Introduction: Plastic Pail 3D Scanner for 123D Catch
Build your own 3D scanner on the cheap! All you need is less than $50 of hardware store materials, a digital camera, and 123D Catch.
Why a plastic pail? 123D Catch works best using pictures taken at even intervals around an object under good lighting conditions. Using a white, translucent pail gives you an easy way to create a diffuse light source and move a camera at even intervals around and object.
Step 1: What You'll Need...
1. Translucent pail and lid.
2. Digital Camera
3. Light source you can position over the pail.
4. Painter's tape or masking tape
5. 4 Wood screws, #6 x 1/2"
6. White spray paint
7. Permanent Marker
8. 12" x 12" x 1/2" Piece of plywood
9. Velcro with adhesive backing, 3ft
These are all things I was able to find at my local Home Depot. Here are some important tips:
The Pail: The camera will be positioned just outside the pail. The pail needs to be wide enough so that the camera is not too close to the object you want to scan. If the camera is too close, it won't be able to focus on the object. For my camera, I was able to use a 6.5" wide pail.
The Plywood: This is to have something you can screw the lid down to. A work bench or anything thick enough for the screw will do. I'll be screwing the lid down to my old second-hand desk.
Step 2: Prepare the Pail
Start by cutting a vertical slit in the wall of the pail. The slit should be wide enough for the camera to look through without seeing the outside of the pail. If it's too wide, the lighting conditions won't be so great. For my setup, a 1" wide slit did the trick.
Next make a mark with the marker as shown. Later you'll use this mark to help take evenly spaced pictures.
Before spray painting the inside of the pail, you'll want to protect the bottom from paint. This will allow diffuse light to enter from a direction that won't blind your camera. Cover the bottom with painter's tape to protect it. I also used a wooden ring I had lying around, but just painter's tape should do.
Now you're ready to spray paint the inside. Ideally, you'll want to use enough coats so that very little light enters through the walls. Try to limit how much paint you apply with each coat to prevent the paint from running. 123D Catch will work better if the paint is evenly applied. Once dry, remove the painter's tape. Going forward, you'll want to avoid bending the pail too much so that the paint doesn't crack and peel off like mine did.
Finally, apply strips of the soft velcro to either side of the slit.
Step 3: Prepare the Lid
Prepping the lid is a snap compared to the pail. Start by making 30-40 evenly spaced marks around the lid with the marker. For my lid, I used a distance of 3/4" between marks to make 30 marks. If you're using a different size lid, just remember: Perimeter = pi x diameter
Now screw the lid down to the plywood with the screws. This will keep the lid in place and flat during the picture-taking process.
Step 4: Prepare the Camera
Here's where you'll use the scratchy side of the velcro. Attach 2 small strips to the camera as shown. The distance between these strips should more or less match the distance between the soft velcro strips on the pail.
Next use 2 more strips to make 2 rolls, each with ~1/2" diameter.
Step 5: Position Object, Pail, and Lamp
Place the object you want to scan in the center of the lid. Next, snap the pail into the lid and position the lamp over the pail. Try to place the light so it's more or less centered over the pail. You should see the inside of your pail fill up with nice diffuse light.
Step 6: Position the Camera
Here you'll position the camera so that you get a good view of your object.
Start by attaching the camera to the pail with the velcro you applied earlier. Use the velcro rolls to change the angle of your camera so that the entire object is in view. During picture taking you'll take a ring of pictures with the camera at a lower position and a higher position. Try to attach the camera at the lower position for now.
Step 7: Take the Pictures.
Congratulations! Now that you've made your own 3D scanner here's how to use it:
Start by turning off flash on your camera. Using flash can create shiny spots that confuse many 3D scanners. You'll probably also want to turn on Macro mode (usually a flower icon). Macro mode will help you take focused pictures this close to the object.
With the camera ready, take a picture with the mark on the pail aligned to a mark on the lid. Next, rotate the pail so that the mark on the pail lines up with the next mark on the lid. Take another picture and repeat until you've taken a picture at every mark along the lid. Feel free to say encouraging words to your object during it's photo-shoot. :)
Once you've taken pictures at every mark along the lid, re-position the camera slightly higher and aim it at the object again. Finally, take another set of pictures at every mark along the lid.
Step 8: Create 3D Model
Now you're ready to use 123D Catch! Check out the website for use instructions and access to the web-based version or downloading the desktop version.
The screenshot above was taken from an exported mesh opened in Meshlab:
Meshlab is handy for cleaning up your 3D Scan: