If checked, the image will be anchored in 2D space, and will stay inthe same position relative to the world as the 2D view is panned. If unchecked, the imagewill always have the same position relative to the window, and the world geometry will panaround it.

For more advanced ways to select objects, seebrush-based selection.

Flipping and rotating

DarkRadiant provides six buttons to quickly flip or rotate objects (in 90 degreeincrements) around each of the three world axes. These are available on theleft-hand vertical toolbar.

Manipulator modes

For more precise control over object motion, there are three manipulator modeswhich can be selected with buttons on the left-hand vertical toolbar.

Creating a brush

To create a simple rectangular brush, ensure that nothing is selected (ESC),then Left drag in the 2D view. A new brush will be created and sized accordingto the dragged area, with its dimensions snapped to the current grid level. Toadjust the third dimension of the brush (perpendicular to the view direction),used Ctrl + TAB to switch the 2D view axis, and Left drag outside the brushboundary to adjust the size.

Whenever you drag to create a new brush, the third dimension will match thesize of the most recently selected brush. This makes it easy to draw a seriesof brushes with the same height, such as when you need to create a series offloors or walls in succession. To match the height of an existing brush, simplyselect (Shift + Left click) and deselect it (ESC) before drawing the newbrush.

More complex brush shapes

Although each brush starts out as a six-sided cuboid, it doesn’t have to staythat way. DarkRadiant offers several options for creating multi-sided brushes inmore complex shapes. To create one of these shapes, first define a regularcuboid brush covering the volume you want the new shape to occupy, then choosethe appropriate option from the Brush menu:

While these shapes can be useful for certain architectural modelling, rememberthat brushes are always flat-shaded and are not generally a good substitute forspheres or cones created with patches or static meshes.

Creating a room

Although it is not too difficult to create a hollow room by creating floor,ceiling and wall brushes manually, this is a common enough operation thatDarkRadiant provides a couple of shortcuts. These options can be found on thevertical toolbar at the far left of the main window.

The room creation tools do not require the initial brush to be rectangular — you can quite happily Create Room with a triangular or trapezoidal brush, or abrush with sloping sides. However, with a more complex brush shape, thecomplexity of the resulting wall geometry increases considerably, so attemptingto hollow out a 7-sided sphere is probably ill-advised.

Splitting brushes

Sometimes it is necessary to divide a brush into two or more pieces, perhaps tocreate a doorway or other opening. The Clipper tool, accessed with the Xkey, is used for this purpose.

It is possible to create three split points before executing the split,which will define a split plane in three dimensions. Defining a three-pointsplit plane which is actually useful, however, may be challenging.

Reshaping brush edges

All brush edges can be moved independently, which gives you the ability toquickly create shapes like triangles or trapeziums. This functionality isaccessed via the Select Edges tool on the upper toolbar, or with the E key.

Brush-based selection

As well as using brushes to define map geometry, you can also use them to selectobjects. There are three commands on the top toolbar which convert the selectedbrush(es) into a temporary selection volume:

Creating a simple patch

A simple patch starts off as a flat rectangle, which can then be manipulatedwith vertex editing to produce a curved surface, if desired.

To create a simple patch:

Manipulating control points

With a patch selected, press V to enter (or leave) vertex editing mode. Thiswill display all of the control vertices, and allow you to select and move them.

Adding or removing control points

Control points can be added or removed from a patch using the appropriate sub-menus in the Patchmenu.

Thickening a patch

When created, every patch has zero thickness and can only be viewed from one side; however, a patchcan be made into an apparently solid object by creating additional patches automatically via theThicken command in the Patch menu.

The Thicken dialog presents several options:

Although a thickened patch appears as a solid object, it still consists of individual patcheswhich can be selected and manipulated individually. If you wish it to continue to behave as asolid, you can group the patches together.

More complex patch shapes

Just like with brushes, DarkRadiant offers several default patch shapes beyondthe flat simple patch. These can be created by choosing the corresponding optionin the Patch menu. There is no need to have a brush selected first in order tocreate these shapes, however if a brush is selected, it will be removed andused to define the size of the patch shape.

Controlling patch subdivision

Although patches are defined by Bezier curves, they are subdivided into flatpolygons for rendering. By default, the number of polygons to create isdetermined dynamically by the game engine, based on the shape of the patch.However, you can also use the Patch Inspector to explicitly set the level ofsubdivision required, which can be useful when optimising a map by reducingon-screen polygon counts.

To subdivide a patch:

The Media tab

The Media tab shows a tree view which contains all of the textures availablein the game installation. Selecting a texture in the tree will show a smallpreview swatch, along with some metadata about the texture definition.

To apply a texture to the selected brush, simply Double-click on a texturename in the tree. The tree view also offers a context menu with several options:

The Textures tab

The Textures tab provides a scrollable canvas containing preview swatches ofall the textures which are currently loaded in the current map.

