Re-arranging to hex grid. Drawing a few hexagons helps with manipulation.
Scale circles. Move to fit+/-.
ScaleIndividual Script to shrink the circles back to size.
CenterPoint script is helpful.
Better, but not done.
Could repeat...
- Brian
Edit, Deleted atachment.
Google search of "Locomotive steam boiler", images, show hex "D" layout.

Hi Brian and Michael,

Thanks for the input and advice I am modelling a flange for a heat exchange unit and came up with this as a manual solution.
A series of semi circle arcs which I used unwrap curve. Worked out the length of each curve and used array over curve once I knew how many per curve. Gave a good enough result not perfect but should disperse heat even enough. Will explore Circle Packing in Rhino but was on tight time frame on this one so sometimes time spent learning new tricks versus getting the knuckles dirty and knocking it out.

Hi Alex.
Your solution looks excellent.
Maybe a fibonanacci layout would work?

-Brian

Scatter tools, dispersion ...? by Max Smirnov
http://moi3d.com/forum/index.php?webtag=MOI&msg=6486.1

Hi Alex,
I have created a basic spacing nod file on the Nodeeditor that can set minimum gaps.
The dimensions that can be adjusted are shown on the photo.
The number of arcs are 12 but if you need more let me know.
Anyway hope this helps.
Barry

Edit:
Nodeeditor added.

Hi Barry,
Many thanks for taking time in putting this together looks great - I have a large collection of your scripts and your input is gold.
I am having trouble running the node am I missing some components?
Alex.

Hi Alex,
I have updated my previous post adding the Nodeeditor I used plus a modification
to the nod file collating the outputs into one so you can see the total number of circles.
Cheers
Barry

Hi Barry,

Thanks again for your input looks great and working for me now - Will add to my collection of BARRY SCRIPTS your insight is well appreciated - my NODE skills are basic and looking at your MACRO section makes my head spin :) your contributions to the MOI community highlight how such an agile tool can be used to solve high end problems.

Keep powering on
Alex.