Surface in List can't be changed

I’m new to Dynamo an can’t find any help to my problem in this forum.
I want to check if elements are under a point cloud.
I made point cloud through a topo to a polysurface. And I got the xyz coordinates of the elements. With Polysurface.LocateSurfacesByPoints i get a List with NULL and Surface. the Null can be changed to false but the surfce can not be changed to true.Why might that be?


Your testing if any of your objects are the string “Surface”, which none of them is. Try adding the StringFromObject node before the ReplaceByCondition.

You could also check if your items are equal to null by using the IsNull node.

You could change your condition by “is not equal to false”.


StringFromObject worked.
Thank you.

Be careful where you place this node. If you place it after replacing the null values with “false”, all the “false” in your list will be strings and not boolean.

I still think that using the IsNull node is the best option.