When DarkRadiant first starts up no textures are loaded and this panel is empty.New textures can only be loaded via the Media tab (described in theprevious section), either by applying a texture directly to abrush, or by using the Load in Textures view command to explicitly load anentire folder of textures.

Once textures are loaded onto the Textures tab, you can apply them to aselected object by Left clicking on them. By Right clicking on a texture youcan access a context menu with a single command Seek in Media browser, whichwill highlight the clicked texture in the Media tab.

Using the Surface Inspector

Once a texture is applied via the Media or Textures tabs, you will most likelywish to adjust the alignment and scale of the texture on the brush or patchface. DarkRadiant provides the Surface Inspector for this purpose, which canbe toggled with the S key or by choosing the option in the View menu.

The Surface Inspector can be used to adjust textures on a single brush or patchface, or several selected faces/brushes/patches at once. If more than one faceis selected and these faces have different values for text boxes in the dialog,the text box will be greyed out, however it is still possible to use the buttonsto make changes which will be applied uniformly to all selected faces.

Using the shader clipboard

While constructing a map it will frequently be necessary to apply the sametexture to several different surfaces such that they appear seamless in game. Inorder to assist with this, DarkRadiant provides a shader clipboard whichallows shaders to be copied and pasted between primitives, and is independent ofthe main clipboard used for copying and pasting other objects.

Copying a shader

There are two ways to copy a shader to the shader clipboard.

1. Select a single face (not an entire brush) with Ctrl + Shift + Left clickin the 3D view, then choose Edit → Copy shader.

2. Directly Middle click the face in the 3D view (there is no need to selectit first).

In both cases, the ShaderClipboard section of the bottom status bar willupdate to show the new value of the shader clipboard. If the Media orTextures tab is visible, their contents will also update to view the selectedshader.

Selecting a texture explicitly in the Media or Textures tabs will alsoupdate the shader clipboard with the selected shader.

Light

Every map requires at least one light source in order to renderanything in game. A light occupies a rectangular volume, which can be createdand resized much like a brush, and has properties to determine its colour,visible shape and falloff pattern in three dimensions. Lights can optionallycast shadows, and can even be animated to flicker or flash.

Model (func_static)

Model entities represent geometry that is not compiledas part of the map itself. The model geometry can either be derived from brushesand patches created inside DarkRadiant, or from an external model file in ASE orLWO format. Model files are the primary mechanism for including fine detail in amap which would be cumbersome to create with brushes and patches.

Speaker

Essentially the audio equivalent of a light, a speaker entityrepresents the point from which an in-game sound source will emanate. It hasproperties to control its size and falloff, and optionally override certainproperties of the sound shader itself, such as volume.

Player start (info_player_start)

This entity tells the game engine where toplace the player when a map is first loaded. A map without such an entity willnot be playable.

Creating lights

To create a light, Right click in the 2D view and choose Create light….The position and size of the light volume depends on the current selection:

Unselected lights are shown in the 2D view as small boxes, while selected lightsalso show the boundaries of the light volume.

A selected light entity can be moved by dragging inside the small center box,and it can be resized by dragging outside the edge of the light volume. Unlikebrushes, light volumes will by default resize symmetrically, so that the centerpoint does not move during the resize.

Although light volumes can be resized like brushes, their shape can neverbe changed; every light is an axis-aligned cuboid. This does not, however, meanthat they need to look rectangular in game. See the nextsection for details on how to change the falloff texture using the lightinspector.

There are a couple of options on the top toolbar which control the display andbehaviour of light volumes:

The light inspector

When initially created, a light is pure white in colour and has an unrealisticrectangular illumination pattern matching its shape. You can change theseproperties using the light inspector, which is accessed with the L key.

The light inspector can change the properties of a single light, ormultiple selected lights simultaneously.

Light volume (omni vs projected)

The majority of lights in a map will be thedefault, omnidirectional shape. An omni light is a simple cuboid which emitslight in all directions from its center to its edges.

A projected light is pyramid-shaped, and emits light from the tip of the pyramidtowards the base. Projected lights behave more like spotlights in real-life, andcan be used to highlight particular areas or project images of windows onto thefloor.

Colour

Use the colour selector button to display a standard colour selectiondialog. As well as changing the hue, the light colour also governs the overallbrightness of the light. You can use the slider below the colour button toadjust the brightness of the selected light(s) without changing the hue, withrealtime feedback displayed in the 3D camera view if lighting preview mode isenabled.

Texture

The falloff texture controls the shape of the lit area when renderedin-game; the square texture chosen here will be mapped directly onto therectangular shape of the light volume. Light textures can be simple, such as thegeneric circular gradient of biground1, or much more complex, includingmultiple colours or animation.

