Intro: Super Personalized Shadow Casting Candle Holder
This personalized candle holder displays a silhouette of my family on the wall and some text on a table using only the light from a little tiny votive candle. If done correctly, the shadow will be indifferent to the specific height of the wick and flame (within the typical sizes for votive candles that is).
Instead of hanging a photo with nails, or a mural with wallpaper/paint, the candle holder...and thus the shadow, can be swapped out easily for different occasions, even during the daytime hours!
Also note that I rely heavily on annotating my images in this instructable since the easiest way to see what I’m doing is with a screen capture (Shift-Command-3), upload, and click for an instant note. Except for a few rarities, every image is tagged somewhere, so if you see a blank one, look for a itsy square crammed at the top of the image. Sometimes, I see this happening on both mine and other’s ‘ibles and I don’t know why. Clicking on the next image and then going back sometimes repairs the problem.
Parallels 7 running Windows 8 (AutoDesk is working on a Mac Version of 123D, but not yet out)
Step 1: Decide on an Environment for Your Shadow
Most shadows have a common feature in that they all consist of an outline that's darkened in the middle. With reflection, multiple or broad light sources, soft edges, or translucent materials, other effects can occur, but for this project we will consider only a well defined shadow shape and an opaque blocking material.
The lighting and environment all need to be thought through and will determine the form of shadows that you can create.
You are not limited to a single surface. Actually, you can project a shadow through multiple rooms in your house that only makes sense from one perspective if you like (example: http://www.archivenue.com/wp-content/uploads/Geometric-Illusionary-Perspective-Paintings-1.jpg). Cast it on the ceiling, or both the table and wall simultaneously as I did.
Consider permanent obstacles, such as the chair in my photo...or dynamic ones, such as a person if they happen to sit in said chair.
Step 2: Design Your Scene
I used 123D Catch for this. Application notes:
- Watch out for shiny objects, like the metal container of a votive candle, or the reflective surface of a polished table.
- Make sure your scene has lots of detail. I had to reduce the detail because of the shiny table, but added written text in hopes of making up the difference. The white spots are holes in the resulting mesh, because the software didn’t know what to do with it.
- Take shots from all angles to minimize vacancies in your mesh.
- Keep only the important things in your scene. You may want or need to import the entire room, just crop away the rest.
- Export the file as an .obj
Step 3: Detail the Shadow Drawing
Also, the objective is to bring out recognizable features in binary (shaded or unshaded), that are normally easily discernible in color. By post processing your images, it's easier to see what is important to trace, and what can be left out.
The order I used:
- Pencil Sketch
- Maximized shadows under Tuning
- exported as a .PNG
- imported onto a canvas in 123D
Step 4: Fix Your Model's Coordinate System
Create a new 123D file by opening the .obj scene created earlier in Catch if you performed that step. If the mesh was not scaled already in Catch, you need to do that at this step. I knew that my final solid should be under 3x3x3 inches, and my votive candle has a diameter of 1.5 inches, so I drew a three inch square and 1.5 inch inscribed circle and then scaled the candle to fit the circle. I also knew the height of the wick as a backup. It is best to scale it in Catch first though. They have videos on how to do that here.
You may adapt this whole instructable to suit your project, but I reference the base of the candle axis as my 0,0,0 point.
Step 5: Create a Canvas for Sketching
Construction of work axes and planes are your best friend for this project. Understanding how the various options can clarify your virtual environment will make your experience less frustrating. I used an offset plane to place my canvas on. For the portrait, I wanted to cast the shadow on my wall, so I needed a plane parallel to the xz plane and 70 inches away. I turned off the visibility of every other component in 123D and then placed my canvas using the .png image created with Picasa.
Step 6: Work the Working Axes
Although you CAN loft from a feature to a point, I always had bad experiences with it. Some of the steps later described here are a result of trying to fix a point lofting error.
