Upper extremity modelling with Spatch and HamaPatch

Spatch is a free 3D surface modelling program for the PC which has special application to anatomy drawing. The program is small (1 megabyte) and its .spt data files are tiny compared to other 3D formats such as .dxf or .obj. It is brilliant in its simplicity. Unfortunately, its author, Mike Clifton, and its original home page have both disappeared from the internet. I have posted a copy of the program here

An archive of hand .spt files is available here (work in progress). 

The program works as follows: the user constructs shapes from splines (lines connecting dots) as for the images here:

Complex mesh constructions can be made and modified, then rendered as 3D smooth surfaces by the program:

These can be spun around in real time and easily modified. The slick thing about this program compared to others is that few actual control points are required to create complex shapes.

There are a few electronic anatomy image resources, such as Primal's Interactive Hand, but this supplies only static images, such as the ones referenced on this page. As such, they have limited usefulness.

Here, the distal end of the humerus has been modelled in two (articular and nonarticular) 3 dimensional sections which overlap: The articular surface is easily defined by 22 control points.

It doesn't take much time playing with the program before it becomes obvious how very complex organic shapes can be generated from very few points of information - just as living shapes arise from a few genetic control points - just as all shapes are created during embryonic through only two processes: extrusion and invagination - the same effects that the control points have on the surfaces you create! It is a transforming experience to construct anatomic models with this realization in mind. Try it!

The same model, rendered by the program. This model was used for the diagrams in this page.
amapatch: Hamakazu's Hamapatch is the next generation of sPatch. It is also free, works with the spatch file format, and has many great additional features, such as allowing you to work with simultaneous wireframe and visible surface renderings in real time, choosing different colors for different portions of the model, and a number of other helpful featues. Hamapatch is available here. The site is in Japanese, but the download file includes both English and Japanese versions. If the site is down, I have posted a copy of the zipped file here. The English version does not yet have a working help file, but Jonathan Lee has compiled an excellent help file, posted here. Hamapatch is still under development, but is truly amazing in it present form. Also amazing is that the entire (zipped) program is only 353 kb! Small is beautiful.
The file for that image, humerus.spt, is 11 kb.  In contrast, the dxf version of the same surface is 1837 kb, shown here in another program:
I hope to develop a library of sPatch based upper extremity models. Here, the proximal, middle and distal phalanges of a finger, in wireframe, and rendered from the file phalanges.spt
These models can be exported to a variety of formats, including DXF, POV-ray, Renderman, VRML and others. This allows them to be painted or viewed from any angle or point of view as was done here with Amorphium

Or animated, as was done here using Poser 4. (...hmmm, still needs some work...)
Models: Other sPatch links:

Hamapatch links:
3D VRML anatomy sources  http://www.people.nnov.ru/fractal/VRML/Splines/Splines.htm

If you are interested in collaborating on anatomic sPatch / Hamapatch models, please contact me.

Charles Eaton MD

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