Datum point highlight colours and datum point creation.

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Mal_Smith
Posts: 7
Joined: Tue May 02, 2023 8:17 am

Datum point highlight colours and datum point creation.

Post by Mal_Smith »

I'm fairly new to FreeCAD, so I may be missing something. I'm not sure if the following are bugs or limitations:

When I pre-select or select a datum line or a datum plane I get the highlight colours. When pre-selecting or selecting a datum point, I don't get the highlight colours. Is this a bug?

A second issue I have is that I don't seem to be able to place a datum point at the intersection of a datum line and a datum plane, or at the intersection of three datum planes. I get an error message about infinite entities, which the datum lines and planes are of course, but mathematically there is only a single solution, so I don't see why this would be a problem.

A third issue, I don't seem to be able to create a datum plane parallel to another plane or face and passing through a datum point or vertex. Is this possible to do?
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mfro
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Re: Datum point highlight colours and datum point creation.

Post by mfro »

Mal_Smith wrote: Wed May 10, 2023 2:08 pm When I pre-select or select a datum line or a datum plane I get the highlight colours. When pre-selecting or selecting a datum point, I don't get the highlight colours. Is this a bug?
Probably. Maybe worth a github issue. I personally just hit the spacebar once and again which makes the selected object vanish and reappear, DatumPoints are difficult to identify anyway.
Mal_Smith wrote: Wed May 10, 2023 2:08 pm A second issue I have is that I don't seem to be able to place a datum point at the intersection of a datum line and a datum plane, or at the intersection of three datum planes. I get an error message about infinite entities, which the datum lines and planes are of course, but mathematically there is only a single solution, so I don't see why this would be a problem.
That should work. Select the DatumPlane, select the DatumLine in the second slot of the Attachment parameters. That might give you indeed the 'infinite' warning which should go away when you select 'Proximity point' as Attachment mode. Unfortunately, the same doesn't work with tree DatumPlanes.
Mal_Smith wrote: Wed May 10, 2023 2:08 pm A third issue, I don't seem to be able to create a datum plane parallel to another plane or face and passing through a datum point or vertex. Is this possible to do?
Should work as well - in two steps. Attach one Plane "Plane face" onto the other, then modify the Attachment to contain the point only. In that case, undefined Attachment vectors just retain their previous values.
Cheers,
Markus
chrisb
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Re: Datum point highlight colours and datum point creation.

Post by chrisb »

Mal_Smith wrote: Wed May 10, 2023 2:08 pm A second issue I have is that I don't seem to be able to place a datum point at the intersection of a datum line and a datum plane,
No problem here:
Snip macro screenshot-f656a7.png
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Attachments
DatumPointLinePlane.FCStd
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chrisb
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Re: Datum point highlight colours and datum point creation.

Post by chrisb »

Mal_Smith wrote: Wed May 10, 2023 2:08 pm I don't seem to be able to create a datum plane parallel to another plane or face and passing through a datum point or vertex.
It is a bit funny, but somehow understandable (it is as tangent as possible while going through the point): use the AttachmentMode "Tangent to surface".
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Snip macro screenshot-d8dd09.png (2.76 KiB) Viewed 852 times
Attachments
DatumPointPlanePlane.FCStd
(5.4 KiB) Downloaded 29 times
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Mal_Smith
Posts: 7
Joined: Tue May 02, 2023 8:17 am

Re: Datum point highlight colours and datum point creation.

Post by Mal_Smith »

Thanks for the replies. As long as I know it's possible, I will figure it out. I will report the highlighting issue.
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