Mass not correct in assembly

[karthur1]

I was checking my prints and noticed that the mass for the assembly was not shown correctly.  The mass for each component is correct, but the mass for the assembly is less than the total mass of the parts...huh.... how can that be????

Watch this video.  The mass for my assembly is reported from iProperties as 10 lbs, but the mass for one of the parts is 60lbs.  I would expect the mass for the assembly to be at least 60 lbs, but it is not.  I tried a "Rebuild All" and an "Update Mass" on my assembly, but that did not fix it (30 sec mark in the video).

This assembly is part of a much larger assembly (around 35,000 parts).  There are several more assemblies doing this and I need to get the mass correct.

I am using 2013 x64, SP2.

The problem files are attached.

[blair]

Not sure what is going on, first of all the end bracket 236-090 is set to Read-Only in the file properties and was showing a mass of .153lb which is incorrect.

I changed the file properties and then just changed the material to Mild-Steel. It then gave me the 60.438 lb for the I-beam and the end brackets changed to 1.20lb. The assembly no displays the correct mass of 62.92lb

[chris_in_stockholm]

I noted then same problem in 2013 when doing FEM on an assembly.

Comparing changes in stiffness vs mass.

Changing part dimensions did not change mass in toplevel assy.

Autodesk confirmed the bug and I have been told it has been fixed in 2014.

I have not checked. I don't care because I have been allowed to use SolidWorks

even though the company use Inventor. We are in the process to throw Inventor out 🙂

Decision is very close 🙂 🙂 🙂

Inventor is a joke. It's so tedious, inefficient and lacking in some aras it amazes me that

any company affords to waste time using it commercially.

[blair]

Not quit sure what your post with this has in common with this problem.

Also I've never heard of FEM in Inventor.

[chris_in_stockholm]

Mass not correct in assy!

Changing a part and mass at  toplevel assy reporting same mass.

No change in reported mass.

Error calculating mass!

Problem related to thread topic!

What is your probelm?

Don't you know what FEM is?

FEA/Simulation!

[karthur1]

Both parts should be Read-Only cause they are in checked into Vault. 

I "thought" that doing a rebuild all on the assembly would correct it but it would not.  I opened the -090-wb and did a rebuild all on it, then when I went back to the assembly and saved it, it gives me the correct mass for the overall assembly. I had to go through all my sub-assys that had the wrong mass and do this.  Only took about 10 minutes to do that, but it took a while to figure out what was wrong.  No idea "WHY" it is like this.  Makes me nervous going forward.

I always thought that Rebuild all would rebuild ALL parts in the assembly and subcomponents.  That might be different now, IDK.

The mass in my top level assembly went from 126,000 lbs to over 192,000 lbs.(just a little difference).