I wanted to improve on the classic nerf “mobstacle” design from Nerfhaven which used PVC and tarps to create inexpensive, lightweight cover for use in tagging-sport (nerf, airsoft, paintball, etc) field design. I also wanted to create a capture the flag experience more interesting than just grabbing a flag off the ground or a ball or whatever.* So here it is. 

Mobstacle:

Designed using ½" Sch. 40 PVC. Some people use ¾"; I didn't draw this for ¾ but it can probably be scaled by 1.25 and work for ¾" PVC too. I spent quite a bit of time thinking on the dimensions and while you can use anything you want, I settled on a 41" high by 36" wide frame. This makes it so cutting (4) 10' PVC sticks, two each of 36", 36", 41" and 41", 41", 36" yeilds (3) frames. You'll also want 4 corner pieces per frame - those can be purchased (or printed, but I don't think it's cheaper) elbows and T's. I used two elbows and two T's for my frames, using the leftovers from the frame cuts to optionally join two frames together to make a taller one. You could also use the T-ends to assist with anchoring by staking the frames to the ground.

If you're doing what I did, you'll want to print (6) clips and (6) clip_cover's per three-frame obstacle. Four clips join the three frames together, two are put on the ends to store the frame collapsed.

For the cover, any fabric should work, I found an inexpensive plastic drop cloth and used that. The cover_clips may not hold heavier duty fabrics, for those sewn pockets, duct tape, zip ties, etc. would work.

Flag:

I ended up making my tripod use 18" legs, which would mean one stick for a tripod and a 5'-6" flag. That seemed short so I used a longer piece for my flag. 12-18" legs seem to be OK for 4-7' flags, shorter would work better if also weighted or staked down. Put the flag pole topper on top and optionally use the cover_clips to attach whatever you want to use as a flag.

*Note for Capture the Flag: For nerf, I do not find classic CTF to be a good gametype - it's too easy to drop your blaster, run for the flag, and run away before anyone can tag you; even with high powered blasters. I intend to use mine for various other gamemodes:

• King of the Hill: Markers for where/what the hill is.
• Various versions of Soccer, but with flags: put the flag in the middle of the field and to score you have to run it to the other team's starting line.
• Control points: if your team's flag is in the stand, you control the point.
• Team starting locations.