Arch Space - Boundaries Behaviour

[paullee]

Hi, I read Yorik's blog and find there have been terrfic added features to Arch Space !

I have some test and find definition by boundaries surfaces is awesome and easy to use!

After some more test, there is some behaviour which may seem not as intended?

• Create a series of wall, some subtraction volume, create Arch Space and select 2 surface

• It is expected the only 2 selected wall surfaces 'define' the volume ...

• Firstly it seem, though one of the selected wall face is subtracted by a cube, the resulted Arch Space seem add back the subtracted bit (a cube subtracted at the end of wall)

• Then, it seem the whole series of wall are included in consideration rather than on the 2 selected wall surfaces

• Adding another surface as shown have the whole 'imagery infinitely extended' volume behind this wall subtracted

• Adding another surface have similar effect

• So, trying to created a zig-zag Arch Space by selecting the defined wall boundaries seem not sucessful

Any idea? Thanks!

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OS: Windows 7
Word size of OS: 32-bit
Word size of FreeCAD: 32-bit
Version: 0.17.11827 (Git)
Build type: Release
Branch: master
Hash: ca4488f4387f761df47322038585b23cb5a1bd73
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.0.0
Locale: Chinese/HongKong (zh_HK)

[yorik]

Yes there are many situations where this "boundary" system will fail. Then you'll have to fall back to more traditional ways (modelling the space volume yourself by other means)

Basically it works like this:

1) if the space has no base object, a volume is built by adding together all the bounding boxes of the selected boundary faces.
2) from each boundary face, a subtractable volume is built, then subtracted from the base volume.

That indeed will disconsider "cuts" that you have in the boundary faces.

[paullee]

Yes, I forget right after reading about the bounding box!

The example creating an Arch Space shown with 3 wall cut away an bounding box is somehow not quite 'intuitive' in understanding for me. I am not sure what others think.

Just a quick idea, see screenshot

• the arch space is the common of any 2 projection volume defined by the selected surface...

EDIT - in fact... the volumes so defined so be 'projected' 90 degree at a plane / line's open end; but extended 180 degree indefinitely to the end 'connected' to adjacent plane / end

• so if 2 plane >= 180 degree will have no volume( or in this scenario the bounding box be the volume...)

Hope it helps.

EDIT

• For the 1st example, the last bit of wall to the lower left corner (/ the strip of its projection) will not intersect any other wall projection, it will excludes this strip. For the strip to be included and perceived as bounded by the opposite wall, it seem the Bounding Box of all these walls could be included - any wall project common with this Bounding Box should be included then.

• This is about perception - think about something like Barcelona Pavilion, external space of Ronchamp etc

Results anticipated ('simulated' by Part Common of Solid, Extrusion of Facebinder etc.)

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EDIT - updated

Test_ Arch Space _ Problem_2 .FCStd

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[paullee]

Yes there are many situations where this "boundary" system will fail. Then you'll have to fall back to more traditional ways (modelling the space volume yourself by other means)

Basically it works like this:

1) if the space has no base object, a volume is built by adding together all the bounding boxes of the selected boundary faces.
2) from each boundary face, a subtractable volume is built, then subtracted from the base volume.

That indeed will disconsider "cuts" that you have in the boundary faces.

A side issue to note - if the walls are in 1 sketch as i do, it is vulnerable to topological naming problem. The selected surfaces change after a touch in the sketch and become chaotic

EDIT - In addition, containing a numbers of walls in 1 sketch prevent from selecting individual walls to be contained as base object. My workflow has this limitation.

[paullee]

There had been other discussion about creation of ArchSpace by selecting ArchWall faces would not be possible if the Space / Region / Room has 'convex' situation.

Experiment in progress below, no problem with the said situation, and hope ArchSpace needs not be separately created duplicating all the efforts of creating ArchWall then

[Feature] Drawing Walls = Drawing Rooms Automatically
- https://forum.freecadweb.org/viewtopic ... &p=497584