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REFLECT CURVES - V4
By Tom Cisler, Matra Datavision

What makes a good surface a GREAT surface? A good surfacer knows this means one that has been properly and thoroughly analyzed. A good way to do that is to use REFLECT CURVES.

Reflect curves simulate how light bars will move across the surface. By placing a number of these on a surfaced object, the designer can determine several things about their geometry:

• Surface Quality - by observing how the curves flow across a surface, indications of surface quality can be determined. If fluctuations are observed in a reflect curve as it moves across the surface, a surface flaw may be indicated. This might have been caused by a problem in one of the curves used to construct the surface.
  
  
• Surface to Surface Continuity - just because surfaces are of high quality, doesn't mean they have proper aesthetics. By observing how a single curve passes over a surface boundary indicates how those adjoining surfaces will look aesthetically.

Three possibilities exist:

1. No reflect curve connection - surfaces are either non-connected or non-tangent.
2. Reflect curves are connected by not tangent - surfaces are only tangent.
3. Reflect curves are connected and tangent - surfaces are tangent AND curvature continuous.

Getting surfaces to pass #3 is absolutely necessary for highly visual parts. If your data is to be sent to an OEM, you had better understand this technology.

Reflect curves are created using either CURVE1+REFLECT or Real Time Analysis. In both cases, three pieces of information are required:

1. Line of sight - this is your direction of view for the object. Many times this will be a line that views the objects from the side.
2. Surfaces (or faces) to analyze.
3. Reflect angle - you normally begin at 0 and increment at even angles values until 90 degrees is reached.

Remember, when using CURVE1+REFLECT, new curves are created in the model. Make sure to use a "junk" layer in order to dispose of them later.

Ordinate Dimensioning in CATIA V5
By Tom Cisler, Matra Datavision

It is possible to make CATIA V5 Cumulative dimensions look like ordinate dimensions. Here are the steps to do that:

In the folder ...\Program Files\Dassault Systemes\B05\intel_a\reffiles\Drafting there are some drawing standards files. This example will show you how to edit the ANSI drawing standards.

• Make a backup of file "ANSI.CATDrwStandard" before editing
• Edit this file with Word pad with the following settings:
• CUMLSignDisplay,1 (for no display of +/-)
• CUMLOriginSymbol,0 (for none)
• CUMLSymbolScale,1 (to set scale)
• CUMLExtLDisplay,NO (for no extension line)
• CUMLZeroDisplay,NO (for no origin "0")
• CUMLTxtReference,2 (locates dim value to extension line, not dimension line)
• CUMLTxtOrient,1 (orients dim value parallel to extension line)
• CUMLTxtAngle,0 (sets degrees of rotation of dim value if needed)
• CUMLDimLDisplay,1 (sets no horizontal dimension line display - !!!)

These procedures are the same for all the other drawing standards files in that directory (ISO, JIS, CCDANSI, CCDISO, CCDJIS) if you wish to change their settings.