Brush Tools Face

The Face tool lets you apply and adjust materials on built geometry. Because you interact with the built geometry in this mode, brushes are hidden.

Selecting and Deselecting

Instead of selecting brushes, in Face mode you primarily select each face independently from its brush. To select multiple faces, hold Shift and click. To remove a face from the selection, hold Ctrl and click.

The green face is selected

In addition to being able to select faces by clicking, you can also select all the faces of a brush or brushes by selecting the brushes from the hierarchy. SabreCSG will automatically select the faces from the brush.

There is also a selection tab on the Face UI which has a number of helpers:

• All – Selects all built faces
• None – Resets selection so no faces are selected
• Invert – Inverts the selection
• Excluded – Select all faces that are marked as exclude
• Same Material – Selects all faces that share a material with any of the already selected faces

Adjacent:

• Walls – Select all faces that share a vertical edge with any of the selected faces.
• Floors – Select all faces that share a horizontal edge with any of the selected faces and have a normal that points up
• Ceilings – Select all faces that share a horizontal edge with any of the selected faces and have a normal that points down
• All – Select all faces that share any edge with any of the selected faces

Clicking one of the adjacency helpers repeatedly will expand the selection, see this animation:

Expanding the selection by repeated adjacency clicks

Applying Materials

Once you have at least one face selected, you can apply a material by dragging one from the Assets window to the “Mat” field below the SabreCSG tool selection bar. Alternatively, you can click the circle button next to the “Mat” field and pick a material from the window that appears. As mentioned above, these approaches require multiple precise mouse clicks, so if you are going to apply a material on many faces, it is fastest to apply materials to groups of selected faces.

Often, it is useful to have placeholder materials that distinguish walls from floors and ceilings. SabreCSG comes with a folder called Example Materials, which you can find in the Project window inside Assets/SabreCSG. When working on a large, unlit level, it can be easy to mistake one kind of surface for another; having placeholder materials helps prototype spaces and gives an indication of scale.

Materials and UVs also persist in other brush editing modes. If you apply a material to a brush’s built geometry, duplicate the brush, and then rebuild, then both brushes will have the same materials and UVs. The default brush has the same material on the sides, top, and bottom, so if you apply a different material to the sides with this first brush, and then use it to create the rest of your level geometry, it can save time with placeholder materials. This persistence is also useful with complicated detail geometry, such as the trim of an arch. By aligning the materials once, you can then duplicate the brushes without needing to align the materials again.

If lightmaps were enabled during the build process, then applying materials to the faces of built geometry can sometimes cause errors. Because of this, it is best to treat texturing and lighting as separate passes when building a level.

Translating UVs

Once you have selected a face, a white dot will appear. This reflects the mouse position when you click and drag the face. Like moving brushes, the UVs of a face snap to the grid. To increase or decrease the grid size, go to the SabreCSG settings. You can also use the keyboard shortcuts “,” and “.” to decrease and increase the grid size.

Translating UVs

Rotating UVs

To rotate a selected face’s UVs, hold Ctrl and then click and drag. This will snap based on the angular snapping, which you can change in the SabreCSG settings. If you want more precision when you rotate, there is also an option below the SabreCSG tool selection bar, left of the Rotate button. Here, you can specify the amount of rotation in degrees, positive or negative, and then perform it by clicking Rotate. This more precise method is useful for recurring angles. For example, the trim of a staircase should have a rise to run ratio of 1 to 2, which is 26.565 degrees. Trying to snap to this angle would be impossible, and trying to rotate with snapping disabled would be inaccurate, so it is best to use precise rotation.

Rotation in SabreCSG occurs around the center of the face, so if you need to perform a precise rotation and translation, it is best to rotate first.

Rotating UVs

Scale UVs

Beneath the SabreCSG tool selection bar, there are also options for flipping, and scaling UVs. The Flip buttons will mirror the material across the X or Y axis, or both. To scale, there is a field next to the Scale button where you can enter a precise value, or you can quickly scale by using the “x 2” or “/ 2” buttons.

Generally, it is best practice for a material to be roughly the same scale throughout a level. Seeing a a material on a distant wall that is much larger than the same material nearby can harm the sense of depth in a scene and can disorient players. Because of this, it is usually best to uniformly scale the material itself in the Assets, instead of scaling face UVs independently. However, when working with angled geometry, you may need to stretch or shrink a face’s UVs slightly. The best way to do this is to enter a number near 1 in the field next to the Scale button. Numbers greater than 1 will make the material appear smaller, and numbers less than 1 will make the material appear larger. You can repeatedly apply the scale adjustment to a face. For small adjustments, use values near 1, like 1.05 and 0.95.

Auto UV

There is also a button called Auto UV. This recalculates the UVs of selected faces based on the world position of their vertices and is a great way of resetting UVs if they get distorted or you want to redo them.

Auto UV

Auto Fit

There is also an option to scale the UVs to fit the selected face. This is particularly useful if you need a texture to exactly span a face (such as a vent or something decorative like a painting.)

Auto Fit

Follow Face

When geometry is curved the Auto UV option won't generate satisfying results. First select a face. Hold Control+Shift+Left Mouse Button and move over the neighbor faces to align them perfectly.

Follow Face

Extrude Brush

Sometimes it’s also useful to be able to rapidly create a brush from an existing face. By selecting a face or faces and clicking the Extrude Brush button, SabreCSG will generate new brushes that are extruded 1 unit from the face.

Extrude Brush