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Outline Projection Device

Transfer the outline of an object on to an irregular surface
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A series of lights approximate the shape of an object and project that outline on to another object.

The purpose is to create an approximate visual representation of where a physical object would intersect with another physical object if the first object were to pass through the second object. It would essentially project the silhouette of an object on to a surface: a sort of 3D to 2D to 3D converter or contour guage with an extra dimension.

A set of tubes, say 2 or 3 mm in diameter and 100 - 200mm long. would have a light source at one end; probably an LED. The tubes would have an appropriately shiny/matte interior to cause the light source to project only a defined, small circle on to a nearby surface. (It may be necessary to use a better collimated light source like a laser pointer.)

The tubes would be arranged parallel to one another with both ends aligned. The ends containing the light sources would all point the same way, in this side-by-side arrangement.

The tubes would be bound together in this arrangement by a hinging structure. The tubes would hinge with respect to one another while remaining parallel.

(Hang on, it'll hopefully make sense in a second.)

An example of the implementation and application:
Say you had a sheet of metal through which a circular tube was to pass at some angle other than perpendicular to the plane of the metal and it was your job to cut the hole in the sheet metal.

Wrap the shape transfer device around the tubing and turn on the light source. With the tubing at the appropriate position and angle to the sheet metal, the approximate shape and size of the needed hole will be projected on to the sheet metal in the form of a bunch of dots of light. Connect the dots to draw the shape of the hole to be cut.

That's a very simple example of the application. I was looking at a more complex scenario when I came up with this: cutting a battery box in to the curved, convoluted stamped steel inner fender well of one of my old trucks (that whole under-the-floorboard thing is sooo '50's).

half, Sep 21 2005

Hmm...I may not be so afraid of the laser pointer angle after all http://www.instapar...0pcs-r-laser-m1.php
10 units for $17.00. The diameter of this (or an LED) is a concern. Bigger diameter means center of beam farther away from edge of object being traced:. less accurate projection. [half, Sep 23 2005]

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       This would be the most cool thing in my garage, by far.
reensure, Sep 21 2005
  

       Wot, no marker attached laser projector / camera to map the surface or the penetration object, no fancy multi-element laser beam shape projection algorithm to project the desired shape on the acquired surface, no super-dooper high powered laser to cut out the shape… No lasers! Erm, just as well. Your device appears a tad more user-friendly. Best of luck with the truck.
Shz, Sep 22 2005
  

       [Shz], don't think that I didn't go there. Thanks, maybe you can help out when you come for that bike ride. :-) Though, I do have a ways to go before I'm up to modifying the fenderwells.   

       Thanks for the feedback, [fq...]. At the moment, without any proof, I could be persuaded to disagree that laser beams would be necessary. I based the design partially on some makeshift theatrical spotlights that I've seen built from off -the -hardware -store -shelf parts. I probably would only need to project the shape over something like a 30 cm distance. I'll have to check it out.   

       I think it's buildable, but it seemed like it would be fairly expensive with quite a number of secondary operations to perform. While I was writing, I think I may have come up with a way to simplify the construction considerably.
half, Sep 22 2005
  

       Ahh!   

       I get it. It made no sense earlier.   

       Let me explain in dummy-terms:   

       It displays an undistorted outline of n object to where it would be if you translated the object in the direction the lights are pointing.   

       Think those nail-toys, the one where it keeps an image with thousands of small blunted nails. Except with light.
DesertFox, Sep 22 2005
  

       Tidy, very tidy.
Dub, Sep 22 2005
  

       //don't think that I didn't go there//   

       Not for a second.
Shz, Sep 23 2005
  

       Makes me want to build a Why Didn't I Think Of That stamp.   

       +1
po, Sep 24 2005
  
      
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