So, the safest way for more complicate shadows involves creating a work axis connecting a point light source to a distinctive point in your sketch. I use at least four: bottom corners, apex, and some other feature, like an earlobe. These will allow you to copy your portrait sketch, shrink the copy and position it along the optical axis perfectly. The work axes should go though the identical points on your copy as on your original. Nudge the copy until it does. Make sure you rotate around and the work axes still go though the correct points.
The copy must lie within the part that will create the shadow!
I believe that I eventually scaled my copy to 0.1 or .06 of the original.
Step 7: Add Any Additional Shadows
Text seemed like a cool idea, but it didn't go as smoothly as I dreamed. As of this writing, 123D scales text not by points or pixels, but by whatever units you are working in. So, naturally, I picked my font with a scaling of 8.....inches! Ah!
With eight as the lowest value that I could choose, the letter "H" in Happy Mother's Day was already twice larger than the entire sculpture. I wouldn't be able to fit "Happy" on my dinning room table. So I conceded to sketch the best I could the words I wanted to display. They also aren't floating, but grounded to the candle holder. This means that the shadow traces back to the base of the candle piece. Floating is more challenging because your support material will create a shadow. It must be included, and I didn't want to work that out at this point.
Use work axes the same way to position a copy of the text for tracing the projection backwards to the candle flame.
Step 8: Loft, Loft, Loft
- Select Create->Loft, or right click->Solid Features-> Loft
- Select the intended shadow surface as profile 1
- Select the copied surface as profile 2. Use the swap option using the orange star icon if it shows centerline instead of profile.
- Chose New Component instead of Join
Press Enter, or right click->OK
Step 9: Frame the Candle Holder
- I started with a flat square base 3X3 inches, then extruded it 1/8".
- Inscribed a 1.5" diameter circle and sank it 1/16” for the candle to set in.
- Sketched a 1/32” radius circle onto the top surface of the base and extruded a cylinder up to 3”.
Made arrays and randomish replicas of this cylinder until the entire top surface was covered. Enough posts to block all light leaving radially from the candle at the center.
- Avoid Parent/Daughter dependencies if multiple independent patterns are made
- Choose for each case whether the patterned components should be new components or joined. Joining reduces further editing freedom, while a long list of independent components accompanies headaches when your processor slows down. (whether visible or hidden)
Step 10: Finalize the Full Shadow Volume
Riddle #2: Does the light have a volume?
Riddle #3: Could you subtract one to get the other?
Up to this point, I haven’t explained how the lofts modify the scatter of posts that will ultimately create the desired shadow. The sequence:
The different loft segment faces are separately selectable, just as in the first above image in this step. You can “fill out” the remaining volume between the lofts by extruding these faces some exaggerated distance. The overlap is important, not how far beyond its extended. If you understand the rational behind what the lofts are for, and why we can use them (for angles, not absolute scale), then you will easily see that an extension in the right direction will have no negative impact on the final product.
Again, for additional explanations, review the uploaded images with notes.
Step 11: Connect Disconnected Pieces
If you made vertical posts like I did, then think vertically, 'what posts are affected with an horizontal cut?’ Then,
- Sketch a path that connects all the affected posts with nearby unaffected ones.
- offset the path using Sketch->Offset
- close the path by drawing lines at the ends
- loft to a point or a copy to ensure all of the affected posts from front to back are secured
- Push/Pull the end faces to meet up with the innermost and outermost posts
- Stare at your masterwork for at least a minute with watery eyes if thats an option
Step 12: Command P
Although it shouldn’t be necessary at this point, you must ensure that all of the items that you want printed are combined into a single piece. This is accomplished as before with the Combine->Join function.
Export your file as a .stl
Currently, in 123D, you must first sign in with a username and password to enable all of the Save As options.
Now you are ready to print. Several 3D printing services are available online, or if you are lucky to have access to your own printer, you could print out several versions of your own Super Personalized Candle Holder or make them for others.
Thanks for your comments on this Instructable’s clarity and room for improvement.
I will upload an image of the actual shadow as soon as one is available. The speedy draft print didn’t include the internal cuts that require higher resolution.