Constructing features out of Freeform Scan

[RanDawgg]

Is there a way to construct features out of specific sections of a freeform scan? Say I wanted points 26-30 constructed into a circle. I think I could do it by assigning variables to the specific hitpoints, but I'm hoping there is an easier way.

[Sora5]

Click construct circle and select the freeform scan. Create it with your specified parameters to get the feature constructed in the Edit menu. It might or might not pop out a math error. In your constructed circle feature, find the line CONSTR/CIRCLE,BF,2D,SCN1,, and add the .hit extension to the name so it has SCN1.HIT[26..30].

[SingularitY]

You can select areas of the CAD model instead of the points and it will only extract the points in between the areas selected. You can remove outliers if you choose to also. No need to know which points are needed exactly.

[newaircrafthomebuilder]

SingularitY: I didn't know you could do this I need to go test this out I used to extract individual scan points then create features from those points. Could you give details I'm not getting it to work out on trying to construct a cylinder from freeform scans that are scanning 3 surfaces.

[RanDawgg]

How does that work, Singularity? Do you select the scan in the construction menu, and then select the areas on the CAD model?

[RanDawgg]

prof-Xact.PNG

Does anyone have any ideas on why the second line of my profile is so far off? Struggling to find where I screwed up.

[RIDER]

Turn on the Max and Min under the F10 tab to better understand profile data.
What is SCN1? What is the relationship to A? Need more info please.

[Mike Ruff]

Based off how it's shifting the DRF for the lower section, my guess is that is calculating incorrectly. PC-DMIS likes to corrupt Xact Measure dimensions sometimes. If you haven't already, try deleting and recreating the dimension and see if that helps

[Mike Ruff]

Also, your dimension shows MMB on datum C for the upper segment, but your report does not. This tells me that the dimension you posted did not generate the report you posted

[sealevel]

Maybe re-create 'A' since it looks very jaspered up, and feed Xact the MMC size for 'C' (be it boss or hole)
Also am curious what release you're using? Some releases are more 'Xact' then others....

[RanDawgg]

I've recreated A, the feature in question, and the characteristic, still get a dev > 1. I've never fed Xact anything, do I literally just put the MMC size of Datum C in the control frame?

Any GD&T experts have an opinion on that second profile characteristic? Datum A is +Z plane, and the features in question are radially perpendicular to it.

Using 2019 R2

[AndersI]

"Radially perpendicular"? What kind of feature(s)?

[RanDawgg]

Please forgive me for this atrocity of a drawing. Sorry for my wording, it's just a mixture of radial and flat features. It is a very thin part, just kind of wondering why the 2nd profile would even be necessary.blah.png

[Sora5]

As Mike said, your report is not matching the FCF you showed us, so there's some disconnect there that is confusing the issue. The shift, especially the 270 rotation shown on the second segment is a major red flag. Something is going wrong with how you're measuring the feature or your method of creating the Xact FCF. Try to dimension them in two separate profile dimensions. It's the same when your profile isn't called out as a composite.

The second segment is there to control the form of your profile to a tighter tolerance. To make sure all your curves are looking good ^^

[RanDawgg]

Everything appears to work fine when I dimension the second line separately. Still looks terrible when I dimension them together.

They aren't composite, so I guess I'm good to go! Still want to figure what's going on.

[sealevel]

In Xact Meas, check the custom DRF in the lower-center of the Xact image you posted. This will show you the 6 degrees of freedom how Xact sees them to be (x,y,z,u,v,w)
As for the MMC, yeah, you need to tell it what MMC is. For xample it C is a outside dia of nominal Ø.250 ± .005, you'd enter .255 in the grayed size area of :
[Ø<size>] to look like [Ø.255]

[AndersI]

You only need to enter the <size> when it should be different than what's stated by theo and tolerance. This should be explicit on the print...

[sealevel]

Thx for that AndersI. I suppose I was always putting MMC value in Xact before running the prg. Never really tried to just run w/ theo & tol.