Cartesian Distance ???

[[To...]]

I've been led to believe Cartesian Distance uses certain rules such as the distance is from the mid-point of feature one, perpendicular to feature two, which is similar to a Perpendicular Construction. However, if I need the distance from a plane to a cylinder, I cannot assign the cylinder to feature 1 and the plane to feature 2, though I am able to do the opposite.

Would someone please explain the logic to this?

What happens when it is 2 cylinders with axes at 90° to each other, i.e.Cylinder1=ID along X and Cylinder2=along Y direction, offset in Z?

[[Je...]]

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Tom,

I have been led to believe that cartesian distance for cylinders is evaluated from the cylinder's feature origin rather than a centroid, etc..

Then again, I was led to believe that Kirk Cousins would take the Vikings to the Super Bowl, and that has not happened yet, so you may want to verify this.

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Jeff Frodermann
Meier Tool & Engineering
Anoka, Minnesota

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[[Ro...]]

I was told by an old Zeiss (inc) programmer not to use planes or cylinders for distance.
Intersect them with something and use a point whenever possible.

I have also started using "Caliper Distance" instead of Cartesian, i just like that caliper distance seems to follow the base alignment, and 2 points anywhere on the model can be measured X,Y, or Z from each other, square to the base alignment.

[[Ro...]]

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Same goes for Planes.
The "height" of a plane isn't the best fit or sum average of the points, when the plane is created and all the AB&C rotation is figured up, the height of the plane is the location of the trihedron, which may actually fall off the part on non square parts.

[[Je...]]

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I totally agree, Roberto. It's best to use a projection, create an intersection or some other method for constraining the origin of a plane or cylinder. This is why I've also switched to the caliper tool in Calypso for nearly all distance measurements.


Jeff Frodermann
Meier Tool & Engineering
Anoka, Minnesota
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[[Mi...]]

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That $35,000,000 cap hit is a doozy, you think they will roll with Mond or take someone in the draft? A lot of my Minnesota friends say give Mond 2022 and see what happens. You never know, with a new GM you might get Rodgers just like Farve. 🙂 🙂 🙂 🙂 🙂

[[To...]]

I don't necessarily agree or disagree with anything you guys posted

For discussion, let 's say the plane is the end face of the X axis cylinder and they use a position from the end face for the X location of the Y axis cylinder (shown in Jeff's sketch), I assume nobody would argue with using the plane as the Primary datum. This would be similar to sitting the end face on a surface plate and measuring the cylinder location with a height gage. If I use a Caliper Distance, it would be relative to an alignment which might be okay for some situations but not for the above. I understand Position and Cartesian Distance are two different things.

Look at the presentation (Perp vs Cart Dist.pdf ) comparing a Cartesian Distance and a Perpendicular Construction. We see that the order of the features in both determines which evaluation is made. With 2 planes, you can see the first plane uses the mid-point and the 2nd feature establishes the orientation and that Cartesian Distance and Perpendicular Construction net the same result. The Perp Constructions gives us 3d Line that can be used for some other evaluation.


Note: the plane in the following example is not perpendicular to Datum A as was discussed at the beginning.
In the Perp Const_Plane v Cylinder.pdf shows similar behavior. Each page shows a view from -X and +Z. This is why I was asking why can't I choose the cart distance from cylinder to plane.

Perp vs Cart Dist.pdfPerp Const_Plane v Cyl.pdfScreenshot 2022-02-04 114406.jpg

[[Je...]]

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Good question, Mike. Being a Vikings fan means learning to live with heartache. I think we're heading in the right direction with the new GM, though.

How about you send us Tyler Huntley and two first-round picks for Cousins? Better yet... Huntley and Jackson for Cousins and our entire offensive line.


Jeff Frodermann
Meier Tool & Engineering
Anoka, Minnesota

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[[Da...]]

They need to bring a bunch of Karens to show th O-line how to stand in front of somebody for more than 5 seconds! 🤣

[[Ne...]]

All this was helpful, you guys. I was seeing that caliper distance vs cartesian was matching more of the hard checks and had an internal battle of which to go with. I also like that you can use different alignments in caliper distance. I'd much rather use alternate alignments in characteristics instead of the individual features.

Go Browns! 🤬

[[Ri...]]

There isn't a lot of information in the Help regarding Cartesian, but there is for Perpendicular which is the same exact measurement.

The Basic training manual gives some insight though.

"Cartesian distance

A Cartesian distance calculates the distance between two points in one defined orientation (reference 1 and 2).
The orientation is specified with two features in the characteristic.
The first reference provides the spatial direction, and thus also the 'projection plane'; the second the direction for the distance."

Regarding a Perpendicular, per the Calypso Help.

"Feature 1 With Feature 1 in the definition template, define the point from which the perpendicular will be struck. You can select any feature as Feature 1.

Feature 2 With Feature 2 in the definition template, set the direction of the perpendicular. The perpendicular is vertical on feature 2. Therefore, feature 2 must be a spatially defined element.


I think the Cartesian Distance gets messy because it allows for Datums/References, so that you can use it to measure the distance between two 2d features. My assumption is that Cartesian Distance is looking at the features you place into the characteristic and if it is allowed to set a spatial direction then it will (think of the Can/May/Must Rule). So the reasoning you place the Plane as the first feature is to ensure that it is setting the direction.

I also have an assumption that things got muddied along the way with the directions of "Always place your Spatial Feature in Feature 2." This was most likely said in the case of a 2d feature being Feature 1, so yes it made sense to say always place your Spatial Feature in Feature 2. Kind of like I was always told to never have a +Z facing stylus on an XXT, but truth-be-told this was meant to never have a +Z facing stylus on an RDS with an XXT if using the CAA qualification.

Great topic. A lot of great points in here. I have my own personal feeling about using Caliper Distance, but they are my own, so I will keep them to myself.

Would be good to get some official word from Zeiss on this one.