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Feature coordinate system vs. global


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more importantly, i would like to know why calypso always defaults to feature coordinate instead of base align when dealing with measuring strategies.
Like i get that someone at some time may have needed data that way, but why do 99.9% of the rest of us have to constantly toggle into base in order to edit manual points?

We don't all make cubes & washers for a living!
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I think he means why isn't each feature's coordinate system rotated so that its axes are parallel to the corresponding axes of the base alignment. In his image, feature axis X lies parallel to base alignment y, etc.
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Are you talking about with Planes and Polylines? I think that it helps when modifying those strategies when they don't lie parallel to an axis.

The thing that has always gotten me is points that are perpendicular to the spatial axis being in a weird axis when trying to report the Polar Coordinates.
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I'm not at a CMM right now to confirm it but I think in the feature coordinate system the Z axis always marks the main vector, i.e. the surface normal for planes and the direction af the axis for cylinders, cones etc. A more interesting question is how Calypso determines X and Y of the FCS. For some features there's an explanation in the help file, but for others I'm still not sure after 12 years of Calypso 🤣
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Michael is correct with interpreting my question. And Norbert, in the image that I shared the feature in question is a line on the side of the part. The plane that the line falls on has a normal in BA+X, the FCS transforms that normal to Z. But what is interesting is what you say. The feature itself, the line, falls along FCS+X. So in reality, the line lies along BA+Y.

I'm trying to determine Zeiss' criteria for these transformations. Does it only apply to lines? Is the FCS a transformation of the BACS such that the +Z lies along the normal of the surface that the feature falls on, but not necessarily the feature itself?


BA - Base Alignment
CS - Coordinate System
F - Feature

377_046319ee0e7c2249da51f541e414843f.jpg
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Is it a 2D line? If so, this one has a "secondary direction" which is the vector of the probed points, or in other words the normal of the surface it lies on. So it may be that for 2D lines Zeiss chose Z to be the point vectors instead of the line direction. But I would guess that for a 3D line FCS Z is the line itself.
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I'm pretty sure it's using the bounding box created by the CAD program, not Calypso assigning the coordinate system. That's why if you manually probe something it will often come up with a different coordinate system than if you extract the same feature from the model. I don't know this for a fact, but it makes sense to me based on my CAD background.

Robert
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