New STL format

Date: Tue Jun 02 1998 - 09:44:46 EEST

     To list,
     Albert Young said: Basically, we began with the HPGL language
                         utilizing such commands as X, Y, Z, pin-up,
                         pin-down, and speed, and then we added line
     A question for Albert: HPGL1 or HPGL2?
     Concerning a new STL format, To my knowledge, every 3D CAD system,
     surface modeler and solid modeling system can output an HPGL or
     PostScript format plot file and most if not all can produce an
     accurate slice or cross section through the object or objects in
     native format. Most of these same programs can support the
     color/texture information used in photorealistic rendering. So...Why
     not use the CAD/Sculpt/Modeler program to create the data set for the
     machines to follow instead of re-inventing the wheel?
     As the "layer thickness" of many of the current machines gets smaller,
     the need for extra information in the build file is being eliminated.
     Near flat and flat triangles become meaningless if there is uniformity
     in the fill/hatch and overlap in the boundry trace, so why not just
     define the boundry only.
     The data defining the fill/hatch should be a constant (material
     specific table) within the machine that is called for by the boundry
     conditions of that layer. (Different material properties from the same
     resin for each part?)
     The photorealistic attributes of the object could then be mapped to
     the slice/section as the slice is generated, and either added during
     the build by a secondary coloration process or by means of resin
     material science (dyes sensitive to threshhold levels of energy or
     frequency could be in the resins).
     The result is that the triangle approximation of the contoured surface
     is eliminated and you are working with the model in native format so
     design changes re-use the existing data sets.
     What am I missing? The model accuracy (shape, color, texture,...) is
     now a function of the design software. The machines that produce the
     parts are then just like the 2d printers of today, if all you want is
     black and white at 200dpi, that's what you buy. If you want high speed
     realistic color output you pay more and buy a faster/higher resolution
     Larry Blasch
     System Administrator for Engineering Services
     OPW Fueling Components
     P.O. Box 405003
     Cincinnati, OH 45240-5003 USA
     Voice: (513) 870-3356
     Fax: (513) 870-3338
     Disclaimer...The views expressed are personal opinion and not those of
     OPW Fueling Components.
     * "Always remember you're unique, just like everyone else." *

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