Assemblies, subassemblies, parts in the objects tree after inport
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Dmitriy Dyakov
Complex models have a structure of Parts and Subassemblies in hierarchical dependence, in some cases in one is enclosed in another, etc.
Sometimes it is necessary to work with a complex model, for example, a robot with engines, arms, legs, etc.
There is a need to work with a model tree that allows us to show a hierarchy of components (nested parts and assemblies) select and move the components with all in the nodes, also turn on/disable visibility with hierachical sets.
It is also important that the part of the same name in the assembly or subassembly is an instance, and when editing its geometry changes every instance where it is used.
BunnyViking
However it's done, we desperately need some sort of organisational system / hierarchy. Even things as simple as moving 2 objects that aren't connected at the same time can be a problem, let alone moving, duplicating, trying to accurately array a group of objects that you can't bool together because they aren't coincident (let alone that you just dont want to bool together)
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Dmitriy Dyakov
BunnyViking Right! Imagine creating a robot arm with a hand and fingers. How to manage this?
Here we need subassemblies with parts inside, so that by moving/rotating one subassembly, all parts belonging to the subassembly move/rotate.
Mark Landsaat
I think this can be achieved quite easily with layers and sublayers. I use this method in Rhino to create something that is quite similar to a parametric feature tree
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Dmitriy Dyakov
Mark Landsaat: How will you export/import a design to exchange with an engineer who works in SolidWorks, NX, Creo?
You will constantly have the model tree disappearing at the next iteration of the collaborative exchange betwen CAD and Plasticity. Either you or the engineer will have to recreate the model (scene) tree many times after the exchange in STEP/IGES.
Mark Landsaat
Dmitriy Dyakov: I'm not sure what you mean by that. Anytime you exchange a model between two different CAD programs the native feature tree is lost. I'm not aware of any software that maintains the feature tree. I work with customers that use all kinds of different software, and the only way to maintain the native tree is if both people are not only on the same software, but on the same version.
In SolidWorks if two people are on different versions you can only exchange designs in a neutral format losing all of the parametric history in the process.
Grouping things in the outliner kind of works like creating assemblies and sub-assemblies, but layers would add additional functionality.
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Dmitriy Dyakov
Mark Landsaat: I have no problem when I export a model from Fuion 360 to STEP and then import it into CATIA and Solidworks. The model tree (product hierarchy) is always transferred correctly. I get assemblies, subassemblies and parts in the tree with any STEP, IGES import.
I agree that it would be better to work in one CAD system, but it doesn't always work that way, especially with customers/partners/contractors.
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Dmitriy Dyakov
Mark Landsaat:
I wasn't talking about a parametric or history tree for creating model geometry, I was talking about a object tree in model.
I also agree that layers are handy, but not instead of the object tree in the model.
For example 3D MAX combines layers with object groups in outliner, and the user can choose between object groups/subgroups and layers/sublayers. The user can also use both methods at once.
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Dmitriy Dyakov
Mark Landsaat: Here I have imported in Plastisity an assembly in STEP with parts and subassemblies, but I get bodies, not even parts - bodies! 🤦♂️
What should I do with it, should I group and rename each body again? 🤯 I'm sure that's not the best approach. What do you think?
Now imagine that this is only a small PCB model, and there are more parts...
Mark Landsaat
Dmitriy Dyakov: Yes I see what you are saying now, keeping the grouping would be very useful
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Dmitriy Dyakov
Mark Landsaat: Also, in CAD each same part of assemble can be instances (not just a body or copy) it's convenient. And layer cannot be an instance, but a part or assembly may well be.
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Dmitriy Dyakov
Also, it is much easier to select groups/subassemblies for group movement of objects than to select parts separately and move each one.
