Level of detail

[drawingsCHR7R]

Good morning to everyone!

Could someone please give me a simple explanation as to what a level of detail is and why is it used? 

I am a bit confused on this and just want a better understanding of it.

Thanks

[Anonymous · Accepted solution]

The 99% correct answer is "don't use it", regarding the 'use'.

Level of detail is a way of restricting the number of files that have to be read, and the number of objects that are in memory and have to be processed for each command. If you were to design a train then it would make sense to have the entire bodywork fully detailed, including each rivet and screw. If you then would start a higher level assembly, where you combine the structure and the body in order to create an assembly of the seats, then this could seriously slow down your work. It would then make sense to create a 'level of detail' in the bodywork-assembly, where you suppress all the small stuff and keep the large panels only. This 'level of detail' would be sufficient to get a descent seat layout.

The practical restriction of 'level of detail' is that when parts are suppressed in assembly, the same is true for the relations they hold. If not thoroughly prepared, you're bound to meet "situations".

With the present state of hardware and memory the effective way to walk is working with views. Visually a view will also avoid clutter and make things easier to work with. But it doesn't impact the functioning of the assembly.

[johnsonshiue]

Hi! Instead of learning what LOD is, I think it is better to understand what you really want to do. Please share your thoughts on what you want to do with LOD. Forum experts can guide you through the best workflows.

Many thanks!

[drawingsCHR7R]

Hi @johnsonshiue It is not a matter of what I want to do it is just that I have come across it on more than a few occasions and I have not really been able to understand what the purpose of it is and what role it plays in Inventor. So that is why I asked what it is used for and why one would save a level of detail. The answer I received allowed me to have a much better understanding of it but if you would like to elaborate more I would be more than open to see what you have to say/teach.

[jtylerbc · Accepted solution]

It's intended purpose is to reduce the memory load on your computer while working in very large assemblies, as @Anonymous described. Unfortunately, its most common actual use is probably by mistake by users that should have been using View Representations instead.

For whatever reason, when trying to hide a part, it seems like newer users very often find the "Suppress" option before they discover "Visibility".  Both will remove the part from view.  But Suppression is really a tool for memory management, and the invisibility should be thought of almost as a side effect, rather than the purpose of the setting.  I suspect the reason is that new users carry the term "Suppress" over from other software, where it may have meant something a little different.  Level of Detail (LOD) is simply a way of saving combinations of Suppressed components.

If you use LOD's where you don't need them, you will be opening yourself up to all sorts of annoying little problems.  These problems are tolerable consequences if you actually needed the performance-boosting effects that the LOD is designed for.  But if you're not hurting for computer performance, you're causing yourself trouble without gaining anything from it.

If all you are doing is hiding objects, Visibility and View Representations are the way to do it.  Like LOD's are for Suppression, View Representations are a way of saving combinations of Visibility settings (and also color overrides).  

LOD's are in some ways a relic of the past.  In older operating systems (32 bit), they were often necessary to keep large or highly detailed assemblies practical to work in.  With 64 bit operating systems, a model has to be huge to actually need them.  Although I occasionally have to clean up some that were created mistakenly by newer users, we have not used LOD's intentionally at my company since about 2011.  The largest assemblies that the company has ever created are still not large enough to need any LOD's on a modern computer.

There are also some applications for them in iLogic automation, where they are used as part of a technique for creating configurable assemblies.  This has been an occasional exception to my rule of not using LOD's, though it hasn't come up often.  LOD''s on their own (without programming code backing them up) are not useful as a configuration tool, and shouldn't be used that way if you value your mental health.

Bottom line, there is very little reason for you to use LOD's today.  The exceptions would be if you are working on a model that is absolutely enormous, or if you are building some sort of iLogic smart model.  But you do need to be aware of the possibility that users may have used them in the past for situations where View Representations would have been a better choice.  Learning the basics of how to use them wouldn't be a terrible idea, in case you're ever faced with the prospect of needing to continue a previously-established convention of using LOD's in a particular assembly.  But in general, you should avoid using them because they typically aren't needed anymore.

[drawingsCHR7R]

Thank you for the awesome explanation!

So when I am working with an assembly and save the file it will ask me to save as a LOD, how do I avoid this? or how do I set inventor to not ask me to save a file as a LOD again?

[Anonymous]

As I understand it, most of the LOD's in assemblies are coming from people that are working in a large assembly that is getting cluttered. In analogy with Part-environment they start suppressing elements in the assembly. The next thing happening on 'save' is that IV asks to save that situation in a level-of-detail. Lots of people have no clue (probably the same for others warnings... 😁 ...) and they say 'yes'. Et voila, your assembly is left in a - practically invisible - state of LOD, that you're not aware of, and you continue working.

