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Surface model -> multiple parts. Best practice?

johej

New member
Hello
I have a Surface model. (see pic)

From that model I need to create 6 parts. Housings of an instrument.

How do I do it the best way?

I was thinking, creating an assembly with the Surface model as first part
Copy surfaces to new parts.
Keep or break external referenses?
Then trim surfaces and thicken.

Is there a better way?
Best Regards
Magnus
 

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your approach sounds reasonable and simple I would follow that way

of course there are many other, different solutions but, if maintaining/having external refs. is no issue to you, there is no reason to make it more complex
 
Hej Magnus!

I would probably go for "shared data" - "copy geometry" in this case, depending of what creo licence you got. Regarding keeping the referenses , i would keep them for the simple reason that if you want to update the geometry, you do it in your "master part" and your "housing parts" will follow that update.

//Tobias Larsson
 
If you have advanced assy, I'd convert your master model to a skeleton first. Several advantages to using an actual skeleton model - they can be filtered out of BOM reports & tables, they are ignored for mass properties calculations and they automatically appear at the top of the tree.

To convert to a skeleton (this is for Creo2):


  1. Create your assy
  2. Within the assy, create a new part (find the 'create' button in the 'Component' section of the 'Model' tab)
  3. Select 'Skeleton Model' as the type in the 'Component Create' dialog and give it a name
  4. In the 'Creation Options' under 'Copy From...' click browse and open your existing surface model.

You now have a skeleton that is an exact copy of your original.

I would then create publish geometry features in your skeleton for each component that you need to share geometry with. Add in all the surfaces and datums that you'd like to share. I liek to right click on these and place them in the footer.

Then, in each component, create a copy geometry feature that references the respective publish geometry in the skeleton. I like to do this in the assy rather than using external if the component will not be shared with other assys. That makes it easier to understand the relationship between the two parts that are sharing geometry because the geometry is copied via their relative positions in the assy.

This technique, if done with forethought, is very powerful and robust.
 
How is your method better than using a family table?
I've never used copy geometry before and wondered how it may be advantegeous compared to the family table.

If you have advanced assy, I'd convert your master model to a skeleton first. Several advantages to using an actual skeleton model - they can be filtered out of BOM reports & tables, they are ignored for mass properties calculations and they automatically appear at the top of the tree.

To convert to a skeleton (this is for Creo2):


  1. Create your assy
  2. Within the assy, create a new part (find the 'create' button in the 'Component' section of the 'Model' tab)
  3. Select 'Skeleton Model' as the type in the 'Component Create' dialog and give it a name
  4. In the 'Creation Options' under 'Copy From...' click browse and open your existing surface model.

You now have a skeleton that is an exact copy of your original.

I would then create publish geometry features in your skeleton for each component that you need to share geometry with. Add in all the surfaces and datums that you'd like to share. I liek to right click on these and place them in the footer.

Then, in each component, create a copy geometry feature that references the respective publish geometry in the skeleton. I like to do this in the assy rather than using external if the component will not be shared with other assys. That makes it easier to understand the relationship between the two parts that are sharing geometry because the geometry is copied via their relative positions in the assy.

This technique, if done with forethought, is very powerful and robust.
 
That's a bit like asking which is better, an apple or an orange. The two techniques have different purposes.

Family table are great for parts that need to be and remain identical except for minor differences. The more differences between the parts, the more difficult the family table will be to create and manage. A fastener database is a classic application of a family table, another would be an extruded profile cut to different lengths and with different hole patterns. In the latter case, if the profile changes you want all the pats to update since they all come from the same die, but if one part gets a new drilled hole it may not apply to any of the others.

Top down design techniques I've described are great for developing the product at a top level - the entire form, parting lines, screw locations, etc. - and splitting it up amount parts that don't really share any geometry but have to relate to each other. This seems like what he's after here, he has an overall form that he's developed and wants to maintain, but the RH panel,for example, doesn't really share any actual geometry with the LH. The skeleton driven approach allows you to develop the overall form, as he's done, and share the specific parts of it down to the components that need it while maintaining the relationship back to the overall form.
 
Perhaps to say they don't share any geometry isn't accurate, but much of their geometry isn't common.

Take his image above. I'm assuming the red lines represent part breaks. Some parts share surfaces which span over the part break, for others the part line edges are the only thing in common. Those edges or the surfaces must align, and that will come from the skeleton model, but most of their geometry isn't shared. The lower front panel (1), for example, has no geometry in common with the back or the upper center.

I suppose that one could use a master model with all the geometry and then use a family table to exclude features or control cuts that break it into parts. That table would be large and cumbersome and each part, no matter how small, would carry the burden of the feature set of the whole.

In contrast, in my extrusion example, every part has nearly the same set of surfaces adn features. Family tables make a lot of sense there.

I hope that makes it more clear.
 
Thanks for all the tips. :)
I have followed my initial thoughts and so far it goes well.
Best regards
Magnus
 
Interesting. I've been using this method for years but without defining my master part as a skeleton. I really like the fact that it shows up in the assembly as the first feature. It's a clear indication to future users that the parts are driven by a master part.

Are there any drawbacks to defining your master as a skeleton?

If you have advanced assy, I'd convert your master model to a skeleton first. Several advantages to using an actual skeleton model - they can be filtered out of BOM reports & tables, they are ignored for mass properties calculations and they automatically appear at the top of the tree.
 
The only drawback I can think of is that it does require the Advanced Assembly Extension. That may inhibit the ability for others who do not have AAX to work on it.
 

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