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gamba-boy4-Participant
4-Participant
September 8, 2026
Question

frame multibody

  • September 8, 2026
  • 12 replies
  • 162 views

We are currently considering how best to design a frame using Creo Multibody, and we would like to ask for your advice on the most appropriate workflow.

From a design perspective, the frame can essentially be considered as one box-shaped structure. Therefore, we would prefer to design the entire frame as a Multibody Part rather than creating and managing multiple individual Parts from the beginning.

However, from a manufacturing perspective, the actual frame is divided into four sections: the top, bottom, left side, and right side. Each section is manufactured and welded separately, and these four sections are eventually assembled to form the completed box-shaped frame.

This creates a difference between the way we would like to design the frame and the way it is actually manufactured.

At the moment, we are not sure which approach would be the most appropriate in Creo:

  • Keep the frame as a single Multibody Part throughout the design process and somehow use the individual bodies for manufacturing and documentation, or

  • Use the Multibody Part as the initial design model, and later create individual Parts from the bodies and assemble them according to the actual manufacturing structure.

We understand that both approaches may be possible, but we are unsure which would be considered the better practice, particularly when considering drawings, assemblies, BOM structure, and design changes.

Our ideal workflow would be to keep the design process as simple as possible for the designer, while still being able to represent the actual manufacturing structure correctly when the frame is produced.

Could you advise us on how you would recommend approaching this type of design in Creo?

We would also appreciate any suggestions for a workflow that balances the advantages of Multibody modeling with the need to eventually represent the four separately manufactured and welded sections.

    12 replies

    jchance12-Amethyst
    12-Amethyst
    September 8, 2026

    The decision tree can be complicated and long and its something we’re struggling with internally. 

     

    1. is IFX the better module?
      1. We don’t do top down internally because its not KISS(for better or for worse)
    2. Are you making shop drawings or are you making fabrication drawings that is fabricate by a vendor?
      1. If you’re making the shop drawings for internal weldment then i would make them as separate parts.
      2. THAT leads into…
        1. Do you make an assembly?
        2. Are you using a skeleton part in the assembly?
        3. Do you make a multibody part and then do “create an assembly from bodies?”
          1. what is your plan for that part to be known as the master model for the weldment assembly so someone else down the line can pick this assembly up?
          2. Threads can be weird when placed in the body or assembly(not showing the cosmetic thread)
      3. You can then give each part a defined part number and can have them be on a BOM
    3. If you’re making this for an outside vendor to assemble then:
      1. You can stop at a multibody part if you want
      2. You can still follow the path above and choose what you want
      3. You may need to have a user understanding that maybe small weldments are a simple multibody part and maybe large weldments become an assembly of parts that were created from bodies.

     

    Internally, we haven’t found the right path.  You need to understand the learning curve of multibody and if some users can do it.  Do you already do Top Down?  Do you already use Skeletons?  Can your models be passed from old user to new user and vice versa? Do you like to copy and reuse parts for other assemblies? You can’t do that with assemblies made from Multibody parts(its linked to the existing part and would be a reference nightmare)  Its complicated and every group will have a different way of doing it.  I personally asked PTC how they intended us to use multibody weldments and they didn’t have an answer for me.  At least with Solidworks they have a weldment function(IFX for PTC...) but their weldment tool is probably easier than PTC’s.  

     

    We don’t do internal shop drawings for weldments and everything is fabbed at a vendor.  I have done all 3 different ways to varying success. I’m not sure how well some of my models can be picked up by someone else and thats a problem.  

    gamba-boy4-ParticipantAuthor
    4-Participant
    September 9, 2026

    Thank you very much for your detailed response. It was very helpful.

    Our situation is a little different from yours because we manufacture the frames internally.

    The designers mainly need to create and submit the drawing of the completed frame as a box-shaped structure.

    However, for manufacturing, we are considering dividing the CAM data into four sections:

    • TOP

    • BOTTOM

    • LEFT

    • RIGHT

    These four sections are fabricated separately and then welded together to create the completed frame.

    In addition to the overall frame drawing, we would also like to create a separate welding drawing for each of the four sections, so that the manufacturing process is clearly defined.

    So our concept is something like this:

    FRAME_MASTER.PRT
    ├─ TOP Body
    ├─ BOTTOM Body
    ├─ LEFT Body
    └─ RIGHT Body

    The overall frame drawing would represent the completed box, while the four individual sections would be used for CAM and their respective welding drawings.

    In this situation, I am wondering what you would recommend.

