[Discussion] A different approach to Arch modelling (Arch Assembly?)

[carlopav]

Users might think that this is what this appearance of a join actually represents - a physical join made by cutting both ends at 45 deg angle.
While in reality, this is just a UI appearance of a model that doesn't define how the walls are joined in reality.

I just ended a project where prefab walls were joined like this in the reality but I agree that was not something common.

So, to truthfully represent the model in UI, when unselected, this join should appear to be seamless.

Sure. My idea was to perform a boolean fusion of all the walls when outputting the svg to techdraw, but for every other use keeping them separated. I have no Idea how complicated it is to suppress the representation of that seam, since at the moment the viewprovider code was provided by @realthunder and it does simply represent the Shape in coin. I dont really now where to put our hands, and if that's something that worts the effort.

If we want to model joins, there should be multiple types:

You can easily produce all those join types by hand, if you show all wall hidden properties you will realize that you can control pretty much everything .

And it gets complex with multimaterials:

This is not just complex... it's COMPLICATED indeed! I don't know if those softwares just produce a 2d joining or modify a 3d solid too... I guess the first.
Anyway what I was thinking is to just cut 45 degrees all layers and do not bother at all about if those layers would join or not. And provide a command to convert every layer in a wall subobject, so if the user really needs to make every layer match, he can do it by hand, keeping the wall global functions like window hosting and subtractions.
But i'd really like to have suggestions on this topic. Just remember FreeCAD is mainly a mechanical cad, so I do not think it is generally a good idea to take a too different path.

[paullee]

If we want to model joins, there should be multiple types:

assets_-LHDKT83ix-GRhZ_zoix_-LHDKXHh_b0ZtmY-hVUB_-LHDK_ysqOHkevAqKVVC_RevitJoinType.png

And it gets complex with multimaterials:
6a00e553e1689788330154362e3ae1970c-800wi.png

Thanks, what is difference between Butt, Miter, Allow Join ?

[vanuan]

Thanks, what is difference between Butt, Miter, Allow Join ?

So, there should probably 2 modes: allow joins and disallow joins.

Disallow joins is probably not very useful, but it's clear that this models walls as intersecting solids.

For allow joins, there are 3 types: butt, miter and square off

By default, allow join has butter, so those are identical. For 90 degree joins, butt and square off are identical.

The difference between miter and butt is probably obvious from pictures (45 degree vs flat surfaces)

The terminology appears to stem from woodworking:

https://en.wikipedia.org/wiki/Butt_joint

[carlopav]

I generally do not know how much we should concentrate on how much geometry have to match reality:
In the end we always dial with representations of reality, and so this representation is always subject to a certain degree of semplification. This certain degree of semplification is not necessary evil, it is how we gain control over the reality and deal with its complexity, so we just have to choose which informations, in which phase of the design process are useful, and which we can discard in favour of a global effective workflow.
At least that's what I think.

[carlopav]

ping

Didnt' get the invitation in hangours, we can just use:
https://meet.jit.si/openbim

it is widely used in https://community.osarch.org/ and we also used it with yorik.
tell me a time when it's ok for you

[vanuan]

I generally do not know how much we should concentrate on how much geometry have to match reality

At the very least, you should be able to produce standardized representations of reality. Those are IFC models and 2D drawings.

To produce 2D drawings, FreeCAD Arch currently uses section plane cuts. It means that wall joins would look exactly like the 3D geometry. If 3D geometry uses miter joins, it would be represented as miter joins on 2D. I don't think miter joins is a good default option. Especially if it's the only option.

Let's use this Revit tutorial as a reference: https://www.lynda.com/Revit-Architectur ... 746-4.html
and see what are the equivalent steps in FreeCAD BIM. The tutorial sections we're interested in are "Drawing an interior wall" and "Modifying a wall join".

Here's a more detailed tutorial: https://caddetailsblog.com/post/8-tips- ... wall-joins
So Revit has multiple ways to model wall joins, as well as ways to hide/display boundaries between joined walls.

I believe, at the very least, FreeCAD should target Revit features that were provided in 2014 if not earlier: https://www.youtube.com/watch?v=rXG02V_TEUs

[carlopav]

I do really think Revit way it's not good. Can you imagine how many times it fails to guess what you want to achieve?
We have to find a better way. And we have to do it in a "freecad style" if we want to do it with freecad!

[paullee]

That looks complicated Any better idea ?

[Bojan_Bekic]

That looks complicated Any better idea ?

I think it would be best first to finish some basic features:

- Walls connecting without a visible line, Г and T connections.
- Having an option to leave that line visible if needed (connection of walls with different materials without relying on arch fuse)
- Support for materials so one could output drawings at least with color, if not hatching, and doing a simple bill of quantities would be possible
- Fixing the section view output
- Adding more options for windows

That way we could already have a thing that works. We could actually produce drawings And only then tackle the complicated world of multilayered walls.

What do you think?

[carlopav]

The point is that some of this is not basic at all from my point of view

- Walls connecting without a visible line, Г and T connections.
- Having an option to leave that line visible if needed (connection of walls with different materials without relying on arch fuse)

No idea how to do that and not my priority: if the line correctly disappears in the svg output of techdraw, I can live with that line in the 3d view.

- Support for materials so one could output drawings at least with color, if not hatching, and doing a simple bill of quantities would be possible
- Fixing the section view output

Yes, that's something high priority I believe.

- Adding more options for windows

Mind that you can design your custom windows through PartDesign and embed them into the opening tool. You can even embed a current window into the opening! (extending the window presets is also easy, if you can write some simple python).

That way we could already have a thing that works. We could actually produce drawings And only then tackle the complicated world of multilayered walls.

Yes, this should be the short therm goal to attract more people to Arch and BIM workbenches.