I’m laying out quite a few recessed 6" / 4" lights for a home and was curious if there are any tools or extensions that would help me with lighting placement versus having to do all of the math myself.
Fortunately, the rooms are very rectangular so not a ton of complex layouts.
What kind of math have you been doing for that?
Generally using the Move tool to create arrays works well enough for me.
I think the answer depends on what sort of layout you need. A linear or rectangular array can be done using the array copy function of the move tool, as @DaveR noted. Other arrangements would need other methods, but likely ad hoc to the specific case.
What I was hoping was to find a tool that could help me identify the intended perimeter and then calculate a symmetrical array that would offset from the walls. I’d have to imagine an awful lot of designers and architects would need to perform this function.
one thing that i find useful is the IES viewer (http://photometricviewer.com/) which lets you model the lighting based on the model of the unit and bulbs - many vendors have IES files you can use.
then as far as layout - depends.
if you’re running soffits versus flat ceiling, under cabinet, over cabinet, and then lighting - general, spot, artwork, effects, etc. also controller - individual? color changing? grouping? etc
i’m wagering many architects reach out to a lighting designer to help solve it if its more than simply linear layouts. e.g center-line on the bottom of the space to provide a general lumens/watts level per area, same for flat ceiling - and sometimes extra lighting for occupancy locations in the rooms etc.
Click in sequence on the scenes tabs of this SU file for ideas.
Resess lighthing aroud a ceiling.skp (271.8 KB)
First off @jean_lemire_1 you are a true gentleman 
I sincerely appreciate you taking the time to send that over to me. I don’t know why using an offset wasn’t my first thought!
Second, what’s the method I use to create an array like you did? I know that I can copy/paste and then set a multiplication “x3” however how do I determine a perfectly distanced array to the opposite corner of a box?
Having just done a recessed lighting layout for a home, it seems to me there are too many variables relating to the nature of the space, the specs of the fixtures, the desired lumens psf in any given area, furniture/fixtures/window layout, etc. There are SU tools to help with the layout and spacing, but most homes require special attention to the lighting needs of each room, so I don’t see how SU can figure all that out for you. Maybe I misunderstand what you’re looking for…
Copy the object to its final destination then enter /X followed by a press of the Return key where X is the number of intervals that you want. You shall see your typing in the Dimension Window.
For example, to get 5 instances, select the first one then copy it to the final distance then type /4. This will give you 4 copies equally spaced from the original, thus, 5 instances (with 4 intervals) in total.
Open the Instructor Window (Menu Window → Instructor. Read all the text then click on the link at the very bottom of this text to go to the help system. This shall open a whole lot of informations in the form of more text and videos.
When done with the instructor, simply close its window.