topic Re: Best way to model an adaptable frame? in Inventor Forum

Best way to model an adaptable frame?

JoshBretscher — Wed, 25 Apr 2018 16:25:33 GMT

I'm currently trying to model a frame that will change in height, length, and shape to a certain extent. It uses a lot of custom legs and joints, and as the height and length change, all of the joint angles and even the shape of the end of some legs change as well. My initial thought was to use the frames within inventor (adding my own custom profiles for the legs), but the joints were too complex to model through this method. Next, I tried making iParts (there are a lot of variations for each leg that can be suppressed for other legs) for each part only to realize that iParts can't really be made to be adaptive within assemblies. Now I'm thinking I should just make each part on it's own so that it can be adaptive in an assembly, but am open to suggestions.

Re: Best way to model an adaptable frame?

SBix26 — Wed, 25 Apr 2018 17:04:41 GMT

Multi-solid modeling is my go-to for adaptable assembly modeling. That means essentially modeling all the parts, or a significant subset of them, in one master part as individual solid bodies. These are then derived into individual part files (entirely associative to the original bodies), and these part files are assembled into subassemblies and top level assembly. Any changes are easily made in the master file, then click the Update button in your assembly. It really is just about that easy.

For your frame, I would either publish your profiles to the Content Library as Features, as iFeatures, or simply keep them in the master file as sketch blocks.

If you can post a small example of what you're working on I'd be glad to show you how this method could work for you.

Edit: what version of Inventor are you using?

Sam B
Inventor Pro 2019.0.0 | Windows 7 SP1
LinkedIn

Re: Best way to model an adaptable frame?

JoshBretscher — Wed, 25 Apr 2018 17:18:22 GMT

Sorry I can't share what I'm working on. I'm using Inventor 2018 professional version. So basically you're saying the best way to do this is create a master part for each kind of leg/joint. For instance, if two legs were the same, except one has a mitered end, they would be two different master parts. Then from these master parts create copies of the file and use them as adaptable within an assembly? Sorry if I'm misunderstanding, still learning.

Re: Best way to model an adaptable frame?

doug.johnston — Wed, 25 Apr 2018 20:53:16 GMT

I have a similar situation and I used Frame Generator to create my frames.

My frame sketches have custom parameters (LxWxH) that control the overall size and vary from project to project. All the frame members are modified by using the trim command in FG. Any "special" features (eg. holes, copes, etc.), I created with basic modeling commands.

If you have custom legs, then try and model them as iparts and publish them to the content center so you can use them in FG.

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Re: Best way to model an adaptable frame?

torbjorn_heglum2 — Wed, 25 Apr 2018 21:18:18 GMT

I would definitely go for a multi-body master part, as proposed by Sam B. Here you are free to use all features available in the part environment, and you can create all kind of shapes you need. I.e beams, plates and more advanced shapes can be combined and adapt to each other as required.

The structure below is controlled by one master part, and updates all affected parts when some of the main dimensions is changed. I don't see any other method offered by Inventor that can do this as efficiently as use of a master part.

Torbjørn

Re: Best way to model an adaptable frame?

SBix26 — Wed, 25 Apr 2018 21:31:07 GMT

@JoshBretscher

What I'm trying to avoid is spending the time to create something to show you and it's nothing like what you're working on. Can you create a small assembly similar to what you're working on?

In any case, you misunderstood what I wrote, so I'll try again:

The master part, or perhaps a better term is "layout", contains the model definitions for all of the parts in your frame, or perhaps even more of the assembly, or all of it. Each separate part of the assembly is modeled in your layout as a separate solid body (use the New Solid control when creating the first feature of each part). The advantage is that all the relationships between parts, such as holes, notches, etc. are easily modeled within that same part file. That means that when you change a hole location, the other solids that have features that depend on that hole location change, too.

Then each solid body is derived into a separate part file where material, description and part number is assigned, and these parts are assembled into the actual assembly. If there is no movement involved in the assembly, the parts can all be placed at the origin and grounded, no constraints or joints needed.

All changes are made in the layout file. After that, clicking the Update button in the assembly cascades the changes through all the affected parts.

Deriving the separate part files can be done manually (start a new part file, select the Derive tool, select the layout file, select the solid body to be derived), or Inventor has tools to automate the process-- Manage > Layout > Make Part & Make Components.

For parts that are identical, I may just skip modeling the duplicates; or I may model the duplicate bodies but skip deriving them into separate parts. Depends on the situation.

Again, if you can provide any kind of stripped down example, or an image or link that illustrates something similar, I'd be happy to show you what I mean.

Sam B
Inventor Pro 2019.0.0 | Windows 7 SP1
LinkedIn

Re: Best way to model an adaptable frame?

JoshBretscher — Thu, 26 Apr 2018 13:58:49 GMT

@torbjorn_heglum2 gave a pretty relatable example in his picture. For example, if I wanted to be able to quickly change the dimension of the rectangular end where it appears it attaches to another device. This would cause a lot of changes in length and angles around the joints. I now get what you are saying by master part. The idea of modelling multiple solids in the same part file went over my head in your first response. There's only around 4 different leg profiles I need to use for this frame. However, I would like the length and angle of certain features on each leg to change as needed as the length and height of the overall frame changes. For these changes to occur, do I make each derived part adaptive so that in the assembly they will change according to their constraints? Or in the master part do I model every solid (even legs that are the same in every way except for length) in a way that every feature is related to each other. If that's the case, this would be very tedious as there will be about 100 of each leg type, just all with different lengths and angled cuts on the ends.

Re: Best way to model an adaptable frame?

doug.johnston — Thu, 26 Apr 2018 16:33:44 GMT

I know you can't post pictures or files of your original model, but can you create a new model showing what you would like to accomplish and let's see if we can find a solution for you ?? Maybe a model with just the (4) legs / profiles ??

Sometimes it's difficult to understand what you want by text only. I am better explaining things with pictures than trying to explain it by talking.

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Re: Best way to model an adaptable frame?

JoshBretscher — Thu, 26 Apr 2018 17:50:28 GMT

Here is an example of one the legs. I'm looking to be able to have the initial extrusion length, Angle1, Angle2, Flat1, and Flat2, all automatically adjust themselves in an assembly according to constraints to other parts if I were to adjust the overall dimensions of the frame. Also, there would be many of this type of leg that would have different values for the extrusion, Angle1, Angle2, Flat1, and Flat2. I would like these to automatically adjust according to constraints within the assembly as well.

Re: Best way to model an adaptable frame?

torbjorn_heglum2 — Thu, 26 Apr 2018 18:31:23 GMT

If you use a master part to control size and shape of the individual parts and the assembly, member lengths and cut angles will be handled by the master part itself. The screencast below show how some dimensions are updated in the master part, and the assembly is updated accordingly. This model is fully controlled from the master part, the only added info in the assembly is machining.

Lengths and cut angles of the individual members is handled fully by the master part by standard part features, no parametric expressions or ilogic required. If another version is needed, the complete model including drawings is copied, the relevant dimensions is changed, and the new version is ready.

This model can be controlled by a higher level model (for instance a layout for the complete product or adaptive elements), but that will of course increase the complexity to a higher level.

Torbjørn

Inventor 2017.4

Re: Best way to model an adaptable frame?

JoshBretscher — Fri, 27 Apr 2018 13:50:14 GMT

Thank you for posting this video. Somehow when discussing the master part, the idea of actually building the frame in its actual form went over my head at first. I thought it was just a file that contained all possible parts that would then be used and constrained in assembly. I think this definitely the best solution.