Re:StlWork

> Date: Sat, 2 Sep 2000 15:54:30 -0600
> From: "Tim Goldstein" <timg@...>
>Subject: RE: StlWork 3D CAM program, demo now available.
>
>While I am stilly trying to understand all the great things I can do with
>the VFontz Engraving program I got last week, can you help me understand how
>this program differs from a CAD/CAM like Vector or BobCAD? In other words,
>why would I want to add this program to my machining tool bag?
>
>Also, What would be the advantage and disadvantage of getting STLWorks with
>the translator/3D modeler versus just buying the upgrade to DesignCAD 3000?

Sorry if this is too long, but Tim asks hard questions. ;-)

StlWork generates a tool path that is very similar to the 3D "SKIN" function in Bobcad & Vector. It compensates for the tool size & shape and as the cut progresses across the part in the X and Y directions, responds to changes in the surface of the part with variations in the Z height.

The "Skin" function requires a VERY specific geometry wireframe drawing and it MUST be correctly selected. The Skin function does NOT check for gouging. It works best for simple prismatic shapes and cross sections. Complex multisurfaces with many variations in heights and depths are extremely difficult to define. StlWork has none of these limitations. It can handle extremely large files and processes the surface cutting data at an astonishing (to me) speed.

StlWork requires a file in a format called STL. This stands for Stereo Lithography and is the standard format that is used for the rapid prototyping machines. The actual geometry is defined as a series of 3D triangles that are arranged in the shape of the surfaces to be made. There are many many other kinds of 3D files. If you are like me, you don't always want to design something from scratch, but would just like to make a small model of a VW beetle, or a fish, or some 3D letters for a sign, etc. Nothing super precise, you just want it to convey the idea of the shape. On the other hand, if you discovered the wreck of a pirate ship and found a silver bar that you wanted to machine....

StlTrans lets you visit the free archives of 3D shapes that are all over the internet, download a model of the thing you want to carve/cut/make, and translate it to STL so that StlWork can process the part. Typical forms that you might find are 3ds, dxf, binary STL, and vrml. Stl trans also has the ability to process USGS topographical map data and save the resulting data as a STL file. With this file you can cut a terrain map of major chunks of the world. The data is stored on the internet and much of it may be downloaded at no charge. I have a large stl map of the Grand Canyon that we will be making available at a later date. In order to make the canyon more visible, I scaled the Z depths by a factor of 10. This makes it more like a certain canyon on Mars, but it's easier to see. StlTrans has independent scaling in all axes, and can also make mirror images. It can generate 3D extruded letters from Tru-Type text, and can also produce beveled edged shapes from simple drawings produced in Cad programs like Vector. There is a provision to handle pointclouds and generate faceted surfaces directly from scanned data. A typical use that I have already helped a customer with, is to translate a Picza scanned file (DXF faces) into STL.

As far as the modeler is concerned, I upgraded my DesignCad 97 to DesignCad 3000 about 3 weeks ago. Some of the stl models that we have available on our web site were actually made with it (Hemi & Torus). However I have had DesignCad for nearly 4 years and have still not become comfortable with it. It's interface is a lot like AutoCad or Rhino, which I am also uncomfortable with. Either program is perfectly acceptable to produce Stl models for machining with StlWork. I guess I have just become spoiled by Vector. When I picked up Amapi and could produce that 3D letter, StlWork model that we used for the logo in about 1 hour, I knew which modeler I wanted to offer with StlWork. Amapi is a surprisingly powerful 3D modeler for the price. It doesn't import STL however. It does save files in STL. I even found an unwrap surface function in there to layout flat sheets for cutting and assembling a 3D part in sheet metal!

We are building web content about these programs at http://www.stlwork.com
Best Regards, Fred Smith- IMService
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