Surface manual / automatic selected for placing facebased family

hi everyone,

I have made an script that filters the top face of an structural framing element. but when I put this into the familyinstance.byface node it will give an error… when I manually select the faces then its working fine.
my problem I don’t want to select every time an surface when I also can filter this surface. does anyone have a clue why this isn’t working? both are surfaces and I cant see the difference, see also script.

Whats the error say?
The watch may look the same but the structure (list structure) of what you feed into FamilyInstance.ByFace may be different.

screenshot of warning when I put filtering top face into the familyinstance.byface node.

Its saying that basically you’re not putting in the correct format into ‘face’ input

try using Object.Type node in both your manual and your filtered results to see what format your data is.

I have a feeling your manual one is a ‘revit’ face…but you filtered one is a dynamo ‘surface’ or something along those lines…

object.type seems the same… or do I use the wrong methode? I have also filtering the surface by topology.faces but did didn’t do the trick.

I have added the .dyn file if you want to look into it. filter topfaces.dyn (89.7 KB)

I do have the solution, I had to use Element.faces instead of Element.geometry and then it works :wink:


1 Like

Hi. Cool to see someone else trying to select a specific surface from a modeled element. I am having a similar struggle.

I want to be able to select a floor and Dynamo automatically select the bottom surface. (to remove user error) I am having trouble and would love your advice. One difficulty is that the floor is sloped so the bottom surface won’t be pointing 100% down.

I tried picking the bottom face based on the normals. But I got stuck when the normal needs to be -1=>0 I was not sure how to create a parameter between these two numbers.

Is there an easier way to select the bottom face of a floor?

I’m creating a script that automatically aligns all beams and cols (that terminate on that level) to the bottom of floor.

Hi I’m interested in understanding this code you made. I tried it on my project and it seems to work really well!

Can you explain the Code Block = 0.5 which you then plug into the U & V parameters of the Surface.PointAtParameter node? Why 0.5? What is that node doing?