Previously referred to as the 'Doom 3 Engine', Tech 4 is id Software's current licensing platform. Powering games such as Doom 3, Quake 4 and Enemy Territory Quake Wars, Tech 4 revolutionized the use of realtime dynamic lighting as well as other technologies.

Post tutorial Report RSS ID TECH 4: Radiant - Brush Works

In this tutorial we'll see how to manipulate the brushes, and creating different structures by standard blocks. This tutorial is compatible with Doom 3, Quake 4, Prey and ET: Quake Wars. There is no need of coding/scripting or other external applications, just use the Radiant.

Posted by on - Basic Mapping/Technical - idtech 4 tutorials


[1] - Vertex Manipulating

[2] - Curve Brushes

[3] - Pipes

[4] - Simple Patch Mesh

[5] - Multiple Brushes Forge

[6] - Clip Tool

[7] - Credits

[1] - Vertex Manipulating

Create a brush on the XY View, the size doesn't matter for now. For manipulate the vertex of each side, just press V (remember to not deselect the brush). Some yellow dots now appear on the vertex of the brush, you can drag them with left-click. Remember you can change the view of the window pressing CTRL+TAB, for a better work.


Now deselect the brush pressing ESC.

[2] - Curve Brushes

After creating another brush, on the top menù, select Patch and then Bevel. A curve planar patch appear on the screen, something like that:


If you want to rotate it, with the selected brush go to Selection/Rotate and then select the axis you want the object rotate. This option is on the top menù.

Now this curve plane need thickness and we can add it going to the top menù and select: Patch/Thicken, the default value is 8, wich mean is one unit grid, leave this to default for now, and click OK. Your curve brush its done:


Deselect it by pressing ESC.

[3] - Pipes

Create an high brush, like in this picture:


Now go to Patch and select Cylinder (on the top menù). You have your pipe, you can also rotate it like you did with the curve brush above.

But naturally you would also to curve the pipe for make variotions on your map. You can do it by modifying the vertex. Press V and change the XY view to XZ by pressing CTRL+TAB.

Now its all up to you, changing the vertex you can curve the pipe at your pleasure.


Deselect it by pressing ESC.

[4] - Simple Patch Mesh

A simple patch mesh, is a planar brush where you can add a decal texture or create simple terrains. create a brush and go to top menù selecting Patch/Simple Patch Mesh. Now will appear awindow asking you the number of unit for the patch. For static decals you leave this to default, but for terrains, increase the number. For this example just leave the default number, wich should be Width: 3 Height: 3, click OK.

Now you have your planar patch where you can add the texture you want or rotate it. For modelling a terrain with it you can do as said before, changing the vertex by pressing V and dragging the yellow dots:


NOTE: The simple patch mesh is only one-side face, if your patch face is wrong and you want to reverse it, go to top menù selecting Patch/Matrix/Invert.

[5] - Multiple Brushes Forge

Sometime in your map there is some repetitive corridors or structures, but you are too lazy to build each brush everytime? No problem,you can select groups of brushes and attach them each other, for use as an unique brush.

Create some brushes, the number isn't important. Then select all the brushes you did, by pressing SHIFT+LeftClick on every of them.

Now, remember the Inspectors window on the previous tutorial? With th brushes seected press N, in the inspectors window now appear the properties of the entity. On the top you have as Entity Class, Worldspawn. Click on it and search for func_static, when you find it, select it and press ENTER. Done now you can select your group of brushes as one.


This isn't the only way to save a group of brushes, you can save them as Prefabs. For do this, select all the brushes you want to save, then go to the top menù and select: Edit/Save Selection as Prefab. Save it with the name you want, then if you want to load this prefab, everytime you need it, go to Edit/Load Prefab, and select your file.

NOTE: When you load a prefab for another map, the origin where appear willbe the same of where you saved the prefab.

You can export the brushes also as a model. Go to top menù and click Selection/Export/To OBJ

for export the brushes as an OBJ model for modify it on your 3D Application.

NOTE: The editor save also the UV coordinates on the model.

[6] - Clip Tool

This tool its used for modelling rocks or add variety on the brush, cutting the part you don't need.

Create a brush, then without deselect it, go to the top menù and select the Clipper:


Now on the XY view, you have to click two point using LeftClick. Select the first point where the clip start and then the second where the clip should finish, and you will see the part cutted. When you cut a part, press always ENTER, if you press ESC the brush return to normal.

Change also the XY view to XZ for cutting different part:


[7] - Credits

Author: Nicola "Neurological" Capecci




Simple, easy to understand and should help those just starting out.. nice work...

Reply Good karma Bad karma+2 votes

Thanks a lot, your tuts are really helpin me out, yep Im a noob here in iD4 tech.

Reply Good karma Bad karma+2 votes

Nice tutorials. Well written, clear and simple. Nice work,


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