My 0,02€ of advice is another KISS-rule (*) : if there are 30 or more single objects in your assembly you need a  sub-assembly. Or at least an internal folder to group the similar stuff. And next : use view-reps. Combination of both allows you to restrict your environment to what you need to see to do your job.

To the side of this, few people know the existence of 'edit include components'. It works when you are in a view (unlocked) and you're not seeing what you expect and/or need. The 'edit include components' takes the Sherlock Holmes practice out of your hands, as you can ask the command to show the elements that are NOT in view. A simple click and you return to your view with the one missing element in display.

[drawingsCHR7R]

Hi, thanks for your inupt here, I love the idea of using 'edit including components' I think that I will definiteyl be using it in the future!

Do you by any chance know how to tell Inventor to stop asking me to save my file as a LOD?

[jtylerbc]

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@drawingsCHR7R wrote:

So when I am working with an assembly and save the file it will ask me to save as a LOD, how do I avoid this? or how do I set inventor to not ask me to save a file as a LOD again?

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The instant you Suppress a component, you have told Inventor to create a LOD.  Suppression states can not be saved unless you are in an unlocked LOD.  If you are currently in a locked LOD (such as "Master"), an editable LOD will be created.

Stop Suppressing components, and it will stop asking to save an LOD.  There is no need for a setting to make it stop asking, because it only does so in direct response to what you have told it to do.

[Anonymous]

It will ask you to save a level-of-detail because you have suppressed a component. If all components are 'live' you won't be asked.

[drawingsCHR7R]

Ahhh, I see. Alright thanks I will definitely keep that in mind going forward.

Appreciate the assistance here!

[AstratecLichtervelde]

Good suggestion!

I have an small assembly with a custom level of detail (name: LOD2) in order to hide some of the created workplanes and axes.

When I import this small assembly in a big assembly and I choose LOD2 as my level of detail in the big assembly, all the workplanes and axes are still visible in the big assembly.

The whole point of this created level of detail was to hide them, but they are visible.

Please explain and provide solution for Inventor 2021, thank you very much!

[jtylerbc]

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@AstratecLichtervelde wrote:
Good suggestion!

When I import this small assembly in a big assembly and I choose LOD2 as my level of detail in the big assembly, all the workplanes and axes are still visible in the big assembly.

The whole point of this created level of detail was to hide them, but they are visible.

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If the whole point of creating an LOD was to hide planes, there was no reason to create the LOD at all. Why are you trying to use a memory management tool to control plane visibility?

You should be using a View Representation instead of LOD.  Once you set that up in the subassembly, go to your main assembly.  Right click on the subassembly, and pick "Representations" in the menu.  In the dialog box that pops up, choose the desired View Representation, then make sure to check the "Associative" box.

If you don't check the "Associative" box, the subassembly shown in the main assembly will look correct initially, but will not update to changes to the View Representation later.

[AstratecLichtervelde]

Thank you for your response and explanation.

I can't speak for other designers, but I'm not having memory issues like I'd need a memory management tool directly available from the assembly tree, as there is some other nice tool which manages memory if needed and it's called express mode.

I feel like designers mostly want a good workflow by turning things on and off, and be able to see that across all project models.

That's why I used the level of detail because it's directly available in the assembly tree.

It's a little bit obnoxious that LOD reps are directly shown in the assembly tree, but selecting view reps require a workaround and extra options in the RMB menu.

I just think it's a good UI practice to put things that are used more frequently on the foreground.

[johnsonshiue]

Hi Astratec,

As John mentioned earlier, LOD was not designed to hide origin planes, though it does unload the document and the origin planes will not be visible.

To hide origin planes or workplanes, you could use View -> Object Visibility or Design View.

Many thanks!

[pgebbia]

How do I delete the Level of detail representation if I accidentally used Suppress? 

[johnsonshiue]

Hi! Activate LOD:Master and delete the newly created one.

Many thanks!

[r0938644]

Hi, 

I tried that but there's still a tab 'Level of Detail : Master' which has 4 standard LOD's (All components supressed, all parts supressed, all content center supressed and master). Is this something that's standard in an assembly or can i delete this to? 
If i right click on it, there's no option to delete it so if i should get rid of it, how do i do so?

[johnsonshiue]

Hi! What release of Inventor are you using? Please share the files that exhibit the behavior. I would like to understand the issue better.

Many thanks!

[r0938644]

I'm working with the 2020 version for my company. I accidentally created an LOD and then deleted it, but i still have the tab with "standard" (?) Lod's. 

Is this normal? Would this impact my assembly in any way or can i just leave it like that? 

Thanks for your help!