AutoCAD to SmartCAM
(via CAMAX Modeler)

These are the procedures for conversion and import of AutoCAD solid model files into the SmartCAM software for automated machining of parts in the UCB Physics Department machine shop.

The general idea here is to construct two types of file: one for the human and one for the software. The human understands 3-D solid modeled parts better than 2-D projections while the software does not understand anything but properly prepared 2-D line (not surface) drawings in DXF format. Thus the task at hand is to build a solid model file of the assembly, and each part as necessary, and a line drawing DXF of each surface to be machined of each part to be made. If a part needs machining done on, for example, the front and side, then two drawings will likely be needed (unless one of the surfaces needs only trivial machining). On the other hand if machining needs to be done on opposite sides, say front and back, then it may be desireable to show the surface with the lesser machining as a hidden line projection through the more complicated surface. However, you should take care not to compose the two sides as a projection if doing so makes the drawing confusing.

Example movie


  1. Prepare the AutoCAD model parts:
    1. Generate 2-D section slices from solid model under AutoCAD global coordinate system. This process is done to insure that the coordinate system of the surface is correct --we want no back surfaces. Ideally we would have a section through each portion of the model that has a change in cross-sectional shape but you should do whatever seems to most clearly represent a 2-D top (side, etc.) drawing of the part.
    2. Place each slice on its own (properly named) layer.
    3. Position 2-D section slices and models:
      1. Position all section slices at Z=0. We want all of the slices to be on the same plane --vertical displacement is not desirable.
      2. Position the entire parts group (slices and models) on the XY plane:
        1. Lower left corner of parts group's bounding box at origin for non-radial/asymmetric parts. Position non-symmetrical parts such that there are no portions of them with negative coordinates.
        2. Center at origin for radial parts. It is OK for parts that are simultaneously symmetrical in X- and Y-directions or with radial construction to have portions with negative coordinates provided that the origin is located at the center of symmetry.
    4. Save the file. Save the AutoCAD file with all the new slices and proper positioning. Rename it if you want (your call).
    5. Perpare for DXF Export:
      1. Delete all the solid models from the AutoCAD file so that there are only the cross-section slices remaining.
      2. Delete all unused layers. Clean up stray objects if necessary at this point.
    6. Export the DXF:
      1. Export an R-14 DXF format file using following export options:
        1. Select elements. We want to export no more than what we see and select.
        2. ASCII format. This seems to work better than binary format.
        3. Use no more than 8 characters plus the .dxf suffix. Do not use any odd characters in the DXF's name.
    7. Close the AutoCAD file without saving changes. We want the solid models, etc., in the AutoCAD file but not in the DXF.
  2. Prepare the DXF:
    1. Move all parts to layer 0. We do this because when a DXF has more than one layer the CAMAX Modeler software creates a copy of each part for each layer and then puts them all together on one layer. This is really bad because it makes sequential segment selection for tool-path creation in SmartCAM impossible so we want it to never happen.
    2. Delete all layers other than 0. We delete all layers but 0 because we want only one layer and layer 0 can not be deleted.
    3. Remove all surface information by exploding all parts. For some reason the CAMAX Modeler software does not understand parts with surface information even though it has an import option to ignore surface information.
    4. Remove all redundant line segments. If two sections share a common edge then there will be two line segments along that edge: delete one of them, etc.
    5. Format all back surface derived information as hidden line. If your part needs back surface machining, and both front and back surfaces are represented on the same drawing, then this step is important if you want your back surface machining to be done on the back surface.
    6. Save the modified DXF. Either as a new file or overwriting the old one --your call.
  3. Transport both the AutoCAD and DXF files to the machine shop.
  4. Import DXF to CAMAX Modeler
    1. Import the R-14 DXF using following options:
      1. Ignore Surfaces = ON
      2. Include Polyline Approximation = 0FF
      3. Drafting Options:
        1. Ignore Annotation = ON
        2. Ignore Viewports = ON
    2. Export FFM file:
      1. Export the FFM file to SmartCAM using following options:
        1. FFM (Free Form Modeler) Format
        2. Entire Job
  5. Import FFM file to SmartCAM

Go up one level.

Page first created Wednesday, May 17, 2000
Page last modified Tuesday, March 27, 2001 2:07 PM