Here is my theory.
The Orbs are NOT <----NOT base markers. The base markers are the little pillars that have either the red lights or the blue lights. THE ORBS ARE NOT BASE MARKERS YOU PILE OF CRAP!!! haha...just joking. Anyways, what I believe these 'Glowing Orbs' are are terrain and nature filters...allow me to explain.
"Sandbox combines large-scale vehicular combat with a limitless amount of Forge customization. Boasting a tiered, open-world layout, Halo 3 players will be able to build their own unique game experiences using the Forge map editor. Sandbox is a map unlike any Bungie has ever created."
-From Bungie Weekly Update: 1/30/09
MY THEORIES
Main Points
○ large-scale vehicular combat
○ limitless amount of forge customization
○ open-world layout
○ build their own unique game experiences
○ a map unlike any Bungie has ever created
Explanation
Obviously, those three sentences are incredibly powerful and store lots of information. It is I who have brought the information out.
The Theory
My theory that ties in what you have seen previously in the bulleted list all together. The map is pretty much what we all have been waiting for: A Large-Scale Foundry Map Editor. I believe that those little 'glowing orbs' are really terrain and nature filters. I mean, why can't it be because Microsoft even said that it is unlike anything that Bungie has ever created. I think that the blue orbs are for the terrain you choose and the red/orange graphed orb is for the nature effects. I believe that when you go into forge, it is really a blank graphed canvas that you saw in those videos a long time ago...I cannot remember their names but you know what I'm talking about. Well, you first get to choose what type of terrain you want the map to be built off of such as:
○ Sand
○ Grass
○ Dirt
○ Water
○ Snow
○ Floating
You then can pick the land formations you want such as:
○ Flat
○ Hill 1
○ Hill 2
○ Hill 3
○ Hill 4
○ Hill [etc]
○ Canyon
○ Stream
○ Cliff
and place them on the maps just like you would a crate or a traffic cone. Once that is configured, you can add buildings or 'flat plates' that you saw on the bottom of Sandbox.
○ Class UNSC (foundry)
○ Class Covenant (snowbound)
○ Class Forerunner (avalanche)
○ Class Brute (sandbox)
○ Class Flood (isolation)
○ Class Nature (trees, bushes, rocks, etc.)
In each of these categories, there would be relative objects such as for example:
Class UNSC
○ Crate
○ Ramp
○ Etc.
Class Flood
○ Infected Tree
○ Flood Infection Form Sack
You get the point. Anyways, after you assemble all that together, you can add Nature Effects such as:
○ Sunset (sandbox)
○ Sunrise (sandbox)
○ Moon (night)
○ Sun (day)
○ Snow
○ Rain
○ Wind
Either way, you understand.
-mut***********688
EDIT: I must have lost my train of thought because I forgot to add something about the Guardians. Depending on which map you are on, you will choose like boundaries and ways for the Guardians to kill you...such as the Sandtrap tripmines, or even a Rocket coming from outer space and blowing you to hell.