I worked out this rough process whilst building a replica of the puzzle box from the Hellraiser movie. (See that here: https://www.instructables.com/id/Lament-Configuration-Hellraiser-Puzzle-Box-Lemarch/ ) Various types of props will require slightly different processes and I'm sure my workflow can be improved upon - but I wanted to share what I've learnt so far. The puzzle box consisted of 6 engraved sides, so in terms of maching, it's in the 2.5D engraving category. I haven't made any complex 3D objects using this process, but I hope this Instructable inspires someone to have a go.
You will need
- a copy of the movie
- GIMP (GNU Image Manipulation Program) or Photoshop if you're going down the paid-software route
- For 2.5D relief engravings, Easel will generate G-code to cut relief designs from images. It's not a download - you just go to http://easel.inventables.com/ . I wrote another Instructable about using Easel G-code with CNC routers that don't run on GRBL: https://www.instructables.com/id/Run-Easel-Gcode-on...
- For 2.5D machining, a CNC router fitted with a V or engraving bit - I used a 0.8mm Dremel engraving bit for the puzzle box
- For complex 3d objects, SketchUp + STL Import & Export + Slic3r + a 3D printer is probably the best choice of tools. STL Import & Export can be downloaded from https://github.com/SketchUp/sketchup-stl
0:54 Take screen captures from the movie showing the prop from as many different angles as you can. On a Mac, you can just pause the movie and press CMD + Shift + 3 to capture the whole screen.
1:01 Load up the screen captures in GIMP.
1:14 Crop the images tightly around the prop.
1:28 If the prop is tilted or rotated in the frame, use the Rotate and Perspective tools to correct that. Then crop the images around the prop as tightly as possible. The aim is to get at least three clear images of the prop - from at least 2 sides, plus top and / or bottom. Complex 3D props might need 6 views - from left, right, top, bottom, front and back.
3:10 If areas of the prop are hidden in the screen captures, you can copy and paste the hidden parts from other screen captures to recreate the entire prop.
3:53 If you want to quickly engrave a design from the prop, you might be able to play with the contrast and histogram controls in GIMP to enhance the image of the design, and import that to Easel. However, the screen captures of the puzzle box were too blurred in places, so I decided to create a new layer in GIMP and trace the engraving.
5:01 For 3D objects, you can import the images of various sides of the prop into SketchUp and 'trace' the images in 3D. The hard part about this is keeping the shape 'watertight' enough to export it. When you're done, export an STL using the STL Import & Export plugin, create G-code from the STL file using Slic3r, and print it on your 3D printer.
5:28 Scaling the prop: You can scale 2.5D designs in Easel, and scale 3D objects in SketchUp prior to exporting them as an STL file. You can guess the size of the prop by comparing its size to other objects of known sizes within each screen capture. The puzzle box was often shown being held by various actors, so I used the length of the actor's fingers to estimate the length of the sides of the box.