Properties: Attachment Position vs. Base Position, etc.

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
edwilliams16
Veteran
Posts: 3112
Joined: Thu Sep 24, 2020 10:31 pm
Location: Hawaii
Contact:

Re: Properties: Attachment Position vs. Base Position, etc.

Post by edwilliams16 »

RussG wrote: Mon Jun 20, 2022 9:48 pm I see now that this is not always the case, that it's only true if the sketch is drawn on the XY Plane (if I understand things correctly).
Correct. Edit: Also, an unattached sketch defaults to its native XY-Plane.
edwilliams16 wrote: Mon Jun 20, 2022 6:02 pm They show the result of the effects of the Attachment (which rotates the sketch from its XY plane into the XZ Plane, and the effect of the Attachment offset - which being perpendicular to the sketch is -30 mm along the global negative z-axis.)
RussG wrote: I've read and re-read this part of your comments at least a dozen times. Would this be another way of saying what you did?: When the Attachment of my sketch which was drawn on the XY plane is translated by FreeCAD into the Global 3D space of the 3D View Window, the Z axis of my sketch translates to (aligns with) the Y axis of the Global space so that when I change the Z value of the sketch in the Position dialog it moves along the Y axis in the Global Space. Am I understanding this correctly?
Almost. The XZ_Plane is the global front view. In sketch coordinates x goes to the right, y is up the screen and z is towards you. Towards you is the global negative y -axis. So to move your sketch along the positive y-axis, you had to move it along the sketch negative z-axis. That's why your attachment offset was (0, 0, -30) not (0, 0, 30).

This is a quirk of the XZ-plane. For the XY and YZ planes, displacements along global z and global x are positive displacements along attachment-z.
Bance
Veteran
Posts: 4190
Joined: Wed Feb 11, 2015 3:00 pm
Location: London

Re: Properties: Attachment Position vs. Base Position, etc.

Post by Bance »

RussG wrote: Mon Jun 20, 2022 5:06 pm I have not yet found documentation that explains in terms I can understand how things work. I’ve seen <https://wiki.freecadweb.org/Placement> to which the most intelligent response I can make is “Huh, say what?”. Does anyone know of documentation that I might find helpful, something a mere mortal lacking a degree in computational quantum geo-spacial physics might be able to grasp?
Comments like this do little to encourage the volunteers that write, maintain and translate Freecad's Documentation. Please try to remember that this software is made by a handful of passionate people, it is not perfect nor should one expect it to be, given the scant resources used to provide it to us all.
RussG
Posts: 124
Joined: Wed Apr 27, 2022 11:27 pm

Re: Properties: Attachment Position vs. Base Position, etc.

Post by RussG »

Bance wrote: Tue Jun 21, 2022 6:21 am
RussG wrote: Mon Jun 20, 2022 5:06 pm I have not yet found documentation that explains in terms I can understand how things work. I’ve seen <https://wiki.freecadweb.org/Placement> to which the most intelligent response I can make is “Huh, say what?”. Does anyone know of documentation that I might find helpful, something a mere mortal lacking a degree in computational quantum geo-spacial physics might be able to grasp?
Comments like this do little to encourage the volunteers that write, maintain and translate Freecad's Documentation. Please try to remember that this software is made by a handful of passionate people, it is not perfect nor should one expect it to be, given the scant resources used to provide it to us all.
Well said and point taken. Thanks. These things are not lost on me but maybe it's fair to say a higher level of sensitivity on my behalf couldn't hurt.

Perhaps, however, my remark may also serve some positive good by illustrating a need for documentation written at a more simplified level.
Bance
Veteran
Posts: 4190
Joined: Wed Feb 11, 2015 3:00 pm
Location: London

Re: Properties: Attachment Position vs. Base Position, etc.

Post by Bance »

You are welcome to add to the documentation.....

Go here for permission to edit the wiki..... https://forum.freecadweb.org/viewtopic.php?f=21&t=6830

And here for some info.... https://forum.freecadweb.org/viewtopic. ... 1&start=30

The more the merrier.
edwilliams16
Veteran
Posts: 3112
Joined: Thu Sep 24, 2020 10:31 pm
Location: Hawaii
Contact:

Re: Properties: Attachment Position vs. Base Position, etc.

Post by edwilliams16 »

RussG wrote: Thu Jun 23, 2022 5:12 pm Perhaps, however, my remark may also serve some positive good by illustrating a need for documentation written at a more simplified level.
Have you looked at the Attachment Tutorial, in particular https://wiki.freecadweb.org/Basic_Attac ... Attachment
RussG
Posts: 124
Joined: Wed Apr 27, 2022 11:27 pm

Re: Properties: Attachment Position vs. Base Position, etc.

Post by RussG »

edwilliams16 wrote: Thu Jun 23, 2022 6:47 pm
RussG wrote: Thu Jun 23, 2022 5:12 pm Perhaps, however, my remark may also serve some positive good by illustrating a need for documentation written at a more simplified level.
Have you looked at the Attachment Tutorial, in particular https://wiki.freecadweb.org/Basic_Attac ... Attachment
No! That's one I hadn't seen. Thanks so much for the reference. I'll check it out.
Post Reply