Hi all
I’m trying to create a Place Family on Grid Intersection with Model Line.
The Family placement is on the intersections but not parallel to the grid line.
Is there a way to make it so? What nodes should I use?
Thanks!
You can always rotate them after creation. Get the angle between certain axis and the grid or something. Btw I really like your id, legend. 
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Thanks! haha 
I’m currently rotating them manually. Looking for alternative
Curve.ParameterAtPoint then Curve.TangentAtParameter for the Grid
Against Family Instance.Facing Orientation?
Not sure, but it doesn’t align as I want it to be
I hope this is helpful. To be honest, it surprises me that FamilyInstance.SetRoation node does not have an axis input. And you could look into familyinstnace.FacingOrientation and HandOrientation as well which also depend on how the family was modeled, might need some trial and error.
rotate_fam_instance_grid_intersection.dyn (23.1 KB)
Out of curiousity.
How do you determine which Grid you (not) want
your Element parallel too
(given just the intersection of the two Grids)?
Or did is miss something?
This works for Grid intersections
If I want it to work for intersections between Grid and Model Line (Curve)
This method doesn’t work
From this DYN here, the one on the bottom is your suggested solution.
The other solution I came to on top of your suggestion, seems to work as well for other span of the model line but not further down.
I wonder if it’s because of the model being further away from the Project Base Point and it causes the DYN to fail? @@
The angle between facing orientation and the reds. You had the chance of coupling each red with the family instance about to be created before placing it. Pair them nicely then get the angle and rotate. Also beware of the direction of each red line, bottom left → top right and top right → bottom left looks the same but have opposite direction.
Or the angle between hand orientation and the grids, maintain 90 seems to be right thing to do.
How can I know which direction the Red Line is showing?
oh lets put some polygons or spheres at the start/end of each red segment and make them different in size. I use the lookup program in revit sdk but thats a separate install.
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Hi @Potato maybe you could use normal at parameter…perhaps ;)…
@sovitek Could you explain how SetRotation knows which axis it supposes to rotate around?
Hi guess family instance rotation is always Z axis
@sovitek I’m using rvt 25, I thought the result would be the one in blue. Instead, the node puts center of rotation someplace else?
what is it you select ?
oh it’s a ootb desk family comes with arc template in 25. I’ve checked its insertion, seems ok. wish I could give you a copy, but its in 25.
århhh yeah, have seen other have issue with that family, behave strange…havent tried myself…probably the families origin
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Yes - set rotation rotates the family instance about it’s origin, not an arbitrary point.
The vector of rotation is the normal of the placement plane.
To test this you can generate N duplicate copies of any family instance, select all N, build a range from 0 to 90 with N steps, and use the FamilyInstance.SetRotation node to identify the pivot point which will align with the insertion.
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heheh…smart 
cheers
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Getting rusty on this area but isn’t the family origin and insertion the same point?
M_Desk.rfa (1.1 MB)
Should be, yes.
What build is this?
(nevermind it’s 2025, or fast enough to open in 2025 anyway)…
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