From CustomCoD Wiki
If you notice that you seem to be missing buttons as you scroll down then your Radiant window isn't wide enough. You must enlarge your window horizontally to see the rest of the buttons. If for some reason you can't then the important buttons have keyboard shortcuts and can be found in the menus.
-Open- Opens a previously saved map file.
-Save- Saves your current map.
-Flip XYZ- Flips your selection around the center pivot in the respective direction.
-Rotate XYZ- Rotates your selection around the center pivot 90 degrees clockwise.
-Complete Tall- Anything inside your brush in the 2D view will be selected.
-Select Touching- Anything touching your brush will be selected.
-Select Partial Tall- Same as Complete Tall but they only touch the brush.
-Select Inside- Selects anything inside your brush.
-Clipper- Select a brush then toggle this.
2 dots will cut the brush along the connected line.
Add a 3rd dot and it will cut from line 1-2 to 3.
Shift + Enter will save both parts, Enter will keep what is previewed.
CSG tools have a history of errors in maps and have corrupted some. Some never have problems, use at your own risk.
-CSG Subtract- Removes everything inside your selected brush.
-CSG Hollow- Hollows your brush, thickness is your current grid size.
-Texture Flip XY- Flips the texture relative to the selected axis.
-Texture Rotate- Rotates your texture 90 degrees clockwise.
-Cycle Layer- Changes the view to Color, Light map, and Smoothing.
Color shows your textures (Default)
Light map shows you shadow resolution.
Smoothing shows you how the game will render a surface.
Hard – Crisp edges.
Smooth – Rounded edges.
-Camera Mode- Classic COD style, GTK Radiant Style, Doom III style.
-Cubic Clipping- Stops your 3D view from drawing past a certain distance, this can be set in Preferences.
-XYZ- Changes your grid view, top, side, front.
-Free Rotate- Click to rotate your brush in your 2D window, smaller grid has more options.
-Free Scale- Click to scale your brush in your 2D window, smaller grid has more options.
-Lock XYZ- Stops a selection from being moved along the selected Axis.
-X Curve- -Can't select and mesh, terrain or curved.
-Show patches as wireframes- All meshes are rendered as a wireframe.
-Redisperse Patch Points- Toggles the addition or subtraction of verts in a mesh.
-Lock and Unlock Vert points- Toggle each one and select your verts.
-Cycle edge direction- Toggle and click on your terrain meshes, this will rotate edges to help when meshes are bent.
-Show entities as- Choose from wireframes to fully skinned, entities are most commonly models.
-Toggle Alpha Rendering- On or Off, alpha renderings is see through textures like glass.
-Disable selection of...- These give you the option of making certain items in your map unselectable so you don't accidentally modify them.
-Down Arrow- Drops selected models to the floor and applys a random rotation and scale, useful for foliage.
-Down Arrow on slope- Drops selected model to the floor.
-Zero- Drops selected models to the 0 height.
-Two boxes, arrows to floor- Uses previous 3 buttons as options. Drops to floor.
-Two boxes, arrows uneven- Uses previous 3 buttons as options. Drops but keeps relative height.
-Tolerant Weld- Shows a line where verts will be connected because they are within the TW distance setting in preferences.
-Stamp- Changes the prefab in your map so you can edit individual parts.
-F- Texture search.
-Triangle- Converts a brush into a mesh triangle.