Step 7 – Postproduction rendering
You are almost done. Remember that you enabled two additional channels—depth and alpha—for the final rendering. These special render channels will allow you to do all sorts of postprocessing wizardry in GIMP, which is the subject of the next chapter.
Depth render
The first image that we will save is a depth render. It represents the z-information of the image, that is, the distance of a point to the camera.
Switch back to the Channels tab.
Under Currently visible, set the Channel option to Depth, as shown in the following screenshot:
Adjust the Max Z (m) option until you can just about see the farthest corner of the atrium. For my viewpoint, this is at 65 meters.
Save the image as a PNG file.
Alpha (mask) render
A mask render is a black-and-white representation of all the outlines of objects in the scene. The render will show whatever is present in the scene as white and the rest as black. This is especially useful when you need to replace the background of a scene...
