Fig 1. Marking Menu

Fig 1 shows you what you get once you have hit the <G> key; a handy reference to the various operations towards the bottom of the window.

<LMB> - Marking Inside Box 

Fig 2. Marking Inside a Box

You can draw out a box by holding down the <LMB> while dragging the mouse; let go of the mouse button and all faces inside the drawn box will be marked (see Fig 2). This includes faces that might be on the other side of the object, obscured behind the faces at the front. Hidden faces will not be marked.

<RMB> - Unmarking Inside Box 

Fig 3. Unmarking Inside a Box

Draw out a box using the <RMB> and all faces inside the box will be unmarked (see Fig 3).

<G> - Painting 

You can use the mouse pointer to mark faces in a more interactive way using the painting method. By typing <G> a second time you'll paint a single dot under the mouse pointer. Unlike the box selection method, only the faces you can see are marked; the painting doesn't go all the way through the object.

Fig 4. Painting

If you want to paint more than one dot, just hold down the <G> key and faces will be marked wherever you move the mouse pointer (see Fig 4). When you want to stop painting, let go of the <G> key.

If you want to unmark using the painting method, use <Shift-G> instead.

<F> - Filling 

Fig 5. Filling

To mark an area of unmarked faces in a flood fill fashion, move the mouse pointer into some part of that area (see left side Fig 5) and type <G><F>. The flood fill will not cross a boundary of already marked or hidden faces (see right side Fig 5).

In Fig 5 the smile of the face has been extended to fully encircle the ankle, before filling, otherwise the whole leg would have been marked.

You can unmark using the flood fill method by just pointing the mouse pointer at an area of marked faces before filling.

If you want to stop the flood fill, hold the <Space> key.

<=>/<-> - Grow and Shrink 

Use <G><=> to grow or <G><-> to shrink the current marked area by one row of faces. The marking menu will remain active after the change, so you can use <=> or <-> again to further expand or shrink the marked area.

<S> - Swapping 

Fig 6. After Swapping

To swap the marked and unmarked status of all visible faces, type <G><S> (see Fig 6).

<U> - Unmarking 

To unmark all visible faces, type <G><U>.

<Home> - Focus 

To focus the camera on all visible marked faces, type <G><Home>.

[edit] Additional Tools

Fig 7. Additional Tools

Largest 

The largest contiguous piece of mesh is marked, and the camera focuses in on this area.

Next 

The second largest contiguous piece of mesh is marked, and again, the camera focuses in on these marked faces. This can be used in conjunction with <B> key bridging to join the largest pieces of "floating" mesh to the main mesh.

Facing 

All visible faces that are facing the camera are marked. The number value is the threshold angle, and setting it to 180 for example will mean that all the faces you can see are marked.

Paint Thru 

Normally when painting faces with the <G> key, only the foremost faces under the mouse pointer are marked. By ticking this option, all faces under the mouse pointer are marked, even those you cant see on the back side of the mesh.