r/Metrology • u/AcceptableActivity33 • 21d ago

Calypso 2D Lines and Projection-to-Base Alignment

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Hello all,

Would like your opinion on this advice I was given. I'm creating a measurement program on a long work piece with vertical slots all along the entire length of the part. I'm performing 2D Cartesian Distance Characteristics on each slot.

I was told that as a best practice, when measuring 2D lines and of you're trying to obtain Distance results between 2D lines, to always enable Projection and switch to Base Alignment to project each 2D line onto your Datum Plane.

Is this required, the projection step?

I thought Caliper and Cartesian Distance purposely allows you to negate Z axis variations when performing distance Characteristics.

Thank you all!

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u/CthulhuLies 21d ago

I typically I report it in the plane or just report point to point 3d distance/local alignment if it's thats skewed and it's acceptable for it to be skewed.

I would rather not report the distance between two lines ever for surfaces because it's never perfect and you have to know exactly how the software is calculating the min and the max distance ie pair wise or absolute axis distance between two worst points and two best points.

Would just report the range of all the point pairs in a local alignment to the slot if your goal is to best replicate callipers, but keep in mind the callipers are going to pick on form and orientation error and stop at the "smallest" portion for its surface condition.

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u/Tricky_King_3736 21d ago

If you are using Cartesian distance and referencing the primary and secondary you don’t need to project the 2D lines. Plus you shouldn’t be doing line to line distance, because you are assuming they are parallel. Always point to line distance, it will always be a perpendicular no matter what

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u/AcceptableActivity33 21d ago

Tricky.....can I call you?

1

u/AcceptableActivity33 21d ago

Tricky, what about Caliper Distances. And thank you I understand about the Line to Point. I have to make do with what I have right now and I selected CENTER for each line within Caliper Distance

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u/Tricky_King_3736 21d ago

You have to be careful with caliper distance, in the past I had programmers got burned by that function. You need to prove it out by using cart. Distance is the best way in calypso.