Turning Archive 2007

John Lucas - InsideOut simulation *PIC*

JKJ in East TN
>John L.,

While watching your inside-out demo in Knoxville, it occurred to me that it should be possible to use 3D modeling software to simulate and test inside-out designs before mounting the wood in the lathe. (I did 3D modeling/animation work for years before retiring this past year.)

Between feeding the horses and pickling okra tonight I made a simple test based loosely on your demo, with the results in two included images. (Actually my wife is pickling the okra at the moment while I'm goofing off here at the computer.)

The first rendered image shows the initial block of wood in blue. The yellow lines indicate the crossection of the inside shape to be cut away (along with the centerline), equivalent to the paper patterns you showed us.

The second rendered image shows the four quadrents reassembled, the yellow 2D outside shape to be cut, and the result.

The images here don't really do the method justice since the 3D model can actually be interactively rotated, zoomed, and disassembled for examination.

This modeling method not only makes it easy to visualize exactly how much wood will remain in critical areas (I almost "cut" through on my first attempt!), but clearly shows the how the inside void will appear on the surface along with any distortion introduced by the outside shape. For example, it is surprising how large the heart-shaped holes appear compared to the holes on the reassembled block. (But I see now, the void is larger towards the center so the deeper you cut, the larger the surface shape.) It should be possible to interactively "tweak" the inside shape to give the exact final shape desired.

The model also makes it easy to see exactly how the "floor" and "ceiling" will appear.

When I actually get around to trying an inside-out piece with real wood, I suspect this 3D modeling method could save a lot of frustration and a few trees.

Good clean fun! Thanks again for the demo.



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