Retroreflective Chromakey Experiment

I played with some green screen chromakey stuff for video last year.  It’s a bit fiddly to get the screen and the subject lit right for it to work well.

I was excited to learn that it was possible to get better results with a retroreflective screen and a colored light ring.  The general idea is that the fabric reflects the light back in the same direction from which it came.  By shining even a relatively dim colored light at the screen from right around the camera lens, you get an almost perfectly-even colored background.  It is much less sensitive to the subject’s distance from the screen, etc.

John Park posted a project write-up with his plan for building an appropriate light ring a few months ago.  It looked pretty straight-forward.  So, I gave it a go.  My 3D printer is not large enough to print his mount design in one piece and, I didn’t really want to mess with printing in sections for assembly.  Instead, I did a quick (and pretty sloppy) adaptation of the design in lasercut acrylic.  The LED ring sits in a channel made with a bunch of little L brackets, glued on with acrylic solvent.  Similarly, the grippers are several layers of acrylic glued together.

The electronics design and code are all straight from John Park’s project.

This works really well! Light spill on the background from lighting the subject can still be a problem.  I was able to adjust settings for the chroma and luma range in post to compensate where I had issues pretty easily, though.  In later attempts, I was more careful about where I pointed my lights.

It is not clear from the photos but, it is better to get the screen as flat as possible.  It works with a little wrinkling but, it makes the light spill issue more likely.  I tightened the screen to the frame a bit more for later attempts.

It is also worth noting that the retroreflective fabric bruises pretty easily after its protective film comes off.

Adding Dimension to Laser-Cut Acrylic Earrings

Translucent Orange Dished Acrylic Spiral Earrings

I am seeing a lot of interesting laser-cut acrylic earrings in the forums and on social media right now.  There is a range of interesting and intricate designs.  They are, however, all quite flat.  I wasn’t sure if people just hadn’t thought of heat-shaping them or, if there was some extra challenge in doing so.  I have done some heat-shaping on other acrylic projects (like the VR Headset Wall Mount and the Paper Towel Roll Holder) and, thought I would give some simple heat dishing a go.

Long ago, my grandfather showed me how he was doing silver piercedwork jewelry and, I later did something similar with hand-cut paper earrings I was making.  A wooden dishing or dapping block is great for this sort of thing.

If you are curious or, want to give it a try, I made a quick (3 minute) video showing how I produced these dished/domed acrylic spiral earrings and skull earrings (it is October, after all).

TL;DW (too long; didn’t watch): heat gun on low, moving constantly with the center over the outer edge (to avoid overheating the center), about an inch away, for 30-40 seconds. When the acrylic starts to droop, apply pressure to hold in the desired shape. Then, allow to cool for about 40-60 seconds to re-solidify.

Acrylic Wall Mount for Oculus Quest

Acrylic Wall Mount for Oculus Quest

I recently got an Oculus Quest VR headset to help encourage me to do some more cardio activity through the long Phoenix summer. Looking at it sitting on the floor for a couple days made me realize it really needed a better place to be when not in use. It needed to be near enough to a power outlet to charge and, convenient enough to just grab it and use. I keep it in a room where I exercise and practice my taiko. So, there is not a lot of furniture. A wall mount seemed like a good choice.

Nothing I found online really looked like what I wanted, though. I have some 1/4” acrylic that is tinted with green in a way that gives a solid impression of glass. So, I thought I would try making a wall mount from that.

You can see the result in the photos here and, in the video.

If you want to make one of these, the files are all linked below.

Instructions / Fabrication Notes

The red-brown and purple outlines are the main cuts. I just used the standard Thick Acrylic Proofgrade settings on the Glowforge for those. I separated them out of habit for preferring to cut from the inside out.

The pale green rectangles are for position of the Command Strips, if you want to use those. You probably don’t want to cut or score them.

If you want to use screws to mount it instead, the gray circles would be engraved to an appropriate depth for the heads of the screws with the inner red circles cut through. These were set up for #6 screws. I didn’t go this route. So, you are on your own for the appropriate engrave settings. Ideally, you would run tests on a scrap.  If you are not using screws, set these to ignore.

I cut the forms from Medium Draftboard. Any inexpensive 1/8” thick wood-based stock should work fine.  Cut two sets from the file below.  If you have a better idea for how to do this, let me know in the comments below or, send me a message.

The easiest way to understand making the bends is to watch the video. Basically, you want to localize the heat to where you want each bend as much as possible and, brace adjacent areas you don’t want bent or deformed to keep them from bending. Bending the main necks of the controller hooks before turning up the ends of the prongs is probably best. It is likely also easier to bend the controller hooks without the central hook being in the way of setting it down flat.

Design Files

These files are for personal, non-commercial use only. If you want to produce these to sell or for other business use, please contact me to arrange for licensing terms.  Also note that, by referencing these, you are agreeing to release any variations you create under identical terms.

Attribution-Creative Commons NonCommercial-ShareAlike

Quest Wall Mount SVG

Quest Wall Mount Heat Bending Forms SVG

Resources

I know not everyone has a laser cutter but, many communities have maker spaces where you can get access to tools like laser cutters and, assistance learning to use them for free or, for a small fee or donation. Support your local communities, learn new skills and make new friends!

Find a maker space near you.

Of course, if you really want your own laser, feel free to use my Glowforge referral code to purchase your own. Glowforge will give you a discount off their posted price and, I will get a credit kickback to help defray the cost of materials for future projects. Your support is always appreciated.

Amazon referral links for the heat gun and shop incidentals defray IT and hosting costs for a local arts organization (Arizona Aikido):

Mini Heat Gun

Utility clips

Glass Green Acrylic

Command Picture Hanging Strips

Glowforge laser cutter