IGES Export Settings tips - Any CAD System

Technote 82
Product: Advanced Milling, FreeForm Machining
Date: 06/94
Version: Up to v11.5

General information about working with IGES files.

Steps in Conversion Process:

  1. Pre-processing on the CAD System
    • Explode subfigures
    • Convert offset surfaces to spline surfaces
    • Select only the surfaces that need to be exported to SmartCAM
  2. Export to IGES from CAD System
    • Convert surfaces to IGES entity 128 spline surface types
    • Convert spline curves as IGES entity 126 (B-spline)
    • Output XYZ data (model space curves) in addition to UV data (parameter space curves) for trimmed surfaces
    • Export all surfaces as IGES entities 142/144 (Curve on Parametric Surface/Trimmed Surface), as the first preference
    • Export all surfaces as IGES entities 141/143 (Boundary Entity/Bounded Surface), as the second preference
  3. Import into SmartCAM
    • First Preference for Import Settings:

      U, V Count = 1, 1
      Tolerance = .01 inches

    • Second Preference for Import Settings:

      U, V Count = 0, 0
      Tolerance = 0.1 inches
      This would be faster, but would not be able to tell difference between surface patches and so surface picking may be difficult.

    • Third Preference for Import Settings:

      U, V Count = 3, 3
      Tolerance = .005 inches
      This would be slower, but more descriptive on complex surfaces.

    • Create a log file. Use the log file to review import error messages.
  4. Post-Processing in SmartCAM
    • Checking and Debugging the Model:
      • Use Dynamic View to review entire model, see that surfaces look connected or look like the engineering drawing.
      • Use View - Render Image for a shaded view of model, to visually inspect import.
      • Review import log file for errors or lost surfaces.
      • Review release notes for known limitations in IGES transfers.
    • Test the surface:
      • Property Chg - Surfaces to change the number of display grid curves and see if surface still looks good.
      • Use Render Image to visually inspect surfaces.
      • Use Surface Machine - Straight and verify toolpath follows the surface.
    • Replace bad surfaces with new ones or edit surfaces:
      • Mesh Edit - Generate Mesh to get a meach that covers the surface.
      • Mesh Edit - Extract - Trimming Curves to get wireframe elements from boundary edges.
      • Group Trim the mesh back to the trimming curves.
      • Create - Surface - From Mesh to create the new surface.
    • Review computer hardware setup, in case of a crash or out of memory error. Does computer meet minimum RAM and virtual memory requirements?