DetailCurve.ByCurve deleting previous linework

[troy_troy]

I have a file that creates a series of curves between selected elements by using DetailCurve.ByCurve.
Every time I run the file, new curves are created, but those created in the previous run are deleted.
How do I prevent the deletion on each run?

Thanks.

Edit: I have found that by duplicating the lines in Revit (i.e. copying to the same place), I can run the file on other elements. Is there a way I can avoid this duplicating step?

[Chandrasekar_Rajaman]

Hi @troy_troy
My understanding is this:
If Dynamo gets curves by selecting objects from Revit, the ID is retained.
So when running the graph the next time, objects created before (with the same ID) are updated instead of being recreated. By this logic, duplicating will work as that means another set of objects with different IDs…

I had faced a similar issue when creating Views in Dynamo using levels from Revit.

Will also await the experts to confirm if my understanding is (in)correct.
Meanwhile, is it possible to create those base curves from Dynamo itself?

[troy_troy]

Thanks Chandrasekar. I will have a look into IDs and see if I can create a new one each time (or something).
I’m not sure I understand your question. Here is how I am generating the connecting lines for a planting plan. I am very new to Dynamo.

[Yna_Db]

Hi, here are two reference posts on this topic:

Dynamo Script does not remember Beams created

Here’s an interesting thought experiment. You can try to manually “internalize” the elements into your graph. Let’s say you create some beams on the initial run. You then proceed to record their IDs as strings like so: [image] and paste the result into a new code block. Once the design has been revised, you fire up your graph once more, convert those id strings to revit elements with archi-lab’s node and modify their location and size like so: [image] One of the biggest limitations is that…

Update Delete

This is a tough nut to crack. All newly created elements in Revit are linked to the appropriate creation node inside Dynamo. The logic is that if you delete the node, or change the input, it automatically deletes the elements inside Revit so that you don’t get duplicated elements one on top of each other. I don’t know of a solution, unfortunately but a temporary work-around would be the following: 1)Run your dynamo definition and create the elements. 2)Unhook the create walls node. That will …

[troy_troy]

Thanks Yna_Db,

Your post has certainly helped me understand the problem and limitations better.

[frank.hochban]

I know that this is an old topic, but what I found to work was to set the final wall element to ‘Is Output’ (right click menu). Then when run from the player it commits the addition and allows a different selection to be made.