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About Archicad's documenting tools, views, model filtering, layouts, publishing, etc.

Renovation tool issues with existing roof and new roof trimming.

Rob Hancox

The problem I have with the Renovation Tool is that on some “real world” tasks like putting in a pediment to an existing project becomes such a difficult aspect to model for a client.  Here’s an example.  In this project the house is getting a complete make-over with a considerable rear extension, significant room changes and layout changes to provide a better ‘flow’ through the house in addition to uprating the thermal U values and bringing a 1926 house with 3-4 major shoddy extensions into high spec reform.  This is a classic “Renovation” project.  Most of the ‘renovation’ tool features work ok, but there are one or two that completely fox me.  Perhaps I’m doing something wrong but I’ll try and explain the issue and hopefully someone can either correct the errors of my ways, or perhaps it is just a feature that isn’t yet resolved by Graphisoft.


So, here’s a snap of the existing house with an old window.  We want to insert a pediment above a new window with art stone inserts.  The window is no problem with the renovation tool.




So, step 1 is to ‘demolish’ the old window and ‘propose’ the new window type and opening, as Archicad ‘fills in’ the old window opening and creates a new opening for the new window element.

Next step is to place the ‘proposed’ pediment roof above the window.  So far, so good.



Then I need to cut the ‘existing’ roof to allow the ‘existing wall’ to meet and be cut by the new pediment.  Great stuff, all looks good. However……..



If I now select the “Existing” filter in the Renovation Tool my ‘existing’ roof has obviously been chopped along with the ‘new’ built up wall that is also cut by the future ‘proposed’ pediment.  So frustrating.




Is there a way around this or a fix in the offering from Graphisoft perhaps?


Many thanks in advance to anyone who responds.


AC25 UK • iMac 24" M1 • MacBook Pro 1.4GHz | 8 gb ram • OSX13 Ventura

Barry Kelly

Your new pediment roof is cutting the existing roof - which might be actually what happens in real life.

But unfortunately the cuts are not controlled by the renovation filters.

Even though it is a new pediment roof and will disappear when you show existing, it will still be cutting the old roof.

The only way I know to fix it is to 'demolish' the entire roof (or roof plane) and add a whole new one.



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Lee Hankins

The way I achieve this is to set the existing roof affected by the works to be pinned only to the exiting renovation filter. Then create a duplicate of the existing roof to appear on all other renovation filters you need to utilise. If you create the duplicate on the proposed over existing for example and cut the new roof in, then copy and paste this roof to all other filters as existing and pinned to each filter you can retain the existing as it is and then the existing but cut altered for the new section on all other filters. It is a bit of a pain and workaround but works for me. A great feature to add to Renovation Filters would be an option similar to show only on the current filter but to show on all except a specified filter. that would make the above solution much easier. Maybe you could also create a new opening in the existing roof shaped to the cut of the new roof? I haven't tried that though.

Lee Hankins
ArchiCAD 4.5 - Archicad 26UKI Apple Silicon 5003
macOS Ventura (13.4)

David Maudlin



What I do is fill in the cut roof area with a piece of roof that is set to Demo. This reflects what is actually happening: a part of the existing roof is being cut and demolished.


You should add a Signature to your Profile (click the Profile button near the top of this page) with your Archicad version and operating system (see mine for an example) for more accurate help in this forum.



David Maudlin / Architect

Digital Architecture

AC26 USA • iMac 27" 4.0GHz Quad-core i7 | 24 gb ram • MacBook Pro 2.8GHz | 16 gb ram • OSX10.15.7


@Lee Hankins Except we are still waiting for the Opening Tool to work with roofs... one day... 😉


@Rob Hancox Option 3... Cut back the existing roof shape and and add in a new piece of roof matching the existing and mark it for Demolition.

Apple iMac macOS Ventura / AC26UKI (most recent builds)

Ah, now I've heard of this feature but not yet tried it. So I'll have a review of how to use this and feed back.

With regards to cutting and preparing a section of the existing roof to be marked as demolition is how I deal with differing walls that are cut by a door or window and need reshaping in any way.  Thanks for your idea however, I've never used the pinned option.

AC25 UK • iMac 24" M1 • MacBook Pro 1.4GHz | 8 gb ram • OSX13 Ventura

Option 3 - I've used this method before.  It does simulate what you're doing in real life I suppose, so it probably warrants more thought.

AC25 UK • iMac 24" M1 • MacBook Pro 1.4GHz | 8 gb ram • OSX13 Ventura

Rob Hancox

Have updated my profile.. Thanks for your advice. 👍

AC25 UK • iMac 24" M1 • MacBook Pro 1.4GHz | 8 gb ram • OSX13 Ventura

Many thanks for your “pinned” advice.  This solution works well, as the ‘real world’ method of cutting a triangular section out and marking up for demolition created line artefacts that then required further faffing to remove.


The “pinned’ to Existing Renovation layer and copying the roof elements to the Proposed Renovation layer worked very well.  Just wish Graphisoft could include this in future versions.







Thanks again.

AC25 UK • iMac 24" M1 • MacBook Pro 1.4GHz | 8 gb ram • OSX13 Ventura

Glad it worked for you. What I tend to do also is make a note in the inbuilt Project Notes for the file to remind me what I did or for someone else if they work on the project. If you end up pinning lots of elements to specific filters it can get complicated. 

Lee Hankins
ArchiCAD 4.5 - Archicad 26UKI Apple Silicon 5003
macOS Ventura (13.4)

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