Diffusion Panels

They are awesome!  They rule the kingdom of DIY Light Modifiers through their old servant Bang for the Buck.  Which still goes strong in my domain.

They can soften the sun or bare flash.  They can be used as a reflection panel for something like this or just put on the ground for this nice cookie-cutter solution (fast forward to about 50% for behind the scene details).  It works so well, after trying one I built another.  Both are a little more than 4'x7' and are made of 3/4" schedule 40 PVC pipe and rip-stop nylon.  Here is the necessary attribution to Dean Collins' tinker tubes with some BTS videos of this great guy.  Building process is well documented.
Look at this one flash head-shot - compare results of use of a 43" diffusion umbrella to that of a 4'x7' diffusion panel.  The light diffused by a large panel is soft and enveloping.
The (only) bad news is that a more powerful light source (or sources!) are desired.  Need to check my Amazon rewards balance!
What works:

• Large (4'x7') diffusion panel made from PVC pipes and rip-stop nylon offers good quality (both diffused and reflected) light for about $25 in materials.  It is still relatively portable - can be packed in seconds into a 4'x8" cylinder.
• Ball bungee cords work great to keep the disassembled frame pieces together.  They can also be used to attach one such frame to another.

What does not work:

• I am starting to run into limitations of 2x SB-600 flashes.  For a high key setup I need at least 3, better 4.   But this has (almost) nothing to do with the subject.