This tutorial is intended to provide a quick light rig, with quick render time, and good results. I don’t claim to be a master of lighting in Blender though. Hope you find it useful.
Start a new scene in blender and switch to top view, select add mesh, circle, set the circle to have anywhere from 8 vertices to 12 vertices , ( choose the number based on how powerful your computer is) I like to use 12. Dont fill the circle, then go into edit mode.
This is what you should have :
Now press E key to extrude, select only edges then press S key to scale the extruded vertices down towards the center, now activate proportional editing by hitting the O key, now hit r key and rotate the vertices so they are offset from the outer ring of vertices as in this image :
Now exit proportional editing mode by pressing the O key. With the inner ring of vertices still selected press e key, select only edges then hit s key to scale the new vertices down to the center, finally hit alt + m key to merge the vertices in the center.
You shoud have this :
Ok now for a few tips, as you see in the picture (3) the outer 2 loops of vertices are kind of farther away from the center, this isnt how you really want them to be. Eventually each of the vertices is going to become a spot light, and the offsets between each vertice are designed to minimise artifacts that could develope in the shadows of the final light, I have left mine like this so that you can see what I mean in the final renders. The trick to getting the best out of this rig is to have a good balence in the distances between the vertices in the two outer loops and the center, so select each of the outer vertice rings one at a time and scale them down a little more towards the center. Next leave edit mode then hit F7, now in the tab labeled “Draw” locate and activate the axis button. This will make it easier to find your “light holder” later. since when ever you wish to move or rotate your light you will need to select the holder part only. ok with your light holder object still selected hit control S and select cursor to selection to snap the cursor to the exact center of the light holder, when that is done hit add, lamp, spot. Then go to the lamp settings and enter the following settings, dont worry about the clip start or clip end as you will need to do that when you actually have a scene to use it in (make sure the clip end setting extends just past your models when you do).:
Ok now with your spot still selected hit and hold shift and select the light holder you made before, then hit control + p to make the light holder the parent of the spot. Next deselect everything, then select only the light holder then hit F7 to switch to the object tab, locate the anim settings tab and activate the dupliverts button, Like here:
Now this is what you should see: from the side view :
Ok thats it, just keep in mind in order to move or adjust rotate etc your light you need to grab the light holder, in order to change the settings of the lights you just change the settings on the one in the center. Keep in mind if you scale the light holder up it will effect the shadows of your light, and usually not in a good way. Also I only used the most basic settings for the lights so as to ensure a fast render time, you can easily tweak them to improve results, right away your going to need to shorted the clip end distance because as you can see in the last picture it extends way past the end of the light cone, in reality it should only just extend just past what ever object your rendering.
Here are the results, however keep in mind that I said I left the outer 2 vertex rings out a bit too far to show you how that can mess up the shadows, this can be scene in the following pictures, but as long as you keep the loops of vertices close to one another you shouldnt suffer from this problem.
Now Here is how the shadows will look when you have the vertices closer together like they should be:
Now if you change the size of the light holder ( the original circle) and scale it up, the shadows will get more diffuse, if you scale it down the shadows will get less diffuse. Of course you can only scale it up or down so much before you will begin to see the banding.
There are a lot of different types of lights you can make this way, instead of just using one light you can use more, I tend to use 5 with one in the center, and the outer four slightly angled away from the center light (space these very close together), though on older machines it could make for slow render times.
The original spot was basically set to a spots default settings, so increasing the number of shadow buffers or increasing the softness value could improve your results even further , however this will increase render times.