Step 3: copy, paste, shrink, loft

Every part of this instructable leads to this step.
If the sketch that you made from tracing or otherwise is copied, it can be used to create a solid feature.  This copied sketch is pasted onto another parallel plane, then shrunk and positioned inside the guide/working axes.  The reason that a duplicate sketch is used instead of a point, is that even though your light may be approximated as a point source, lofting doesn't like it.

Guide lines are produced starting at the light source and leading back to the original sketch (the shadow).  I simply created a point in space that aligned with the utility flashlight bulb and connected itto points on the edges of the sketch using Construction->Work Axis-> Axis by Two Points.

Four lines are enough, assuming they are at the farthest, nearest and widest parts of the sketch.

You may think that projecting a sketch onto another surface will work, but only if your light source is the Sun in which you can very easily approximate the rays as parallel.  For far away lights, this is also true, but your shadow may be blurrier.


<p>Sorry for the reviving an old instruction, but wondering if it would be possible to update this with current tools. 123D seems to be lacking some of these features now - wondering how to do this in 3dmax or fusion 360 (or other)?</p>
hmm. As I currently use Fusion 360 almost exclusively, that seems like a good idea. Is this for something specific you are trying to do? I've made other items since then and have discovered a few more details that impact success, but I don't know that I can commit tremendous time to another instructable right now. Could interact with you directly in the meantime though. Would make for a better instructable in the future that ways as well.<br><br>see attached images for a puzzle I made for someone. when the blocks are not rotated or placed on the wrong posts, the shadow is garbled. Here it shows 825. The &quot;simple&quot; blocks are disguised and tricky to predict the shadow when looking at them individually.
<p>Yes - I'm working on a particular project that I think this technique could dramatically simplify. I'd greatly welcome any guidance you may be able to offer - my email is my username at gmail.</p><p>thank you!</p>
What material would you use to print this? Does it need to be a black plastic, or would an opaque white work as well?
I think they used Objet VeroWhitePlus FullCure835 on my other instructable, which is not&Acirc;€&Acirc;™ black. It <em>is</em> opaque though.<br>
Very cool idea. Well done!
What a good idea.

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Bio: Experimental physicist
More by hendersonjase:Super Personalized Shadow Casting Candle Holder Generate a unique shadow casting sculpture 
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