Renovation and alteration work

I agree essentially however I do not think that all of this should be sorted based on D/W settings. For example you cannot place let's say an opening-to-be-demolished in the same wall next to a new opening because this action could have fairly complicated consequences in the calculations module so in other words it would be a very complex problem to code (considering that AC's complexity is growing with each release).
A possible solution could be a new setting for layers where we could turn all objects placed on a particular layer to one pen/line type appearance in 2D and 3D (a sort of BYLAYER settings in ACAD). This would require keeping all elements-to-be-demolished as a separate structure on separate layers. It would be ok with me as we could always have a referencing point to the original structure without interfering with the actual model.

Samovar wrote:
There's a good article on strategies to manage remodelling on AECbytes by Eric Bobrow:

http://www.aecbytes.com/tipsandtricks/2008/issue26-archicad.html

Yes - good article. The downside with all these approaches though is the need to manually manage the logistics required to keep the three views looking right as things change - splitting walls etc to adjust what shows as what in new & existing & demo plans - and every time you need to update as built or new models, previously split walls and other elements need to be manually replaced with splits in different locations - wrecking dimension strings, windows, accessory wall cladding elements etc. Tedious.

Often an as-built model is not completed until the project is well advanced - and to have to go back & manually fudge things to accommodate new vs existing changes in the new model at this late stage is painful.

With a smart difference engine, ArchiCAD should be able to work out what it needs to show as demolished vs new vs unchanged in any view, leaving user to focus on the project itself, not the logistics & reworkng needed to trick the software into keeping up

Paul,

I have used Eric's method for a couple of residential renovations recently and have not found it at all difficult or problematic. I would suggest you give the hot-linked method a try. Your layers stay simple. The existing plan stays current, even late in a project, and there is not need to worry about existing, demo, or new layering.

I only notice two slight difficulties. First there is the need to update your hot-linked file (this is easier if you can afford to link a plan rather than module as there is no need to re-export an updated module first), and updating the 2D demo plan can be a little annoying.

Still compared to the days spent doing this with layers in 2D, things are much better.

Of course it would be better still if elements of a model could be marked as demo and change appropriately.

What about internal & external elevations? - where removed or relocated windows need to display dotted accordingly, patched walls and new elements display hatched accordingly etc. - currently I have to laboriously fudge this with 2D dotted lines & fills & fake mini wall elements etc , and re-fudge it every time new or existing model elements change.

I also struggle with things like showing high level windows above doors or windows in the same place lower down , and distinguishing in plan between what is removed above (dotted) vs what stays above (also dotted, but different line style needed)- and for this to also work properly in elevation.
With the wall display options currently available there is no obvious way to apply the multiple lifestyles needed to distinguish between windows kept & removed overhead in plan without upsetting the linestyles displaying in elevations of at least some of those windows.

Creating a separate story/ plan for overhead windows is often not really a good option when there is only one or 2 of them, especially when some windows on the lower story extend higher than stacked/overhead windows placed on higher story - and it gets truly nasty when some of these do need to show as moved or removed consistently in plans & elevations!, and for all of this to work with wall cladding accessories that are very sensitive to any fudging affecting walls they are associated with.

Paul,

In the few projects, I have used this method with, I have not had to deal with issues such as high overhead windows or showing demo windows in elevation. However, as I typically would have a demo plan and a revised plan in my work flow, I doubt this would be an issue for me. However, it sounds as though you are displaying demolition information along side existing and new information...hmmm messy no matter what.

For showing elements in elevation, I would probably generate a patch and adjust the patch display as appropriate to reflect the demolition work. So no real help there as it sounds as though you are doing something similar now.

Renovations are always a pain to document no matter the tool used.

Erich wrote:
Paul,

... it sounds as though you are displaying demolition information along side existing and new information...hmmm messy no matter what.

For showing elements in elevation, I would probably generate a patch and adjust the patch display as appropriate to reflect the demolition work. So no real help there as it sounds as though you are doing something similar now.

Renovations are always a pain to document no matter the tool used.

Hi - I would normally show demo info (dotted) alongside existing & new only in cases where the demolition creates a need for making good of existing elements that remain - such as patching a wall where a window used to be
- i.e. only to the extent that is required to show the extent of new work involved in elevation.
The same removed window however needs to display with normal lines on as built plan, with dotted lines and/or hatched in a demolition plan, and as a differently hatched segment/patch of wall in a new plan, and in elevations - and all without messing up or being obscured by wall cladding accessories on new model

Graphisoft, if we can put a man on the moon, surely we can make these tasks do-able & update-able as an automated process , with user defined graphic parameters.?!

Essential!
I agree with Paul - AC does not make it easy to handle alterations and additions. Revit seems to manage this very well by remembering what it is was like before changes were made and automatically giving demolished elements into dotted lines, etc.

We use the system outlined in the NZ Archicad book (forgotten the name for now but written by Rattenbury I think). I can give you some details about this if you want.

We find Archicad not very friendly for using the same file for different stages of the architects's service and create separate files for each stage (including one for existing and demolition works).