CAD.py

r rt8396 at gmail.com
Mon Nov 3 16:12:42 CET 2008


On Nov 3, 8:29 am, Eric Carlson <ecarl... at eng.ua.edu> wrote:
> Hello,
>
> I have pondered this notion of a 3d sketcher a bit myself. Before I go
> on, here is a quote from writer Neil Gaiman, author of some very good books:
>
> "Every Published writer has had it - the people who come up to you and
> tell you that they've Got An Idea. And boy, is it a Doozy. It's such a
> Doozy that they want to Cut You In On It. The proposal is always the
> same - they'll tell you the idea (the hard bit), you write it down and
> turn it into a novel (the easy bit), the two of you split the money
> fifty-fifty"
>
> In this spirit, let me offer the following observations/suggestions:
>
> Mayavi, the open source data visualization system from enthought.com,
> does a very nice job of high-level wrapping of The Visualization
> Toolkit. VTK has both high-level wrappings of OpenGL for display, as
> well as many modules to import/export various 3D file formats, merging
> or clipping 3D objects, constructive solid geometry, etc. All of the
> lower-level VTK routines can be accessed through the traited VTK wrapper
> (TVTK) from enthought. Once you have a Mayavi scene, it is a simple
> matter to add anything to it, or to modify any of the objects in the scene.
>
> Although Mayavi has evolved to be reasonably backend independent, the
> current version interacts most easily with the wxpython GUI toolkit.
> Given that they work well together, I would say that a combination of
> wxpython, Mayavi, and enthought Traits (recent stable versions and
> Python 2.5) could lead to a very interesting 3d sketching application.
>
> If you install the wxpython demos and samples (an absolute necessity if
> you program with wxpython), you can dig through the installation
> directory and find a "samples" subdirectory, and in there you can find
> another folder called "pySketch." This app is a nice 2D sketching
> program with everything I really need for simple 2D sketches, except
> rotating objects (and I had to hack it to get a button to save an image
> and copy to clipboard) - it could probably also use buttons for various
> common drawing objects. If nothing else, this example might give an idea
> of a possible layout, and source for how to set it up.
>
> For the 3d sketching, you would have to have some buttons for object
> creation (various polyhedra, sphere, ellipse, arbitrary explicit
> function, implicit function, constructive solid geometry surface, maybe
> a library of predefined widgets), extruding, surfaces of rotations,
> button or menu for importing/exporting an object, some buttons for
> clipping and merging objects (additive and subtractive merges), some
> buttons for object transformations (scaling, rotations, precise
> placement in a scene, parametric stretching, twisting/turning, mirroring
> objects), button for duplications, and buttons for setting object
> materials/colors/properties.
>
> There are many examples of embedding a mayavi scene in other
> applications given in the examples directory at the mayavi/tvtk
> developer repository.
>
> Also, I have come to appreciate very much the wxpython AUI managed
> frame, which lets you move panels, toolbars, whatever, to pretty much
> any location within your frame. This means that anyone using your
> application can customize their layout with trivial effort.
>
> I doubt that I can get around to any of this until late next year, but I
> would be happy to assist if you want to take a shot at it...
>
> Cheers,
> Eric Carlson

i don't see the gui as a problem, and i think using a toolkit would be
a good
idea at this point to get things going quickly.
i have looked at vtk and it looks promising.



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