Before we start, let me underline that this is by no means a straightforward process. You should start only if you are ready to edit programming-language-like text files and download, unzip and manually organize files. It needs several hours, some debugging and tweaking, and possibly more hours to compute the final image.
Ok, if you have read so far, then you are at least curious to know what it takes. What follows is based on Koyan's excellent tutorial with some tweaks. Let's see how a typical render is made!
Step 1: I install LDraw. LDraw is an community-maintained database of LEGO bricks that will be needed for our photorealistic renders. As you can guess, this is needed once only. I download and unzip several files:
- LDraw official parts (Core Files and Libraries / LDraw Parts Library, zip format). I unzip them in a directory on my computer. This is my LDraw directory.
- Many bricks are not in the official release. I download the LDraw unofficial parts as well. Unzip those files as well and move them in the LDraw directory too. Some files will already exist, I don't overwrite them.
- LGEO is another parts library that is made especially for POV-Ray renders. It contains fewer parts but those are nicely modeled. I download and unzip it into a separate directory.

| The original dome in Lego Digital Designer |