Renovation and alteration work

[Paul King]

Even as a long time ArchiCAD user, I have mostly given up on BIM for most alteration work - it is logistically just too hard with the workarounds required to document new vs. existing work. So much faster just to draw in 2D sadly.
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What would help is the ability for new & existing walls, windows & doors to coexist more intelligently - automatically showing in elevation for example, dotted lines where a window has been removed, and shading in new / patched areas (same for plans & sections & 3D)

If ArchiCAD could interrogate the differences between two models occupying the same space, and establish the differences between them & graphically present those differences intelligently (with much user customisation) in all views, ArchiCAD would make so much more sense for small alteration projects.

Currently so much non-intuitive trial & error & manual fudging is required to maintain a BIM verion of both new & existing buildings, and then having to manually doctor most views to show the changes (and every change to the changes) that there is really very little pay-off in using BIM on the tiny fees earned.


Probably the majority of Architects out there make a meagre living doing exactly these projects, so Graphisoft would have a huge hit on it's hands if it could deliver the first BIM package that actually paid off for this kind of work!

[KeesW]

It is now morning and I am awake. The book I referred to is Framework and I have found it extremely useful. The technique is to create a locked 2D version of the existing floor plan, on a different layer, using dashed lines, under the normal existing model plan. When existing walls are removed, the dashed lines are revealed, thus creating a demolition plan.