Skeletal Method Question

[bradeneuropeArthur]

I was wondering what exactly the main reason is of using this method:

https://www.youtube.com/watch?v=JaiVSNIDMSM

Using a skeletal with sketches (skeletal.ipt).

Derive these sketches in separate parts (sketches.ipt)

place these parts in a skeletal assembly (skeletal assembly.iam)

create from derived parts geometry like extrude/thicken etc. (normal_parts.ipt)

and place these parts in a normal assembly. (normal_assembly.iam)

Instead of using the first ipt skeletal (skeletal.ipt) directly to create parts (normal_parts.ipt) and place them into the normal assembly (normal_assembly.iam).

This will reduce steps.

Is it the case to have the overview and that the initial skeletal sketch contains only sketches and surfaces maybe?

So is this chosen only for better overview?

@johnsonshiue @CGBenner 

Regards,

[CCarreiras]

Hi!

Skeleton Modelling is very useful, and there's many ways to apply the techniques involved in a skeleton system.

Maybe the video you suggest is not the better example.

Here's an example where using the skeleton and deriving surfaces will be very useful:

[bradeneuropeArthur]

For those who take customization by means of programming seriously are possibly steps beyond the others.

[johnsonshiue]

Hi Arthur,

The simplified workflow you described and the workflow shown in the video are both variations of Skeletal Modeling. Basically the structure of a final assembly is predetermined, yet subject to change. The derived parts from the skeleton (bodies, sketches, or parameters) follow the skeleton. Detail geometry is defined within the derived parts.

For certain complex assembly, you may have multiple levels of skeleton. This is particularly useful when your team collaborate with other teams. The levels help stabilize the design and accommodate the change from the skeleton more easily. Also, when a skeleton undergoes drastic change, the scope of impact can be managed more easily.

Many thanks!

[bradeneuropeArthur]

@johnsonshiue 

Than you refer to this method described in the help file of Inventor (Distibuted Pimairy), correct?

This method indeed is possible to split up in SubAssemblies and work together in a team to create the ToplevelAssembly.

[torbjorn_heglum2]

Agree with you, the method seems a bit complex. It looks old fashioned, like in the old days of Pro- Engineer and early Inventor. Using just sketches and work geometry is what we had to do before multibody was introduced sometime around 2010 I believe. 

Myself are using master models based on solids, as described here: master modeling tips&tricks

Torbjørn

[Desam]

The only reason I would use the doubled step approach is to add further detail to existing sketches or add new sketches in the first derived skeletal level.  If the level of complexity in the skeleton sketches is really high then the skeletons themselves and the derived parts can be very slow to work on/update.   See below for an example that got out of hand and should have been split up more!

[Odalv_Arkonski]

As someone experienced with using multibody and "wireframe" master parts (which include only sketches, planes, and similar elements), I find that multibody modeling offers a clearer visual representation of the overall design.

However, a limitation of using multibodies in Autodesk Inventor arises when parts are patterned in the assembly. If you create the pattern within the master part, it must be a multibody pattern—otherwise, the resulting parts won't accurately reflect individual components.

If each instance in the pattern is split into a separate body, it can lead to issues in the Bill of Materials (BOM). You’d need to manually rename each instance of the same part to ensure the quantities are correctly represented.

It would be very helpful if Inventor had a feature that could automatically recognize identical instances as a single part and carry over the pattern directly into the assembly.

[torbjorn_heglum2]

@Odalv_Arkonski, agree - multibody is a clearer way and it is possible to complete all design inside the skeleton. The part can be just a 'dumb' derive with no other features. Then all design intent can be kept inside the master model only, and all changes updated there.

We have found that it is meaningful to combine all 'reused' bodies into a reference body in the master model. I.e create a sketch driven pattern to place all copies of a body, then combine them into this reference body. 

In the assembly we place the master model as a reference backbone. Then the first instance of the part can be grounded at origin, the other instances can be created by an associative assembly pattern, referring the feature pattern in the master model. I think that was shown in the example above.

Torbjørn

[Odalv_Arkonski]

The idea of combining bodies into a reference body inside the master part actually sounds like a grat option. I'll definitelly try it in the future.

[bradeneuropeArthur]

That works (combine bodies) great for many years already.

Good to share that vision.