Options

There are a few light-propagation options which are mostly used totweak performance. In particular, disabling shadows for any light which doesnot actually need to cast shadows can give a significant boost to renderingspeed.

Creating models

Static models can be used to provide fine details in a map which would bedifficult or impossible to create in the editor with brushes or patches. Modelsare created with an external 3D application such as Blender, Lightwave or Maya,and saved into the game asset tree in LWO or ASE format.

To insert a model, ensure that nothing is selected, then Right click in the 2Dview and choose Create model…. DarkRadiant will show the model selectordialog:

In the top-left of the model selector window is a tree of all available modelsin the game installation. Models may have different skins, which are variantsof the same model with different textures applied. If a model has skinsavailable, these will be listed as children of the model entry in the tree.

Choosing a model or one of its skins will show a preview render in the largewidget on the right-hand side. Various metadata such as the polygon count andthe applied textures are also shown in table at the lower left.

When you have chosen the desired model, click OK to insert it into the map.The model will be inserted at the position where you originally right-clicked toshow the model chooser.

Creating a player start marker

The game requires a special entity (info_player_start) to mark the position atwhich the player should enter the map. Without such an entity the map will beunplayable.

To create this entity, ensure that nothing is selected then Right click in the2D view and choose Create player start here. DarkRadiant will create theplayer start entity at the clicked position.

Since it makes no sense to have more than one player start location, DarkRadiantwill not enable the Create player start here menu option if there is alreadyan info_player_start in the map. Instead, you may choose Move player starthere to move the existing entity to the clicked position.

Creating other entity types

Entity types without a dedicated item in the right-click menu are created usingthe generic Create entity… option, which displays a dialog very similar to themodel selector:

Just like the model selector, the entity selector displays a tree of allavailable entity types in the game installation, and a large preview widgetwhich shows an approximate rendering of the entity, if appropriate. Purelyfunctional entity types such as info_location or info_player_start do nothave any visible appearance and their render preview will be blank.

Some entity types have a short textual description giving information abouttheir usage; if present, this is displayed in the text box underneath the entityclass tree.

After selecting the desired entity type in the tree, click the Add button toinsert an instance of the entity into the map at the right-clicked location. Ifthe selected entity type requires a brush selection and no brush is selected, awarning will be shown at this point.

Editing entity properties

Every entity has a list of key/value pairs known as properties or spawnargs.These properties are displayed on the Entity tab of the editing panel.

The entity panel lists all of the properties of the currently-selected entity,showing each property’s name, its current value, and an icon representing itstype (boolean, vector, text etc) if known. Selecting a property will populatethe two text boxes in the center of the widget with the property name and value,allowing the value to be edited. If the selected property is of a known type,the panel at the bottom will show a custom widget appropriate for editing theparticular property, e.g. three separate numeric spinboxes for a vectorproperty, a colour selector widget for a colour property, and so on.

The entity panel provides two options controlling its behaviour:

Converting primitives into func_static

To convert one or more existing primitives into a func_static entity, simplyselect all of the primitives, right-click in the 2D window, and choose Convertto func_static.

Manipulating individual child primitives

After converting a primitive, a number of changes are noticeable:

However, it is still possible to perform operations on a single primitive, forexample resizing a brush, by selecting it with the TAB key. Each press ofTAB will cause DarkRadiant to select a different primitive contained withinthe entity, after which it will return to selecting the entire entity. With onlya single primitive selected, all of the normal operations are possible on thatprimitive, for example deleting or resizing it.

The entity inspector widget makes it clear whether you haveselected an entity or a primitive within that entity, using the text above thelist of entity properties. If an entire entity is selected, the text will appearsimilar to Entity1, whereas with a primitive selected it will readEntity1,Primitive1.

Adding or removing primitives

Once you have created a func_static or similar entity from a number ofprimitives, you can add or remove primitives without needing to create a newentity from scratch.

Preventing leaks

A map "leak" occurs when the play area is not fully enclosed with a completeshell of opaque brushes. If the map leaks, compilation will fail and the mapwill not be playable.

In order to minimise the likelihood of a map leak, ensure that your map has allof the following properties:

Do not be tempted to avoid leaks by enclosing your entire map in asingle huge box. This may seem to solve the problem (the map will indeed notleak), but it completely negates the important performance optimisations thatthe map compiler carries out when it "flood fills" the map interior.

Locating leaks with a pointfile

No matter how hard you try to avoid leaks, occasionally they will happen. Inthis case the pointfile functionality is helpful to identify the location ofthe leak.

After the map compilation has failed with a leak, return to DarkRadiant andchoose Pointfile from the File menu. This will automatically load the pointfile associated with the current map, which contains a series of pointsidentifying the path to the leak. This path will be rendered as a bright redline in both the 2D and 3D views:

In this example we can clearly see that the map has leaked because the far wallbrush does not join up with the ceiling.