Lookup Table Creation

[anthony_iskandar]

I wanted to make double 45 degree PVC elbow, nested family, I started by using a Revit basic PVC elbow, I use the 45 degree, and from the Revit original PVC bend elbow file I put those 2 of 45 degree elbow, align and connect it, but the problem, when I load it in my project, looks like the position is weird, which I think it's caused by not changing the lookup table, CMIIW. How should I change it? Since I don't have any resource to the pipe manufacturer, as I just simplify it by myself.

[fabiosato]

Hello,

It does not seem to be a lookup table problem, can you send the family for inspection?

[anthony_iskandar]

Hi, sorry for late reply, something urgent came up.

Here is the family, it was not a proper one, I just use a default revit bend family, and just put here and there and hoping the modification is enough for the family to work. 

[fabiosato]

Hello,

I did a quick review, and it seems to me that the way you used to create this family will only works if the angle is exactly 90 degrees.

For any small angle variation you will have problems.

[anthony_iskandar]

Yes, I just want to use it for 90 degree only but it doesn't work well too. If I use it in Routing Preferences, the result will be like in my first post, I guess it's because of the lookup table, no?

[iainsavage]

This other post might give you some clues:

https://forums.autodesk.com/t5/revit-mep-forum/i-need-to-create-a-family-with-45-bend-and-nested-str...

[iainsavage]

I tried your fitting in a sample file and it sort of worked okay.

In smaller diameters it was fine, but in larger diameters the two elbows overlap each other. 

The connections though were okay:

To sort out the overlap issue you need to have some means in the family of moving the lower elbow leftwards and downwards and the upper elbow upwards and to the right whilst stretching/shortening the piece of pipe between them (using a formula and constraints).

[iainsavage]

I just noticed as well that the lookup table in the family is M_Bend - PVC - Sch 40 - DWV.csv whereas the table which you uploaded is M_Double Bend - PVC - Sch 40 - DWV.csv.

When I loaded the double bend table and changed the lookup table name parameter the family does still appear to work. It even works okay (apart from the overlap) with "not found" sizes which are not included in the lookup table.

[Sefanja_Verkaik]

I have looked into the family, however alot of excess information that is not needed really clashes with the functionality. I can list a bunch of problems with the family, but I would advice starting from an empty family template. Alternatively you could use Revit families that are available from product firms.

Biggest issues I have found:

The routing preference seems to fill in an extra Union or transition. (From picture)
All formulas in the file are based on the 45 degrees from the linked family, but the fitting is designed as 90 degree
The X and Z axis for both 45 degree fittings are not adjusted for the extra length needed to create a 90 degree angle.

This is why the family works with size 32 but no other sizes.