Layers. Yes or no?

[lecra]

Hi all,

reading through the thread concerning 'Beginners Tips' I found this post of Edson:
click here

He said:

the three pillars of modelling well (IMHO, of course):

1. work ALWAYS on layer 0;
2. GROUP whatever geometry you are creating (in case there should be more than one copy of it, make it a COMPONENT);
3. place it on another LAYER whose name makes sense (essential for controlling the model's visualization).

I'm a little bit confused now! Should I just only draw on layer 0 and afterwards moving the objects on another layer? If yes, what is the advantage of this method? Why not build up the new object already on a new layer?

KR;Lecra

[mac1]

When you create a component the primitive geometry is still on layer 0. If you make a simple entity ,say a rectangle, make it a component, create a layer called rectangle, click on the component and use the entity info dialog you can assign it to the rectangle layer and turn the visibility on / off. If you now double click on that component , select a line and check its entity info it will report layer 0.
Hope that makes sense

[pbacot]

@alan fraser said:

Layers in SketchUp are not used the same way as in ACAD. They don't separate geometry; they are only useful for turning on and off to control visibility. If you attempt to do anything other than draw on the default layer, THEN move whatever you have drawn to another layer, you will very quickly find yourself in a sea of troubles.

You WILL forget to switch back to the default layer afterwards. You'll have groups and components on one layer, the contents of which are one one or more other layers; you'll have faces on different layers than the edges that define them.

Basically, you'll be screwed.

If I may, Alan means: " If you attempt to do anything other than draw on the default layer,GROUP OR MAKE A COMPONENT, AND THEN move whatever you have drawn to another layer..."

Also you don't HAVE TO make new layers and move your components (just leave on Layer0), but as soon as you get a bigger model it helps a lot.

It just works. Most of us learn the hard way with a confused model. There is a plugin that I still use regularly "Default Layer Geometry" to clean up mistakes and fix imported components.
("Geometry" here means bare lines, faces, arcs etc.)

Also use the context menu to move a group or compoenent to another layer.

[Gaieus]

Also, have a look at this video. It explains why grouping before putting those groups onto different layers is essential (and again, the geometry inside the groups will still b on Layer 0)

[Alan Fraser]

Layers in SketchUp are not used the same way as in ACAD. They don't separate geometry; they are only useful for turning on and off to control visibility. If you attempt to do anything other than draw on the default layer, THEN move whatever you have drawn to another layer, you will very quickly find yourself in a sea of troubles.

You WILL forget to switch back to the default layer afterwards. You'll have groups and components on one layer, the contents of which are one one or more other layers; you'll have faces on different layers than the edges that define them.

Basically, you'll be screwed.

Edit: Yes, by 'drawing' I did mean the entire drawing process, including making into a group or component...as Peter points out.
What this means from a practical point of view is that if, for instance, you have wrapped up geometry in a temporary group to avoid it sticking to adjoining geometry, then subsequently explode it; then that geometry will always revert to Layer 0...whatever layer the group was on...instead of spreading itself out over perhaps several layers.

[pilou]

Very cool video!

And some people don't never use Layers!
Just the Outliner! So they can say : Layers No
And sometimes layers at the end

[flash=420,315:7cxntj72]http://www.youtube.com/v/o9cNdODWm-c[/flash:7cxntj72]

[lecra]

Hi guy's,

Thank you very much for your professional explanation as well as for the video tutorial links. To summarize your answers and to check if I understood your suggestions this is the workflow for using layers:

1. Draw everything on Layer 0 and be sure that this is the active layer
2. After that convert the object you have just drawn in a group or component
3. You can then put the converted object on different layer
4. With components/groups on different layers you can ensure a better visibility in a more complex model due to the fact that you can hide/unhide objects

Is that the added value of working with layers in a few words?

KR; Lecra

[Dave R]

That's pretty good. Whether or not you are using layers, you should make components or groups because that's the only way to keep things from sticking together. When you are making layer associations make sure it is only the component/group that gets the assignment. The geometry inside still remains on Layer 0. When you turn off the layer's visibility, it is sort of like when the Klingons activated their cloaking device in Star Trek. The group or component is still there. You just can't see it.

[Gaieus]

Well, that's the sole reason for working with layers. The "rules" are correct.

If you change the active layer, whatever you draw (add now geometry) will be drawn on that layer. This is why you should not do that.

In addition, Layer 0 is a special layer. With all loose (or primitive) geometry on layer 0 you can turn that layer off (if you change the active layer) but that geometry won't disappear.

There is one (IMO buggy) behaviour in SU that you need to take care of: when there is a group/component on a certain layer (other than layer 0) and you explode this group/component, all the geometry will default to that layer (not to layer 0 where it was). This can mess up your model. There is a solution though. When you explode a group, all its content is still selected. With that selection active, quickly change the layer back to layer 0 in the Entity info box.

Finally for hopelessly screwed up models, use this plugin:
http://forums.sketchucation.com/viewtopic.php?t=7638

[pilou]

@unknownuser said:

1 - Draw everything on Layer 0 and be sure that this is the active layer
2 - After that convert the object you have just drawn in a group or component
3 - You can then put the converted object on different layer
4 - With components/groups on different layers you can ensure a better visibility in a more complex model due to the fact that you can hide/unhide objects

and for be complet
5 - Enable / Disable layers wanted visible or not

and this plug also by Chris Fullmer
loose Geometry to groups

[lecra]

Again guy's: many, many thanks for your tremendous and fast support! It's really appreciated.

You all, have a nice weekend. Stay away from your computers once and dedicate your time to your families and friends!

With my best regards. Lecra

[Wo3Dan]

@alan fraser said:

...What this means from a practical point of view is that if, for instance, you have wrapped up geometry in a temporary group to avoid it sticking to adjoining geometry, then subsequently explode it; then that geometry will always revert to Layer 0...whatever layer the group was on...instead of spreading itself out over perhaps several layers.

No Alan, when exploding a group or component, all that is inside and still default (as for layers0 and default texture) will inherit the groups layer and its texture.
I'm sure you know and it's just a little mistake.

@gaieus said:

...There is one (IMO buggy) behaviour in SU that you need to take care of: when there is a group/component on a certain layer (other than layer 0) and you explode this group/component, all the geometry will default to that layer (not to layer 0 where it was). This can mess up your model. There is a solution though. When you explode a group, all its content is still selected. With that selection active, quickly change the layer back to layer 0 in the Entity info box.

Like Gaieus says. And the same behaviour applies to textures. Default entities inside the exploded environment inherit the groups layer and its texture.