as for volumetric light you need to use trapcode lux or use expressions to link the 2d shine to a 3d light.
You can fake volumetric light with a masked and blurred solid set to add or screen, with the beam effect blurred, with Trapcode Lux (simulates real light volumetric light from AE lights) or by masking and bluring an adjustment layer with color controls. Give us a screenshot and somebody will probably give you a solution.
As for constructing your Icosahedron the Wkipedia page gave you the solution. It's just a matter of laying out solids that are the right shape, adjusting the anchor point and then rotating and parenting. There's even a perfect layout template. Just download it and then create some solids that are masked and stacked to fit this shape exactly. Set the anchor points to matching edges, rotate, parent, rotate, parent, rotate, parent until your Icosahedron is complete.
There is also a vector graphic on the wikipedia page.
You can fake volumetric lights with all sorts of conventional tricks like stacking multiple circles to create nicely fading point lights or in your case using a radial wipe and effects like CC Radial Fast Blur and similar to create light cones. As Rick suggested, an Icosahedron is just a bunch of equilateral triangles that are all connected. Should be easy to put together...
hey rick thanks for your response, i got the volumetric light down. im not so sure i understand the icosahedron part, is that image you attached the template i should follow to construct the platonic solid?