Learning how to effectively use groups is one of the most important things you should know about Sketchup. The Outliner provides a way for you to keep track of all the groups you have made in the model by assigning a name to them, and viewing the hierarchy of how they are organized.
Groups provide organization
Components are very similar to groups, except that each instance of a component is an exact replica of one another. If any changes are made to one component, all copies of that component reflect those changes as well. Groups are independent from one another, meaning that once you’ve created a copy, you can edit one of them and the changes do not affect the other instances of that similar group. Each one is independent from the next.
For the sake of this article, we will be talking mostly about groups, but you should understand the differences between the two. However, the bounding box system acts the same whether it is a component or a group, so I don’t need to differentiate between the two in this context.
A collection of faces and edges within a model that are isolated from other parts of the model.
- Anything protected in a group cannot by affected by any geometry outside of that group.
- To manipulate faces or edges within a group, or to add geometry to a group, that group must first be “activated” by double clicking on it.
- If you draw a shape on something that is in a group, it won’t “stick” to the object unless you open the group first.
- Groups can contain “loose geometry”, guides, section planes, dimensions, text, or other groups.
- Groups can be manipulated as an assembly. (Move, rotate, scale, paint, copy, etc)
- Groups have their own independent 3-axis from the rest of the model, and it can be reoriented
- Copies of groups are independent from one another. Once a copy is made, any changes made to one instance of that group do NOT affect the other copies of that group.
Similar to groups, except that each copy of a component remains identical to its original. Any changes made to an instance of a component are automatically reflected to each instance of that component.
- Using Components for multiple copies of the same object within a model increases the performance of Sketchup when compared to using groups to do the same thing. That’s because Sketchup only has to define a component one time, whereas with groups, Sketchup has to define each and every group even if each group is technically identical.
- Components can be saved independently from the current model and imported into other models. If you make any changes to the component, you can update the reference in any models you’ve imported it into.
- You can assign a “gluing plane” to components. A gluing plane allows the component to automatically orient itself onto the face of the object you are moving it to. For example, if you had a component of a picture frame, you would want it to be placed flat on a wall. Depending upon which wall you place the component on, you would have to rotate the picture 90° and reposition it onto the wall. By defining a gluing plane, the component will automatically rotate as you move it so that it is oriented properly to whichever wall you are moving it to.
- Components can be configured to “always face the camera”. When you first open Sketchup, you’ll notice how the person inside every default model always faces you, even as you orbit around the model. You can assign this property to components too.
- If you want to make an instance of a component unique from its counterparts, you can right click it, and select “Make Unique”.
Groups, and the Outliner
In this simple sketchup model, I have 3 boxes. Two of the boxes are in group A, and one box is in group B. Creating a group is easy. Just select all of the entities you want to group, then right click, select make group. If you look at the outliner, you will see each group you have in the model.
If you don’t see the Outliner window, go to Window -> Outliner
In this example, I have a total of 4 groups; Group A, Group B, Subgroup 1, and Subgroup 2. Later on, you’ll notice the components named “box”, nestled in various groups. (Notice how each of the 3 boxes are identical in size? That’s because they are each an instance of the same component.) A look at the outliner quickly reveals the hierarchy.
- GROUP A
- SUBGROUP 1
- SUBGROUP 2
- SUBGROUP 1
- GROUP B
A group usually contains one of two things; “loose” entities, or other groups. That’s right, you can have a group within a group. You can also have a group, within a group, within a group… There’s really no end to the amount of grouping you can do within a model. It’s up to you to decide the organizational structure of your model.
Manipulating the “stuff” inside a group
What’s nice about having a bunch of parts inside of a group is that it allows you to manipulate those things as a whole, instead of each individual part. For example, you could rotate the entire group as a unit. You can move it, scale it, paint it, and more, as a group. I try to make “assemblies” of things and and group them together to make it easier to position things.
For example, if I were building a wall with 2×4’s in Sketchup, I would select each 2×4 individually, and create a group out of them. That way if I need to move the wall a few inches, I can just select the entire group and move it without having to select each board individually.
I also group things in ways that allow me to hide major parts of my model so I can work on a different part without having too much stuff in my way. The outliner is great for unhiding those items because you can easily select the text of the hidden item, right click, and select unhide.
But you’ll also need to know how to manipulate the parts inside of a group.
In this example, you can see “Group A” contains two “Subgroups”, named “SUBGROUP 1″ and “SUBGROUP 2″. The lines and faces that make up the 3D text and the two arrows are “loose” entities within GROUP A. Once Group A is activated, you would be able to select and manipulate the individual faces and edges that make up those arrows and text.
When you select a group, all of the entities within the group are highlighted blue, and an imaginary blue box is formed around them. This blue box represents the boundaries of what is contained within it.
When you activate it by double clicking, a few things happen. First, you’ll notice the solid blue bounding box has turned into a black dotted line bounding box. This lets you know what group is currently “active”. The entities within that group are not highlighted anymore, but the outliner window will show all active groups with blue text. Also, you’ll notice any entity that is not part of the group will be “greyed” out.
In the image above, we’ve activated GROUP A. You’ll notice GROUP B is “greyed out”, indicating that it is not part of the active group.
Now that GROUP A is activated, let’s see what is in this group. We already know that there are two subgroups in GROUP A by looking at the Outliner. If you click on the subgroup name in the outliner, it will select the corresponding subgroup in the model and highlight it blue.
You can activate subgroups the same way you activated the group you’re currently in.
When editing anything in a group, you need to make sure your selections are made within the dotted line bounding box. If you click outside the area of this bounding box, you will activate the “parent group” of the one you are currently working in.
Keep this in mind when you are working on models with groups that have overlapping bounding boxes. You have to click outside of the bounding box area to go up one level in the group hierarchy. So if you have 4 levels of subgroups, you would have to click outside of the bounding boxes 4 times to return to having no groups activated.
The next time you create a model, really think about how you want to organize your model. What different parts should you separate from each other? What parts should be moved together as an assembly? Is this something I’m going to make an exact copy of, over and over? Should I use a component instead of a group? Making these decisions early on will help you stay organized.
PS – Notice I didn’t say a word about Layers…Ha ha! Have fun and stay organized!