Parameter's storage type is not string

Replacing one family type with different more complex type.

Code is working fine for the top half of work. Making the families the same width. It pulls the old data and adds to the new.

Second half, taking same family and setting a parameter that is length and instance controlled. Same type of parameters, length type, will not insert to new family. Both families have been modified to have this parameter instance driven. Not seeing the old data come in. Any ideas? Will continue to work and drill down to first problem. Just wondering if I’m using the right nodes to pull the data by.

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Apologies, it’s hard to give much help without seeing the families, I agree that Dynamo is being contrary… Is there any possibility of a legacy family with the same type name having been mistakenly selected?

Hope that helps,


Hi Steve,

While it’s definitely an odd one, I’m guessing it’s just a conversion issue between types and units. Try converting the result of the Element.GetParameterValueByName for the First Stud Spacing through a String To Number node. Check the results of this for number value and convert your units if necessary before plugging the new values into your Set Parameter node.

Another issue may be the parameter storage types not aligning between the two family types. Check both the old and new family types in the family editor and make sure that the First Stud Length parameters are set to be length type parameters.

If it’s still giving you issues, it may just be a small corruption and you can try deleting the Get Parameter Value node and replacing it with the same kind of Element.GetParameterValueByName node.

Let us know if this works!