Family Instance Placement using Transform node

Hi, dear dynamo professionals.
I’m trying to copy family instances along two lines.
I want to place family instances at the coordinate system of those lines like below.

So I tried to use the “FamilyInstance.Transform” node like the “Geometry.Transform” node, but it fails.
No family instance is out and the results have the same element id as you can see below.
I think the same element id brought the wrong result, but I couldn’t fix it.
What’s wrong with the logic?

[Logic 1]

For your reference, I tried another logic (referenced by past dynamo forum articles) but it’s not give me the result that I require.
X Axis from the coordinate system is reversed as below.

[Logic 2]

[Logic 2 - Result]

I want to apply this placement logic to more lines, so I think logic 1 is more simple for me.
Does anyone have ideas about this problem?
Any ideas are welcome.

Thank you. :slightly_smiling_face:

Hi @myoh,

Just to be clear:
You say you wan to Copy the FamilyInstance along the lines or do you want to place new instances based on the FamilyInstance.

Copying means that the instance parameters are also the same (a different approach then placing new instances)

With Logic one, you are basically “Moving” your family to different coordinate systems. you have 1 familyInstance and 20 systems, so you will get 20 times you original family in the result, thus the identical ID behind all of them and the Original Family instance is the only family instance visible, because you just moved it from coordinate system to coordinate system.

Logic 2 is a better approach, because you use the data from 1 family instance to create others. This is almost the same as copying a family, the difference is that the new family do not have the same instance parameters as the source.

If the Families in approach 2 are not placed according your need, it is most likely because of the curves you made. Flipping a curve reverses the direction in which the families are placed. You can also flip the coordinate systems you use to create the families, this is mirror the families.

Thanks for detailed explanation @Joelmick !
I understand what you mean.
As you explain, placing new instances is just what I want. Then, it’s wrong with the logic one, right?

And I just want to place instances along the coordinate system of lines with no flipping curves :slightly_smiling_face:. It’s because, as I said before, I would apply this placing logic to much more numbers of the curves, so I cannot flip all of the curves that would be placed wrong direction.
I think it would be better to try flipping the coordinate systems of families!
Thanks, I’ll try.