I’ve got a graph that takes all the MLEADERs in the drawing, gets the arrow coordinates, and writes to a CSV the MLEADER contents, the layer’s description, and the northing & easting. When I made the graph on a test file with about 100 or so MLEADERs it worked fine. But after spending a week adding 1100+ MLEADERs to a drawing the graph isn’t working properly. Specifically, it’s failing on the Multileader.ArrowheadLocations node for a few of the MLEADERs, but not all. It throws an error of
Multileader.get_ArrowheadLocations operation failed.
eInvalidIndex
on some of the MLEADERs and returns null, which throws off the rest of the graph. I’ve already got the list of MLEADERs split if the number of MLEADERs is one versus more. Both Multileader.ArrowheadLocations nodes have the same few errors.
Here’s an example where there’s obviously a Multileader object being passed to the ArrowheadLocations node, but it returns null.
Why are some of these MLEADER coordinates not working? I’m using C3D 2026.2, btw.
Hi @Cadguru42,
Any chance you could share the DWG? Feel free to send a DM if you prefer.
I sent a message with a drawing earlier. I hope it’s not related to the issue of the first leader being removed after a second (or more) leader were added. Tracking those down will be a pain.
I just tested and the Multileader.ArrowheadLocations node will return null if the leader has had an arrow added and then the first arrow is removed.
You could use the below set up to identify those arrows:
Thanks for sharing your DWG. I was able to debug and find the issue. We’ll get this logged and fixed in an upcoming release.
In the meantime, here is a workaround that you can use to get the arrowhead locations. Give it a try and let me know if you have any issues.
MLeader.ArrowheadLocations.dyn (6.8 KB)
Thanks again for reporting!
Thanks for confirming it’s a defect. What does that Python node output? I don’t know Python. It looks like it outputs Dynamo Points of whatever MLEADERs are passed to it. Would I be able to substitute the Multileader.ArrowheadLeaders node with this Python node?
Yes. It can be a direct replacement for the Multileader.ArrowheadLocations node.
