Composite Wall Junctions: Patches etc.

[Anonymous]

I have been struggling for a number of years with composite wall junctions, and am very careful about setting skin priorities correctly. However, in many instances I’ve had to resort to using patches - mostly where 3 different walls form a T-junction.

For me, this a laborious solution, and almost outweighs the benefits of using composite walls. For example in a current project, although I have really only 5 different external wall types, and 3 different party wall types, I have no less than 59 different patches to cover (literally!) all the various configurations that occur at wall junctions. To be clear, all these patches are unique, and many occur several times in the project; so I have developed patches which are actually modules, in an attempt to reduce the editing load if a composite wall requires to be changed.

I have posted on this issue previously – but it appears that nobody suffers from the same problem, which made me think there might be an easier way round it.

Recently I have tried splitting each composite into 2 parts longitudinally, so that at a T-junction each part composite only forms an L-junction with its counterpart. Beyond the junction, the wall reverts to a full composite for ease of inserting openings. The difficulty has been in determining where to make the longitudinal split – not necessarily along the cavity, which you would think would be the most obvious location. Even then, I have found the odd stray line in the result, but these are minor and not too distracting. It’s still not a particularly elegant solution, because now for each wall type I have up to 3 composites all requiring to be managed, i.e. the original full wall plus the 2 component parts

Hopefully the snapshot illustrates what I mean.

I would be most interested to hear how others work round this problem. I can’t believe that I’m the only one!

[James B]

Hi Keith,

In the Wall Settings, you have a checkbox to enable skin priority, when this in enabled the priority slider above this acts as a sequence. the sequence determines which 2 walls meet first in a 3 way intersection that you have.
Therefore try to give a higher priority for Comp 1 and Comp 2, and the Comp 3 to have a lower number.
This might help.

James.

[Anonymous]

Hi James

I thought you'd solved it for me there, because I was unaware that the priority could be set individually for the whole wall.

However, I did what you suggested: maximum priority for comps 1 & 2, minimum for comp 3 - and it made no difference at all!

Could it be that the individual skin priorities within the composites over-ride the priority set for the wall?

[Barry Kelly]

As far as I was aware the wall priority setting only works when you turn off the enable skin settings.
But then it works on the wall as a whole and not the individual skins.
Although it will make the whole wall weaker or stronger than the individual skins of an intersecting wall if that wall has the enable skin options still on (does that make sense? - it's late on a Friday afternoon!).
Barry.

[Anonymous]

Ah - that's an improvement. Thanks Barry.

It seems counter-intuitive to turn off 'enable skin priorities' having taken so much care to set them up correctly. The junction is still not quite 'correct' in construction terms - but acceptable (a lot better than before).

I'll now have to see what happens when a wall that needs to be 'high priority' at one end, meets another 'high priority' wall at the other. Chop it in the middle, I suppose!

[JaredBanks]

These 2 posts from Onland.info will help you tremendously. You should be able to easily do those junctions without any patches.

This post pretty much writes the book on composite wall priorities.

http://www.onland.info/archives/2009/11/composite_wall_priorities.php

And this post on fixing wall corners with columns is just pure genius.

http://www.onland.info/archives/2010/07/fixing_wall_corners_with_columns.php

[Gerald D Lock]

archiben posted this very helpful piece on skin priorities and what numbers he assigns to various categories of skins

http://archicad-talk.graphisoft.com/viewtopic.php?p=82488
I've printed a formated version of the table and have it pinned next to my monitor for easy reference.

Looks like this aspect of ArchiCAD is about to get a whole lot smarter in v.17 as this video shows:
http://www.youtube.com/watch?v=fPlRm9nlpHg&feature=share&list=PLnXY6vLUwlWWa_BD5mX2l2YujV_CMtXFO