How to reference project wall widths?

[Roy_043]

Is there a way to reference project wall widths (e.g. load bearing=300, light weight partition=100, etc) in sketches? I realize I can define a 'multi material' with a thickness, but I don't think that can be used in dimensional constraints. In the attached example I have added 'dummy' constraints to 'Sketch' and referenced these in subsequent sketches. It works, but is sort of a strange workaround.

[chrisb]

Are there any differences in the two uploaded files?

[Roy_043]

I have fixed the attachments in my previous post. Thanks for pointing this out.

[paullee]

Hi, I am not sure if I understand you correctly

The Material object available help you to build multi-layer Arch Wall - search the wiki. With one single line / edge, you can build multi-layer wall, no need to draw a series of walls (nor make a series of sketches referencing to a 'master' sketch) - though I remember I tried to build multi-layer wall on a Sketch with multi-lines / edges or closed rectangle, there seems to be some problems. I have posted the 'findings' / 'lmitations' somewhere.

I have not tried to reference the multi-layer Materials in a Expression in sketch, but you may try if still desirable
I guess you want to 'setback' the edges / walls in Sketch003 / Wall002 right? I have similar attempt but want to do it 'automatically' but far from success...

On another issue, whilst I attempt to use sketch to draw architectural layout similarly, there are some other issues (posted in the forum), here is one I pick up again here:-

ArchWall Creation on Sketch Problem Again

1. Select a sketch - I pick 'Sketch001', which have some Link to External Edge to the 'Sketch'
2. ('Sketch' seems to be a 'master' sketch referenced by a few 'dependent' sketches in your file)
3. Mark it to Recompute, and Recompute the Document - for a numbers of times... until problem appears RANDOMLY
4. RANDOMLY, the 'Wall' built on this 'Sketch001' only return 1 wall ( 'vertical' grey one) rather than 2 walls (grey 'vertical' walls on screen) - the underlying sketch still return contain 2 edges from screen
5. I find a numbers of occasion like this and reported here - needs to recompute the underlying sketch (or the wall itself?) to randomly make all walls appears. Attempt to understand the code but haven't found which is 'culprit' or misunderstand the issue at all.
6. This time, find no error in Report view

'Wall' has 2 'vertical' walls Correctly

Screenshot from 2019-01-20 17-31-47.png (149.74 KiB) Viewed 1462 times

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'Wall' return 1 'vertical' wall InCorrectly, 'left' wall missing

Screenshot from 2019-01-20 17-32-05.png (150 KiB) Viewed 1462 times

Screenshot from 2019-01-20 18-06-08.png (176.25 KiB) Viewed 1462 times

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'Wall''s underlying 'Sketch001' still return 2 'vertical' edges Correctly, but 'left' wall missing in 'Wall'

Screenshot from 2019-01-20 17-49-18.png (148.73 KiB) Viewed 1462 times

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FC and OS Information
FreeCAD_0.18.15287.glibc2.17-x86_64.appimage on Fedora 27

[Roy_043]

Thank you for your answer Paullee. My question is indeed about referencing the width of materials in constraint expressions. Apart from maintaining a correct 'setback', this would also be useful to control the size of rooms that have critical dimensions. I don't think this is currently possible without the workaround I have used.

I realize that I may have gone a bit overboard with the multi-ply walls in the example. But very often a cavity wall does not have a fixed composition. Creating the insulation and the outer brickwork as a separate ply can be useful.

I have also noticed the 'random' disappearance of walls after recomputing. Saving to IFC shows similar issues: the walls are only partially exported. But maybe this is due to IFC limitations?

[Roy_043]

Alternative, and better, workaround: Use a spreadsheet for the project wall width and other project defaults.

[regis]

I am still so lost in to what you are trying to acheive. even after reading and opening your file.

[Roy_043]

Apart from getting to know FC, my goal here is to use wall widths and other critical dimensions in constraints.
Example scenario:
During the design process a different material is selected for the load bearing walls, their width changes, a staircase flanking such a wall has to move, the size of the room next to the stairs has to change as a result. And if that room becomes smaller than the building code allows the next room will have to be resized instead.

[regis]

Oh wow now I get it. I don't believe freecad current provides that kind of control. Thats very intuitive control. For now the only candidate I can think of is freecad spaces that can provide some intelligent information to a volume. But since it was not created for such there could be a need to entertain the idea of adding such feature so as to help it recognise various changes and adapt. But we are a long way from that currently I believe.

[yorik]

All numerical properties of objects can be referenced in other places that accept numerical expressions. So you can, for example in a sketch, place a dimension, and in the dimension edit box, write something like:

Code: Select all

myWall.Width

myWall being the name of the wall you want. Is that what you are trying to achieve?