Hi Danny, yeah I could definitely use some more information, that whole system is not at all clear to me currently.

> The category becomes the parent to the layers, where you
> can control on/off of individual layers or turn on/off the
> category which contains those layers.

I'm not really following... Like for example what if you have "Category A" which is a parent of "Layer 1" and "Layer 2". Then you have "Category B" which is a parent of "Layer 1" and "Layer 5".

Now you set Category A to be turned off, and Category B to be turned on.

What happens to things on "Layer 1" - should things on layer 1 be turned off like Category A says, or should they be turned on like Category B says?

Or do objects not belong to a layer and instead belong to a category, or something like that?

I think your layer system there is kind of different than what I am used to thinking of as "traditional" layers - to me traditional layers means a system like AutoCAD where you have a list of layers, each of which has a name, a color, and an on/off state (and other properties like line type, etc...). Objects reside on one layer and they take on the appearance and properties of the layer that they are on.

If what you refer to as "layers" do not have properties like colors associated with them, I guess they may be a kind of different concept or something... ?

- Michael

>What happens to things on "Layer 1"
> - should things on layer 1 be turned off
> like Category A says, or should they be
> turned on like Category B says?

Layer 1 actually turns off with that category, but you can switch that individual layer back on, then you'll have a mixed state of Category A.
We don't really use categories in this way, we control that sort of grouping stuff with the component assembly tree where you have sub assemblies under a parent assembly.
I know it sounds complicated but it isn't really once you understand the logic of it all, and no, it's not like Autocad or Rhino layer system, I think it's more for a Mech eng cad system.

> I could definitely use some more information.
No Problem, I'll have something up tomorrow for you.

Cheers
~Danny~

Hi Michael,

It seems we've got different interpretations and experiences in what we think a traditional layer system is.
Unigraphics (NX) was first developed in the '70's so there was no influence from Autocad which came out in the '80's.
Mechanical cad systems that I've worked with have always been 256 layers, some called them levels. I'll explain how NX handles object organisation, in a single 3d space and history free, parametric modelling and using sub assemblies within assemblies is also used for object organisation but that's a different story.

Layers in NX is just a container for an object or objects, it does not control the object attributes, like colour, line thickness, etc. all you can do with a layer is control the object interactive/visual state on the screen, like; Work(active), Selectable, Visible Only, Invisible.
Colours and the other object attributes are per object and controlled separately with the object preferences window, so you can have as many objects with different attributes for each, under one layer.

The basic layer window, layers on the right and what categories those layers are in on the left, note layer 62 is in 2 different categories.
when you right click on a layer you get the visual options.



Then when you tick the box that says 'Category Display' you get the categories in a hierarchy tree showing layers are under each category.



To change the object attributes for the work (active) layer you bring up the 'Object Preferences' window (left picture), to edit object attributes you right click on the object and pick 'edit object display' and that will bring up the 'edit object' window (right picture).




Once you've assigned layers and attributes to an object, it's a matter of using the layers, the filter system and hide/show to manage you work.

This is the filter system, which you can filter objects by types, colours, layers, etc.



'Type' selection filter.



'Colour' selection filter.


That's it in a nutshell. It would be easier and clearer if I actually showed the system on screen in action.

Any questions, feel free.

Cheers

Hi Danny,

> It seems we've got different interpretations and experiences
> in what we think a traditional layer system is.
> Unigraphics (NX) was first developed in the '70's so there was
> no influence from Autocad which came out in the '80's.

The AutoCAD layer system tends to be the one that is much more commonly used by quite a range of PC CAD software...

Certainly a system that originated off of a PC will tend to have a different history, and although there is nothing necessarily wrong with that system that you are showing there, I think it would be hard to incorporate that exactly since it is just not what the much wider majority of people would expect when you use the term "layers".

Here are some examples of layer systems from other CAD-ish programs currently on my machine:

Rhino:



SketchUp:



DoubleCAD XT:



ViaCAD:



Alibre 2D drawing module:




Notice how they all general fit the same pattern where a "layer" is an entity that has a name, and certain properties such as color and linetype.


It's just by far the most common thing that is done...


One big problem that would prevent me from adopting the system that you are showing there would be having colors assigned as an individual object property, rather than the color coming as a kind of named entity.

That's because one big purpose of setting this up in MoI is to translate that into material assignments. It is easier to control materials when there is a list of available named materials, and you can assign an object to belong to one of those rather than just a color value directly, because you may want to do things like set up materials like "Spaceship hull damaged", "Spaceship hull 1", "Spaceship hull 2", to have things arranged into different categories but not necessarily mess with having different actual colors set to them quite yet, until later when you are altering the materials in your rendering program.

So for instance it would not be unusual for someone to have set up 3 "styles" in MoI all of which are black currently but still have a separate identity. If all things that were Black had the same "material identity", it would prevent that kind of workflow...


At any rate, the Groups mechanism is meant to be a kind of container system, it may more closely align to the layers that you are accustomed to.

- Michael

Hi Michael,

I understand what you are trying to do with MoI and I agree that the layer systems you're showing there are restrictive, the reason why I couldn't understand where you were coming from, is because I was used to a whole different system.
The layer system that most other cad vendors have followed is from Autocad, which I don't think has ever evolved from the 2d world of past. I wonder how Autodesk handled Mechanical Desktop's layer system.

> At any rate, the Groups mechanism is meant to be
> a kind of container system, it may more closely align
> to the layers that you are accustomed to.

No doubt when Groups are implemented, MoI will be flexible enough to accommodate different ways of object organization, keep up the good work.

Cheers

Hi Danny, yeah they are kind of restrictive which is why I didn't want to jump right into having only that system for organizing objects and nothing else...

However on the other hand, those kinds of layers are pretty simple and easy to understand, and also are very widely used to control color.

It's that common connection with color that I was trying to demonstrate with those screen shots from various other programs.


So anyway, that's why mapping styles in MoI to layers in certain CAD-type export formats seems to be a good matchup.

- Michael