Re: RE: How to go from 2.5 D to real 3 D ??

> Date: Thu, 22 Nov 2001 12:27:26 -0500
> From: "Gail & Bryan Harries" <gab@...>
>Subject: RE: How to go from 2.5 D to real 3 D ??
>

>Can you tell me the major differences between the CAM side of Vector and
>what STLWorks offers... would Pro/D and STLWorks give me a better
>combination than the Vector CAD/CAM package?
>

StlWork (singular please no s) complements Vector. I specified Stlwork to mesh with the capabilities of Vector. There is very little over lap between the two programs. StlWork is strictly a 3D program and any 2 1/2 axis type of process is accidental. It does no design, but rather develops tool paths from existing designs, created in 3D CAD programs that can create a "solid" kind of format and save it as an STL file(like ProD or Rhino). The STL format was developed to be used for input to Stereo-Lithography, rapid prototyping machines. We(and many others) have taken the same file format and used it to create tool paths. The file consists of many little triangular facets, arranged in such a manner that from a distance they appear to be a smoothly curved surface. The size of the triangles can be varied to represent whatever level of accuracy you want to define for the surface tolerance. There are many file formats that are similar to STL, including 3Ds, DXF- 3D faces, VRML, etc.

StlWork creates raster tool paths, those that go back and forth in X or Y, as well as "Waterline", those that start at the top of a model and define the line of contact that would be created if the model were partially submerged in water, and then precisely moved to shallower and shallower positions under the water, until the entire model was removed from the water.(these are much more efficient on most desktop and hobby class machines because they only use the X&Y for cutting, using the slower/weaker Z axis only for positioning between the rings) It can accurately offset tools with flat, ball, bull, or conical shapes and performs continuous gouge checking in all directions. It allows you to select portions of the model to machine by defining limits in X, Y, and Z for various kinds of cutting, whether roughing with large flat cutters, or finishing with small radiused cutters. You can combine these different strategies and tools to make a complete program to carve your masterpiece.

At the present time (I keep dropping these hints) Vector can create 3D programs from wireframe boundary curves (similar to coonspatch), and has some additional capabilities for developing waterlines for swept curve pockets. There are drawing functions that create original wireframes and then tool paths based on the wireframe definitions. It is an excellent program for making what are called prismatic parts. Those that have edges, whereas StlWork is more for creating parts that have no edges, but rather consist of many complex geometries blended into a single entity.

As to whether one combination or the other is better, it depends on what kind of parts you want to make. If you want to do artsy-fartsy stuff with swoopy, convoluted surfaces, go with the StlWork type of approach, and a 3D modeler. If you want to machine slots, pockets, chamfers, drill holes and optimize the cutting order, go with Vector. Vector can also take the slices of a model produced by StlWork, as a DXF file, and create G-code from them, either as standard 3D, or as rotary 4th axis. We call this the Totempole in StlWork, because that is one of my projects, to be able to design and machine a totem pole with my rotary 4th axis. This is a special case in which the two programs work together to create a specialized kind of output.

Best Regards, Fred Smith- IMService
Listserve Special discounts and offers are at: http://209.69.202.197/cced.html