    Would it make sense to keep the Multibody Part as the master model, create individual Parts from the four Bodies, and then create an Assembly from those Parts for manufacturing and BOM purposes?

    Or would it be better to create an Assembly using a Skeleton/Top-Down approach from the beginning?

    Our main goal is to avoid having to maintain the same design information in multiple places, while still being able to produce:

    1. An overall drawing of the completed frame

    2. Individual CAM data for TOP/BOTTOM/LEFT/RIGHT

    3. Individual welding drawings for each section

    4. A proper BOM and part numbers

    If you were designing and manufacturing this type of frame internally, which workflow would you choose?

    I would especially appreciate your opinion on which model should be treated as the master model in this situation.

    Thank you again for sharing your experience. It has given us a lot to think about.

    tbraxton
    tbraxton22-Sapphire II
    22-Sapphire II
    September 8, 2026

    Use the multi-body model of the complete box as a master model (top-down) to drive derivative models and drawings to support your PDM and manufacturing/fabrication documentation. Consider the multi-body master as a design model (not a representation of BOM or fabrication structures). You can then use save body as part and use these parts to build assemblies as required for BOM structure or fabrication documentation. Make a plan for how you will handle the definition of the welds and include them where it supports your workflow.

    Make sure that you understand the concept of construction bodies in this context as it may be useful.

    jchance12-Amethyst
    12-Amethyst
    September 8, 2026

    do you use it like:

    • ASM File
      • Skeleton.prt
      • .prt files from each body in the skeleton

     

    or

    • .PRT file that is on its own
    • Create .ASM file
      • Save bodies from .PRT file to individual parts that are assembled into the .ASM file
    tbraxton
    tbraxton22-Sapphire II
    22-Sapphire II
    September 9, 2026

    Of the two options above I would use the latter. I typically would not include solid geometry in a skeleton model so that would eliminate your first option as bodies are solid geometry. This has been generally accepted as a best practice since the introduction of skeleton models to Pro/E some time ago. I suppose a case could be made for including only construction bodies in a skeleton part, but I would need to think that through before suggesting it. Depending on what design intent you would define using a skeleton it could likely be redundant to that defined in the multibody master model.

    The concept of multibody in Creo uses a part to define multiple bodies. You have the option of designating bodies as construction bodies if needed. The master model (part with multiple bodies) represents the solid geometry required to create the assembly or assemblies in your design space. You then use the master model to split off the parts by saving each body as a part. Be deliberate about how/where you define part level data (material etc.) you can make your life easy or hard if you get this wrong so consider how the data is used in your process before deciding on a standard.

    Once the individual parts are defined using the master model geometry through the save body as part function you can then configure them as needed in assemblies to support CAM, QA, fabrication documentation etc. When done correctly any geometry change made to the master would propagate to all derivative data sets (models, drawings, etc.) .

    BenLoosli23-Emerald III
    23-Emerald III
    September 8, 2026

    I have usually modelled things as they are manufactured. Individual frame pieces into the 4 side assemblies and then into the  final frame assembly. This allows drawings to be created where needed as well as the creation of multiple BOMs. You can have your engineering BOM and then restructure it as needed for manufacturing BOMs. This does require using WTparts and MPMLink to do the BOM restructuring.

    Multipart body parts have their uses but I would not use them for a welded frame asemb;y.

    tbraxton
    tbraxton22-Sapphire II
    22-Sapphire II
    September 8, 2026

    To offer another perspective not specific to weldments. I do not design the same type of products/designs every day and work across many different industries so keep this in mind when considering these comments. 

    I typically would not conform to manufacturing/BOM structure when designing in Creo. I structure the CAD data to support the team/workflow to lower the time to both create and modify the design in CAD.  When the design gets released for certain gates then an assembly structure following process/assembly etc. would be created to support workflows. The ROI with this approach increases with complexity of the design IME. Creo and the people to effectively use it are relatively expensive in $ and time so anything done to drive down cycle time to get a design done is usually desireable.

    If I was designing the launch pad support structure for a rocket (thousands of parts) then I would not use a multibody master but for the OP description it should work nicely if done thoughtfully.

    My recommendation would change based on the understanding of the team, deliverables, and workflows to make a recommendation on how to realize a KPI associated with design engineering and analysis.

    Michael_Bourque
    Michael_Bourque14-Alexandrite
    14-Alexandrite
    September 9, 2026

    Have you considered AFX? You could easily create a skeleton and drive the plates from skeleton. They you would have separate parts that can be augmented per your needs. 

    Michael Bourque
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