topic Re: Mass of a simplified representation of a part? in 3D Part & Assembly Design

Mass of a simplified representation of a part?

BrianBoman — Fri, 20 Jul 2018 20:08:02 GMT

I found a nearly 4 year old post saying this was not possible. I am asking again because I have read about updates to simplified reps in more recent revisions.

Does anyone know if Creo 4 and Creo 5 includes the ability to update the mass of a part relative to an active simplified rep?

Thanks in advance.

Re: Mass of a simplified representation of a part?

MattewSpark — Sat, 21 Jul 2018 09:49:27 GMT

as far as I know it's impossible, but maybe I'm wrong

Re: Mass of a simplified representation of a part?

Chris3 — Mon, 23 Jul 2018 11:06:42 GMT

Just tested in Creo 4 and Creo 5 with the option force_upd_assem_mp_in_simp_rep set to yes and it didn't work for a part.

Re: Mass of a simplified representation of a part?

BrianBoman — Mon, 23 Jul 2018 15:05:06 GMT

Bummer. Thanks for trying.

Re: Mass of a simplified representation of a part?

jbush — Wed, 26 Jan 2022 23:49:37 GMT

I just tested in Creo 7 (with the option force_upd_assem_mp_in_simp_rep set to yes) and it didn't work for a part or assembly.

Still a bummer.

Re: Mass of a simplified representation of a part?

StephenW — Thu, 27 Jan 2022 14:46:10 GMT

I tested with Creo 4. I added the option and saved the config.pro. I closed Creo and reopened a new session.

When I opened the assembly as a simplified rep, the weight was updated to only be the part(s) included in the assembly.

I believe this option works as intended.

This option says it is only for Assembly reps, so I didn't test part representations.

Re: Mass of a simplified representation of a part?

jbush — Thu, 27 Jan 2022 18:19:44 GMT

Yes agreed, thanks for clarification. I tested different *part* representations with Creo 7 in both the standalone part and with the part in an assembly. In both cases the mass always reflects the master part representation. Bummer still no option to update mass properties based on part representations.

Re: Mass of a simplified representation of a part?

BrianBoman — Thu, 27 Jan 2022 19:25:59 GMT

I feel like this would be a great alternative to heavy assembly cuts. If I could use the default rep to hide a hole pattern that is match drilled in a higher level assy to make a drawing with the correct weight then install the same part into the higher level assy using the master rep it would save a lot of the pain that is related to using assy cuts even when the advanced options are selected.

Re: Mass of a simplified representation of a part?

StephenW — Thu, 27 Jan 2022 19:43:22 GMT

I completely understand your reasoning, but it is worth noting that PTC intended simplified reps (assy and part) to be used for large assy management purposes.

In this scenario, mass needs to be consistent with the master rep.

Using simplified reps for other purposes can lead to workplace madness!!! Sorry, meant to be a joke. I've done it and have driven co-workers crazy trying to understand what I was trying to accomplish!

Re: Mass of a simplified representation of a part?

BrianBoman — Fri, 28 Jan 2022 19:30:40 GMT

I just ran into an improper use case that drove me mad yesterday so I get that for sure. Not related to simp reps but still relatable.

That said, I hear you on using simp reps to defeature parts where the mass needs to come from the master rep. However, I feel like you could over come that and remove the need for assy cuts by adding a drop down under "alternate mass properties" that is "simp rep" to indicate you want the mass to be derived from the simp rep you have activated for said part.

Re: Mass of a simplified representation of a part?

BillRyan — Tue, 24 Jun 2025 15:29:56 GMT

Does Multi-Body help solve this problem? Has anybody tested the config setting in Creo 10?

Re: Mass of a simplified representation of a part?

Chris3 — Tue, 24 Jun 2025 16:02:50 GMT

I tested with and without the config in 12.4.0.0 and there is no change. When a feature is removed in a rep, the mass properties still reports the master rep mass.

Someone can correct me if I am wrong, but I don't think working with bodies helps this issue. The part rep definition in Creo 12.4.0.0 hasn't changed and there is no option to create a rep using bodies (boolean features are hidden when you go into part rep definition).

Re: Mass of a simplified representation of a part?

BillRyan — Tue, 24 Jun 2025 17:57:25 GMT

It is wild that the mass doesn't change when geometry shown on the screen changes. 😞

Re: Mass of a simplified representation of a part?

StephenW — Tue, 24 Jun 2025 18:17:53 GMT

PTC's intended use for simplified reps (parts and assemblies) was for large assembly management (system resources like memory).

Using it for product variation is not what intended when implemented .

When used for large assembly management, I do not want my mass changing when I remove feature details (parts) or components (assemblies).

Re: Mass of a simplified representation of a part?

BillRyan — Tue, 24 Jun 2025 18:26:56 GMT

PTC gave the customer the option to handle both scenarios for assembly. You can have the config option called "force_upd_assem_mp_in_simp_rep" set at no which we have as default too. But we can change that setting to yes to see the weight rollup based on what is active and shown on the screen. I agree simp reps in parts should not be used for orderable parts...but my users use case was quick weight rollups on a development part.

Re: Mass of a simplified representation of a part?

StephenW — Tue, 24 Jun 2025 18:34:53 GMT

Good point. I do like the option. I have used it for some shipping simplifications where I need to remove some items for shipping and for a few other odd scenarios that don't make any sense. Just a good tool to have in the toolbox.