Modify Model Lines of an Existing Floor Slab

[avpBS7DE]

Dear Revit API,

I need to change the borders of a Floor Slab automatically. The ID of the element should not change (I can't delete / recreate another Floor). I tried to capture the underlying ModelCurves and change them but I get errors. I wonder, is it possible what I try to do and what is the best way ?

Thank you

[Sean_Page]

Unfortunately I do not believe this is possible at this time. You can create penetrations or openings in the floor, but not modify the actual boundary unless you recreate as you mentioned.

[RPTHOMAS108]

You can make some basic changes to the underlying model lines within the sketch. I've recently used ElementTransformUtils.MoveElement successfully to offset a line. Probably the key is to ensure that the sketch remains joined up (when you move a line in the UI it drags the other joined lines with it). It may be possible to directly alter the geometry curve of a model line if you've ensured all the lines you are changing still join. I've not tested this and it would depend on when the check for a joined up sketch is undertaken (ideally upon transaction commit). You can only change one curve at a time and in the UI this is dealt with via a sketching context but in the API you just have model line elements.

So when you commit changes does it review the overall picture of the sketch or the changes of each model line in turn. If the commit looks at each model line change in turn (in relation to it's existing neighbours) then there will be a point where the new line information doesn't join with the existing line information (not yet updated). 

[so-chong · Accepted solution]

Hi,

Did you find this blog post by Joe Ye?

https://adndevblog.typepad.com/aec/2013/10/change-the-boundary-of-floorsslabs.html 

Though this post is a bit outdated it still works in newer version of Revit.
Using the Revit Lookup tool to examine the Id of the element, Id remains the same after executing the code.

I hope you'll find it useful.

[avpBS7DE]

Thanks So-Chong, that seem like a great post. 

I hadh done exactly that and reading the post encouraged me to look deeper into the problem again. 

As long as the model lines form a close loop again, then you can modify the floor. My mistake was something that some line wasn't connecting properly.