Derived Component mass error

[whunter]

Hi all;

I think there might be a bug in Inventor 2012 with regards to derived components and their physical properties, otherwise I've never noticed it before...

If I derive a component and use an IAM as the Base Component and choose the 'Single composite feature' as the option then the physical properties of the newly created derived IPT is the same as the original IAM. That is expected behaviour when you choose one of the Solid options, but a Surface shouldn't have a mass - by definition.

If I use an IPT as the Base Component, I get the expected behaviour, i.e., a surface doesn't have a mass.

The whole purpose of creating a 'Single composite feature' as a surface is unnecessary if it's going to have physical properties...

Anyone else having this problem?

Regards,

William

[Daniela_Koloszko]

The behavior is the same also in the previous versions of Inventor, after the Shrinkwrap functionality has been introduced. This derive option "Single Composite feature" came with Shrinkwrap. The reason to create shrinkwrap part is to use the shrinkwrap part as substitute of the source assembly and the need to keep the mass to make sure the substitute part works as the source assembly in another top assembly. Also, the reason that this works differently for a part is based on the fact that the surface option there is a legacy option and does not come from Shrinkwrap. If you want to keep the mass zero in the derived assembly, you can first use the solid output option and then to derive the solid part second time with the surface output option.

[whunter · Accepted solution]

Ouch , I'm obviously confused... The Shrinkwrap argument makes perfect sense.

Thanks,

William

[pierre.masson]

Or if you have been building some solid in a part based on Single Composite derived assembly, you can open the source Assembly, and override the mass to 0

[James_Ritorto]

You know what would be really handy... an tickbox option to include mass or not include mass when derriving a surface.

(unless this has been included in 2015 release??)

I understand why it has been done for shrinkwrapping but realistically surfaces should not have a mass, especially if that is the case for parts.

Why should it be different for parts and not assemblies? This is quite confusing without an explanation in-built into the software.

My mass errors had me puzzled until i found this post.

I personally think having to derrive twice just to make a reference part seems a bit unnecessary and takes up additonal storage space and time, and overriding the assembly mass would also create issues with drawings relating to that assembly so thats not a good solution either.