0 mass shown in an assembly

[pdybeck]

I have an assembly composed of parts that have a definitive weight- on the order of 70 lbs. When I look at the top level assembly with these parts in it and ask for the weight of the assembly on the mass properties button, it calculates the weight at 0 lbs. Has anyone seen this before? Could I be doing something wrong? I have tried Cntrl Q, save, to no avail.

Pete

 

[TheTick]

Are the parts not fully resolved (lightweight)?

Are the parts solid (vs. surface bodies)?

Is density in the part files properly set?
Free macro and addin available that sets density for multiple components in an assembly:
<

http://www.esoxrepublic.com/freeware/index.html>

Due to illness, the part of The Tick will be played by... The Tick.

http://www.EsoxRepublic.com

 

[pdybeck]

Parts are solid, have the correct densities applied, and are fully resolved in the assembly. I am at a loss.

 

[CorBlimeyLimey]

1) Does each part "weigh" correctly when opened seperately?

2) Does each part "weigh " correctly when selected individually from within in the assy?

3) Do you have the same problem with other assemblies on your computer?

4) Do you have the same problem with the assy on a different computer?

5) Do all the parts become highlighted in the grapics area when using the Mass properties tool?

6) Have you tried a Repair of SW?

from (the City of) Barrie, Ontario.

Support bacteria - they're the only culture some people have

 

[pdybeck]

1) Each part weighs correctly in its own window
2) Each part weighs correctly when selected in the assembly
3) There are no other problems with other assemblies
4) The same problem exists on other computers when trying to find the mass of this assembly
5) All the parts become highlighted
6) Have not tried a repair, but it seems very unlikely this is the cause. The machine I am running just had a fresh install of 2004 SP 3.0 on it as it is a brand new machine.

 

[CorBlimeyLimey]

Strange ... Are there many parts involved in the assy? Can you easily make a new assy to see if the problem repeats itself? If so, I suggest you check assy weight after each part is inserted to try & find a "culprit".

Let us know what you find.

from (the City of) Barrie, Ontario.

Support bacteria - they're the only culture some people have

 

[pdybeck]

In my spare time, I'll do what you suggest. The assembly is a couple hundred parts, so it won't be quick and dirty. First I'll just make a copy of the assembly file and see if the original assembly file itself was the culprit in that it may be corrupt somehow. Thanks for the suggestions.

Pete Yodis
Harold Beck and Sons

 

[SBaugh]

Try saving the assembly as a single part. Then open that part up and try and get a Mass Property off that.

Save it either as

1) Exterior Components

Or

2) All Components

Worth a try at this point IMO.

Regards,

Scott Baugh, CSWP

http://www.3dvisiontech.com

http://www.scottjbaugh.com

If you are in the SW Forum Check out the FAQ section

To make the Best of Eng-Tips Forums FAQ731-376

 

[ctopher]

If your parts are very small...have you checked: When you do mass, look at options and change decimal places out to maybe 8, then to mass. Does anything show up?

 

[pdybeck]

The parts are not very small. Some have masses of 25 lbs or more.

 

[TheTick]

running out of ideas.....
if I could only reach my bat-belt....

In the mass properties window, make sure the assembly is shown as selected. If it is not selected, select the top level from the icon in the feature manager tree and hit the "Recalculate" button.

One more thing to try...

Make a new temporary assembly, and put your current assembly into the new assembly as a component and see if you can get mass props that way.

Due to illness, the part of The Tick will be played by... The Tick.

http://www.EsoxRepublic.com

 

[CorBlimeyLimey]

Do you have any sub-assemblies in the main assy? If so do any of them have the same problem?

On a similar vein to TheTicks suggestion & as a very quick check, start a new assy & just drag & drop all the parts (en masse) into it. Don't worry about mating the parts ... just get a collection of parts & then try the Mass properties.

BTW, how many mates are in the problem assy? If there is more than 300 in the Top Level assy, that's where your problem may be. How does the size & number of mates of the problem assy compare with others that are OK?


from (the City of) Barrie, Ontario.

Support bacteria - they're the only culture some people have

 

[pdybeck]

I've been able to locate the source of the problem by supressing parts and subassemblies one at a time and checking the top level weight. By doing that I was able to find the subassembly that was the culprit. Furthermore I found a part in the subassembly that was the root of problem. For some reason it will not calculate any mass properties for the part. I suspect it has to do with the fact that it was downloaded from AMP's (Tyco) website. It is an imported IGES file. Does anyone know what I could do to remedy the situation? For now I will try to round trip it to see if that fixes it. Thanks for the help.

Pete

 

[SBaugh]

Does the file show any Mass Properties? If not, the file is most likely a Surface model and is in need of repair to make it into a Solid. To repair a file see my website on repairing Imported models -

http://www.scottjbaugh.com/Tips_Tricks/Repair_Imported_Models.zip

Regards,

Scott Baugh, CSWP

http://www.3dvisiontech.com

http://www.scottjbaugh.com

If you are in the SW Forum Check out the FAQ section

To make the Best of Eng-Tips Forums FAQ731-376

 

[CorBlimeyLimey]

pdybeck
I guessed it would be at the part level hence the first question in my first post ... anyway I'm glad you found the problem.

For future reference, rather than "supressing parts & sub-assemblies one at a time and checking the top level weight", you could add a Mass properties column to a BOM & have it list all the parts. Using indented format, you will be able to simply read off the individual weights of all the parts & easily spot a weightless one.

from (the City of) Barrie, Ontario.

Support bacteria - they're the only culture some people have

 

[pdybeck]

Thanks for all the help and suggestions. It turned out the problem was in a chamfer feature that was causing the solid body to be a non-solid. I was able to roll back above the chamfer and check mass properties, but as soon as I rolled past the chamfer, the mass of the part could not be calculated. It seems there should have been a warning that the chamfer failed or at least was causing issues, but there was none. The imported body was actually OK. I will submit this part to my VAR.

Pete