I've got a real problem with the DEMON changing the number of hits in a scan, programmed offline vs. being ran online. My real issue is pulling hits from these scans for intersect points on short surfaces. It there a way to lock this up so the hits are what I programmed it to or do I need to get my program changed. Picture a small piece of pie (each side approximately 7mm long) with chamfers on the 3 corners at 0.65mm to 0.7mm. Running the program offline produced exactly what I the CAD/print shows and I've been beating my head against the wall (run this through Inspect so I saw no data) tryin to get this figured out.
I see the number of points different you have posted elsewhere, and that seems extreme to me.
However, What Neil says is true in mCosmos and Calypso as well, as I have those and PcDmis here scanning in all three. If you want two hits per mm (.04") and your part has a perimeter that is 2 mm longer than the model, that would be an extra 4 hits.
With the delta you describe, and my best guess about actual size, I'm thinking you go from 23mm perimeter to 23.2-ish (based on the stated profile error if the part is bigger, 22.8-ish if smaller), so at 2/mm that would not even be one hit. I think you said something like 12-15 hits different.
What Neil describes, based on what I can guess, is not what you are experiencing. That doesn't make Neil wrong in what he said, though, as he doesn't know how many hits are missing, nor did he know your profile deviation.
In all three softwares, I can extract features so the points used are dynamic based on the actual scan (what Neil is suggesting), or I pump the density so that a few extra or missing hits don't wreck me on discreet point selection for constructions (what you appear to be doing).
I would never be able to live with 15 hits missing, though.
I can say, in Calypso, once, I had to re-select points after running a part online after programming offline because they were WAY off. Once. It is a machine we bought for a product family of 8 parts. Seven parts went from offline to online flawlessly. One part I had what you are having.
I didn't bother with the why, I changed my point selection and then it has worked ever since. Some artefact that the software saw in the model that isn't real, maybe, a seam that the software followed into the solid and back out that skewed my point count? I have no idea.
My point there is, I changed my point selection and it worked ever since. Can you do that?
If you run 10 parts, do they all have the same point count and distribution that this first part had? Maybe a single fix and you are good to go forever?
From the way mCosmos makes scan sections, I can visually see that the software follows seems into the model sometimes, and there is a method to trim that crap out. Maybe that is happening to you here, or something similar behind the scenes, and a one time adjustment will get you on track.
I see the number of points different you have posted elsewhere, and that seems extreme to me.
However, What Neil says is true in mCosmos and Calypso as well, as I have those and PcDmis here scanning in all three. If you want two hits per mm (.04") and your part has a perimeter that is 2 mm longer than the model, that would be an extra 4 hits.
With the delta you describe, and my best guess about actual size, I'm thinking you go from 23mm perimeter to 23.2-ish (based on the stated profile error if the part is bigger, 22.8-ish if smaller), so at 2/mm that would not even be one hit. I think you said something like 12-15 hits different.
What Neil describes, based on what I can guess, is not what you are experiencing. That doesn't make Neil wrong in what he said, though, as he doesn't know how many hits are missing, nor did he know your profile deviation.
In all three softwares, I can extract features so the points used are dynamic based on the actual scan (what Neil is suggesting), or I pump the density so that a few extra or missing hits don't wreck me on discreet point selection for constructions (what you appear to be doing).
I would never be able to live with 15 hits missing, though.
I can say, in Calypso, once, I had to re-select points after running a part online after programming offline because they were WAY off. Once. It is a machine we bought for a product family of 8 parts. Seven parts went from offline to online flawlessly. One part I had what you are having.
I didn't bother with the why, I changed my point selection and then it has worked ever since. Some artefact that the software saw in the model that isn't real, maybe, a seam that the software followed into the solid and back out that skewed my point count? I have no idea.
My point there is, I changed my point selection and it worked ever since. Can you do that?
If you run 10 parts, do they all have the same point count and distribution that this first part had? Maybe a single fix and you are good to go forever?
From the way mCosmos makes scan sections, I can visually see that the software follows seems into the model sometimes, and there is a method to trim that crap out. Maybe that is happening to you here, or something similar behind the scenes, and a one time adjustment will get you on track.
